Lesson 1: Main Content for Module 2

Fermentation is the production of ATP in the absence of oxygen by the process of Glycolysis. A byproduct of this process is lactic acid which is what brings Ph of substrate down and brings sour taste. Glucose – Pyruvate (Nadh) – Atp – Lactic acid. Fermentation can also occur with oxygen and some bacteria can ferment via anaerobic and aerobic environments which are called Facultative bacteria.

( Aerobic / Anaerobic & Facultative) Fermentation:

Destroys most of anti-nutrients
Increases phenolic content due to microbial hydrolysis reaction
Produces beneficial enzymes
Produces beneficial bacteria
Breaks down cell wall to liberate nutrients and makes them bioavailable

Introduction

After the photosynthetic “oxygen catastrophe” challenged life between 2.5 and 3 billion years ago, evolution rebounded with biochemical pathways to harness and protect against oxygen’s power. Today, most organisms use O2 in aerobic respiration to produce ATP. Almost all animals, most fungi, and some bacteria are obligate aerobes, which require oxygen. Some plants and fungi and many bacteria retain the ability to make ATP without oxygen. These facultative anaerobes use ancient anaerobic pathways when oxygen is limited. A few bacteria remain as obligate anaerobes, which die in the presence of oxygen and depend on only the first (anaerobic) stage of cellular respiration.

Aerobic and anaerobic pathways diverge after glycolysis splits glucose into two molecules of pyruvate: Anaerobic and aerobic respiration share the glycolysis pathway. If oxygen is not present, fermentation may take place, producing lactic acid or ethyl alcohol and carbon dioxide. Products of fermentation still contain chemical energy, and are used widely to make foods and fuels. Pyruvate still contains a great deal of chemical energy. If oxygen is present, pyruvate enters the mitochondria for complete breakdown by the Krebs Cycle and electron transport chain. If oxygen is not present, cells must transform pyruvate to regenerate NAD+ in order to continue making ATP. Two different pathways accomplish this with rather famous products: lactic acid and ethyl alcohol . Making ATP in the absence of oxygen by glycolysis alone is known as fermentation. Therefore, these two pathways are called lactic acid fermentation and alcoholic fermentation. If you lack interest in organisms, such as yeast and bacteria, which have “stuck with” the anaerobic tradition, the products of these chemical reactions may still intrigue you. Fermentation makes bread, yogurt, beer, wine, and some new biofuels. In addition, some of your body’s cells are facultative anaerobes, retaining one of these ancient pathways for short-term, emergency use.

Lactic Acid Fermentation: Muscle Cells and Yogurt

Yes! Muscle color reflects its specialization for aerobic or anaerobic metabolism. Although humans are obligate aerobes, our muscle cells have not given up on ancient pathways which allow them to keep producing ATP quickly when oxygen runs low. The difference is more pronounced in chickens and grouse (Figure below), which stand around all day on their legs. For long periods of time, they carry out aerobic respiration in their “specialized-for-endurance” red muscles. If you have ever hunted grouse, you know that these birds “flush” with great speed over short distances. Such “sprinting” flight depends on anaerobic respiration in the white cells of breast and wing muscle. No human muscle is all red or all white, but chances are, if you excel at running short distances or at weight lifting, you have more white glycolytic fibers in your leg muscles. If you run marathons, you probably have more red oxidative fibers. Ruffed grouse use anaerobic respiration (lactic acid fermentation) in wing and breast muscles for quick bursts of speed to escape from predators (and hunters!). You probably were not aware that muscle cells “ferment.” Lactic acid fermentation is the type of anaerobic respiration carried out by yogurt bacteria (Lactobacillus and others) and by your own muscle cells when you work them hard and fast. Converting pyruvate to 3-carbon lactic acid (see Figure below) regenerates NAD+ so that glycolysis can continue to make ATP in low-oxygen conditions.

For Lactobacillusbacteria, the acid resulting from fermentation kills bacterial competitors in buttermilk, yogurt, and some cottage cheese. The benefits extend to humans who enjoy these foods, as well. Lactobacillus bacteria use the same type of anaerobic respiration as our muscle cells. Lactic acid reduces competition from other bacteria, and flavors yogurt, as well! You may have noticed this type of fermentation in your own muscles, because muscle fatigue and pain are associated with lactic acid. Keep this in mind, however, as we discuss a second type of fermentation, which produces alcohol. Imagine what would happen as you ran a race if muscle cells conducted alcoholic rather than lactic acid fermentation!

Alcoholic Fermentation: A “New” Source of Energy?

Have you fueled your car with corn? You have, if you bought gas within the city of Portland, Oregon. Portland was the first city to require that all gasoline sold within the city limits contain at least 10% ethanol. By mid-2006, nearly 6 million “flex-fuel” vehicles – which can use gasoline blends up to 85% ethanol were traveling US roads. This “new” industry employs an “old” crew of yeast and bacteria to make ethanol by an even older biochemical pathway – alcoholic fermentation. Many people consider “renewable” biofuels such as ethanol a partial solution to the declining availability of “nonrenewable” fossil fuels. Although controversy still surrounds the true efficiency of producing fuel from corn, ethanol is creeping into the world fuel resource picture

Aerobic vs. Anaerobic Respiration: A Comparison

As aerobes in a world of aerobic organisms, we tend to consider aerobic respiration “better” than fermentation. In some ways, it is. However, anaerobic respiration has persisted far longer on this planet, through major changes in atmosphere and life. There must be value in this alternative way of making ATP. In this last section, we will compare the advantages and disadvantages of these two types of respiration. A major argument in favor of aerobic over anaerobic respiration is overall energy production. Without oxygen, organisms can only break 6-carbon glucose into two 3-carbon molecules. As we saw earlier, glycolysis releases only enough energy to produce two (net) ATP per molecule of glucose. In contrast, aerobic respiration breaks glucose all the way down to CO2, producing up to 38 ATP. Membrane transport costs can reduce this theoretical yield, but aerobic respiration consistently produces at least 15 times as much ATP as anaerobic respiration. This vast increase in energy production probably explains why aerobic organisms have come to dominate life on earth. It may also explain how organisms were able to increase in size, adding multicellularity and great diversity. However, anaerobic pathways persist, and a few obligate anaerobes have survived over 2 billion years beyond the evolution of aerobic respiration. What are the advantages of fermentation? One advantage is available to organisms occupying the few anoxic (lacking oxygen) niches remaining on earth. Oxygen remains the highly reactive, toxic gas which caused the “Oxygen Catastrophe.” Aerobic organisms have merely learned a few tricks – enzymes and antioxidants – to protect themselves. Organisms living in anoxic niches do not run the risk of oxygen exposure, so they do not need to spend energy to build these elaborate chemicals. Individual cells which experience anoxic conditions face greater challenges. We mentioned earlier that muscle cells “still remember” anaerobic respiration, using lactic acid fermentation to make ATP in low-oxygen conditions. Brain cells do not “remember”, and consequently cannot make any ATP without oxygen. This explains why death follows for most humans who endure more than four minutes without oxygen. Variation in muscle cells gives further insight into some benefits of anaerobic respiration. In vertebrate muscles, lactic acid fermentation allows muscles to produce ATP quickly during short bursts of strenuous activity. Muscle cells specialized for this type of activity show differences in structure as well as chemistry. Red muscle fibers are “dark” because they have a rich blood supply for a steady supply of oxygen, and a protein, myoglobin, which holds extra oxygen. They also contain more mitochondria, the organelle in which the Krebs cycle and electron transport chain conclude aerobic respiration. White muscle cells are “light” because they lack the rich blood supply, have fewer mitochondria, and store glycogen rather than oxygen. When you eat dark meat, you are eating endurance muscle. When you eat white meat, you are eating muscle built for sprinting. Each type of muscle fiber has advantages and disadvantages, which reflect their differing biochemical pathways. Aerobic respiration in red muscles produces a great deal of ATP from far less glucose – but slowly, over a long time. Anaerobic respiration in white muscles produces ATP rapidly for quick bursts of speed, but a predator who continues pursuit may eventually catch a white-muscled prey.

In summary, aerobic and anaerobic respiration each have advantages under specific conditions. Aerobic respiration produces far more ATP, but risks exposure to oxygen toxicity. Anaerobic respiration is less energy-efficient, but allows survival in habitats which lack oxygen. Within the human body, both are important to muscle function. Muscle cells specialized for aerobic respiration provide endurance, and those specialized for lactic acid fermentation support short but intense energy expenditures. Both ways of making ATP play critical roles in life on earth.

Lesson Summary

In the two to three billion years since photosynthesis added oxygen to earth’s atmosphere, life has become mostly aerobic. Some organisms and types of cells retain the older, anaerobic pathways for making ATP; these pathways comprise anaerobic respiration or fermentation.
Obligate aerobes require oxygen to make ATP. Obligate anaerobes cannot survive in the presence of oxygen, so they occupy only anoxic habitats. Facultative anaerobes make ATP with oxygen, but if oxygen levels become low, they can use fermentation.
Some bacteria, including those we employ to make yogurt, make ATP using lactic acid fermentation; the acid may help reduce competition from other bacteria. Muscle cells can continue to produce ATP when O2 runs low using lactic acid fermentation, but muscle fatigue and pain may result.
Red muscle fibers use mostly aerobic respiration to make ATP for endurance tasks; white muscle fibers use mostly lactic acid fermentation to make ATP quickly for short, intense activities. Human muscles contain a mixture of red and white fibers, but genetics may give sprinters more white fibers, and marathoners more red.
Both alcoholic and lactic acid fermentation pathways change pyruvate in order to continue producing ATP by glycolysis.
Ethanol produced by bacteria through alcoholic fermentation of corn (and perhaps other fuels in the near future) may provide a more renewable fuel for vehicles than the fossil fuels upon which we currently depend. We employ yeasts to help make bread through alcoholic fermentation; as they produce carbon dioxide, the bread dough rises. We employ anaerobic organisms to make beer and wine through alcoholic fermentation; the alcohol content is limited to 18% by volume because levels above that are toxic to these organisms.
Aerobic respiration is far more energy-efficient than anaerobic respiration. Aerobic processes produce up to 38 ATP per glucose. Anaerobic processes yield only 2 ATP per glucose.

Review Questions

Classify your own cells as obligate aerobes, obligate anaerobes, or facultative anaerobes, and explain your reasoning. (Although these terms usually apply to whole organisms, assume they can also apply to individual cells within your body).
Identify yourself as a “sprinter” or an “endurance runner” and predict the type of muscle fiber (red or white) which predominates in your body. Explain your reasoning.
Construct a chart which compares alcoholic to lactic acid fermentation, considering at least three different features.
Outline the process used to produce fuel from corn and explain why some consider this fuel “renewable” and preferable to fossil fuels. Research the pros and cons of this fuel.
Explain how fermentation is used to make Yogurt.
If two species of bacteria – one using aerobic respiration and the other using anaerobic respiration – were competing for the same source of glucose in the same environment, which one would out-compete the other? Explain why.
Human cells cannot carry out alcoholic fermentation, yet we use it for many purposes. Analyze its importance to human life.
Explain why both types of fermentation must change pyruvic acid, even though no energy is gained in this conversion.
Indicate the maximum alcohol content of Basic Kombucha fermentation, and explain the reason for this limit.
Construct a chart comparing aerobic to anaerobic respiration using at least 5 characteristics.

Vocabulary:

Aerobic: With oxygen, or living or occurring only in the presence of oxygen.alcoholic fermentation: The process for making ATP in the absence of oxygen, by converting glucose to ethanol and carbon dioxide.Anaerobic: Without oxygen; living or occurring in the absence of oxygen.Facultative anaerobe: An organism which can respire aerobically when oxygen is present, but is also capable of fermentation when oxygen levels are low.Glycolysis: The process of “splitting glucose” – stage 1 of aerobic cellular respiration and also the basis of anaerobic respiration; splits glucose into two 3-carbon pyruvates, producing 2 (net) ATP.Lactic acid fermentation: The process for making ATP in the absence of oxygen by converting glucose to lactic acid.Obligate aerobe: An organism which requires oxygen for cellular respiration.Obligate anaerobe: An organism which uses anaerobic respiration, and dies in the presence of oxygen.

Points to Consider

Humans seem to harness anaerobic respiration much more than aerobic respiration to create useful products, such as foods or fuels. Use your understanding of the two processes to explain why this makes sense.
Some controversy exists over whether or not ethanol produced by fermentation of corn is an efficient and wise way to produce fuel. Can you think of some reasons, pro and/or con?
How might the wing muscles of birds which migrate long distances compare to those of birds which do not migrate? Why do you suppose human muscles are mixtures of red and white fibers, rather than specialized, as in many birds?

Kombucha Fermentation:

Fermentation of sugared tea with a symbiotic culture of acetic acid bacteria and yeast (tea fungus) yields kombucha tea which is consumed worldwide for its refreshing and beneficial properties on human health. Important progress has been made in the past decade concerning research findings on kombucha tea and reports claiming that drinking kombucha can prevent various types of cancer and cardiovascular diseases, promote liver functions, and stimulate the immune system. Considering the widespread reports on kombucha, we recognized the need to review and update the research conducted in relation to kombucha tea, its products and tea fungus. Existing reports have suggested that the protective effects of kombucha tea are as good as those of black tea, however, more studies on kombucha tea and its composition are needed before final conclusions can be made.

Introduction

Kombucha tea is a slightly sweet, slightly acidic refreshing beverage consumed worldwide. It is obtained from infusion of tea leaves by the fermentation of a symbiotic association of bacteria and yeasts forming “tea fungus” (Chen and Liu 2000). A floating cellulosic pellicle layer and the sour liquid broth are the 2 portions of kombucha tea (Figure 1). It tastes like sparkling apple cider and can be produced in the home by fermentation using mail order or locally available tea fungus. Though green tea can be used for kombucha preparation, black tea and white sugar are considered the finest substrates. Kombucha is the internationally used Germanized form of the Japanese name for this slightly fermented tea beverage. It was first used in East Asia for its healing benefits. Kombucha originated in northeast China (Manchuria) where it was prized during the Tsin Dynasty (“Ling Chi”), about 220 B.C., for its detoxifying and energizing properties. In 414 A.D., the physician Kombu brought the tea fungus to Japan and he used it to cure the digestive problems of the Emperor Inkyo. As trade routes expanded, kombucha (former trade name “Mo‐Gu”) found its way first into Russian (as Cainiigrib, Cainii kvass, Japonskigrib, Kambucha, Jsakvasska) and then into other eastern European areas, appearing in Germany (as Heldenpilz, Kombuchaschwamm) around the turn of the 20th century. During World War II, this beverage was again introduced into Germany, and in the 1950’s it arrived in France and also in France‐dominated North Africa where its consumption became quite popular. The habit of drinking fermented tea became acceptable throughout Europe until World War II which brought widespread shortages of the necessary tea leaves and sugar. In the postwar years, Italian society’s passion for the beverage (called “Funkochinese”) peaked in the 1950s. In the 1960s, science researchers in Switzerland reported that drinking kombucha was similarly beneficial as eating yogurt and kombucha’s popularity increased. Today, kombucha is sold worldwide in retail food stores in different flavors and kombucha culture is sold in several online shopping websites. A kombucha journal is electronically published by Gunther W. Frank and available worldwide in 30 languages (Dufresne and Farnworth 2000; Hartmann and others 2000).

Kombucha tea is prepared by placing the kombucha culture (tea fungus) into a sugared tea broth for fermentation. If the kombucha culture is cultivated according to the standard recipe with black tea, sweetened with sucrose, it turns this substrate into a refreshing beverage called tea fungus beverage with high nutritive value and medicinal properties (Lončar and others 2000). The popularity of kombucha expanded like many other traditional beverages due to its beneficial effects on human health and its ease in home preparation. The amounts of tea, sugar, and tea fungus differ in different places. The standard procedure is as follows: tap water (1 L) is boiled and during boiling 50 g sucrose is stirred in. Then 5 g tea leaves is added and removed by filtration after 5 min. After cooling to room temperature (20 ºC) the tea is inoculated with 24 g tea fungus (the culture) and poured into a beaker (1 L) previously sterilized with boiling water. The growth of undesirable microorganisms is inhibited by the addition of 0.2 L previously fermented kombucha, thus lowering the pH. The beaker is covered with a paper towel to keep insects, especially Drosophila fruit flies away. The incubation is carried out at 20 ºC to 22 ºC. The optimal temperature is in the wide range of 18 ºC and 26 ºC. In the next few days, the newly formed daughter culture will start to float and form a clear thin gel‐like membrane across the available surface. This is the newly formed tea fungus available as a new layer above the old tea fungus which was inoculated to begin the fermentation. At this time, the tea will start to smell fermented and there will be gas bubbles appearing from the carbonic acid produced during the fermentation. The mother culture will remain at its original volume as it sinks to the bottom of the tea broth where it remains under the newly forming daughter culture. After 10 to 14 d, a new tea fungus will have developed on the surface of the tea as a disc of 2‐cm thickness covering the whole diameter of the beaker. The newly formed tea fungus is removed with a spoon and kept in a small volume of fermented tea. The remaining beverage is filtered and stored in capped bottles at 4 ºC (Reiss 1994). The taste of the kombucha changes during fermentation from a pleasantly fruity sour‐like sparkling flavor after a few days to a mild vinegar‐like taste after a long incubation period. It is remarkable that 50 g sucrose/L provide the optimal concentrations of ethanol and lactic acid, and this sugar concentration has been used in traditional recipes for the preparation of “teakwass” (another name for kombucha) for a long time (Reiss 1994). An optimum fermentation time is required for the production of kombucha with pleasant flavor and taste. Longer fermentation produces high levels of acids (like mild vinegar) that may pose potential risks when consumed (Sreeramulu and others 2000). Currently kombucha is alternately praised as “the ultimate health drink” or damned as “unsafe medicinal tea” (Blanc 1996; Hartmann and others 2000). There are many conception and misconception regarding the health benefits and toxicity of kombucha beverage. Though it is claimed to be beneficial for several medical ailments, very little or no clinical evidence is available for that. Studies on kombucha were reviewed earlier by Dufresne and Farnworth (2000), Yurkevich and Kutyshenko (2002), and Ernst (2003). Research on kombucha was highly boosted during the past decade, but there were no review reports published during this period. It encouraged us to collect the scientific studies reported on kombucha in the form of this review. The objective of this review was to investigate the microbiology, fermentation, composition, beneficial effects of kombucha beverage, and applications of tea fungus biomass based on the available literature.

Microorganisms of kombucha tea

Tea fungus or kombucha is the common name given to a symbiotic growth of acetic acid bacteria and osmophilic yeast species in a zoogleal mat which has to be cultured in sugared tea. According to Jarrell and others (2000), kombucha is a consortium of yeasts and bacteria. The formal botanical name Medusomyces gisevii was given to it by Lindau (Hesseltine 1965). Tea fungus is not a mushroom. That name is wrongly given due to the ability of bacteria to synthesize a floating cellulose network which appears like surface mold on the undisturbed, unshaken medium. Similarly to water‐derived kefir, the exact microbial composition of kombucha cannot be given because it varies. It depends on the source of the inoculum for the tea fermentation. One of the clearer accounts of the microbes found in kombucha starter is from Hesseltine (1965). He isolated an Acetobacter sp. (NRRL B‐2357) and 2 yeasts (NRRL YB‐4810, NRRL YB‐4882) from a kombucha sample received from Switzerland and used these microorganisms to produce kombucha tea. The most abundant prokaryotes in this culture belong to the bacterial genera Acetobacterand Gluconobacter. The basic bacterium is Acetobacter xylinum (Danielova 1954; Konovalov and Semenova 1955; Sievers and others 1995; Roussin 1996). It produces a cellulosic floating network on the surface of the fermenting liquid. The network is the secondary metabolite of kombucha fermentation but also one of the unique features of the culture (Markov and others 2001). Sievers and others (1995) reported that the microflora embedded in the cellulose layer was a mixed culture of A. xylinum and a Zygosaccharomyces sp. The predominant acetic acid bacteria found in the tea fungus are A. xylium, A. pasteurianus, A. aceti, and Gluconobacter oxydans (Liu and others 1996). Gluconacetobacter sp. A4 (G. sp. A4), which has strong ability to produce D‐saccharic acid‐1,4‐lactone (DSL), was the key functional bacterial species isolated from a preserved kombucha by Yang and others (2010). Strains of a new species in the genus Acetobacter, namely Acetobacter. intermedius sp. nov., were isolated from kombucha beverage and characterized by Boesch and others (1998). Dutta and Gachhui (2006, 2007) isolated the novel nitrogen‐fixing Acetobacter nitrogenifigens sp. nov., and the nitrogen‐fixing, cellulose‐producing Gluconacetobacter kombuchae sp. nov., from kombucha tea. An investigation by Marsh and others (2014) indicated that the dominant bacteria in 5 kombucha samples (2 from Canada and one each from Ireland, the United States, and the United Kingdom) belong to Gluconacetobacter (over 85% in most samples) and Lactobacillus (up to 30%) species. Acetobacter was determined in very small number (lower than 2%).

In addition to acetic acid bacteria there are many yeast species in kombucha. A broad spectrum of yeasts has been reported including species of Saccharomyces, Saccharomycodes, Schizosaccharomyces, Zygosaccharomyces, Brettanomyces/Dekkera, Candida, Torulospora, Koleckera, Pichia, Mycotorula, and Mycoderma. The yeasts of Saccharomyces species were identified as Saccharomyces sp. (Konovalov and others 1959; Kozaki and others 1972) and as Saccharomyces cerevisiae (Herrera and Calderon‐Villagomez 1989; Liu and others 1996; Markov and others 2001; Safak and others 2002), Saccharomyces bisporus (Markov and others 2001), Saccharomycoides ludwigii (Reiss 1987; Markov and others 2001; Ramadani and Abulreesh 2010), Schizosaccharomyces pombe (Reiss 1987; Teoh and others 2004), Zygosaccharomyces sp. (Sievers and others 1995; Markov and others 2001; Marsh and others 2014), Zygosaccharomyces rouxii (Herrera and Calderon‐Villagomez 1989), and Zygosaccharomyces bailii (Herrera and Calderon‐Villagomez 1989; Liu and others 1996; Jayabalan and others 2008b). The genus Brettanomyces was isolated by several workers. Herrera and Calderon‐Villagomez (1989) isolated Brettanomyces intermedius, Liu and others (1996) and Teoh and others (2004) isolated Brettanomyces bruxellensis, and Jayabalan and others (2008b) isolated B. claussenii. An examination of 2 commercial kombucha and 32 cultures from private households in Germany (Mayser and others 1995) showed variable compositions of yeasts. The predominant yeasts were Brettanomyces, Zygosaccharomyces, and Saccharomyces spp. Roussin (1996) determined Zygosaccharomyces and S. cerevisiae as the typical yeasts in North American kombucha. Kurtzman and others (2001) isolated an ascosporogenous yeast, Zygosaccharomyces kombuchaensis sp. n. (type strain NRRL YB‐4811, CBS 8849), from kombucha. An investigation of the physiology of Z. kombuchaensis sp. n., related to the spoilage yeasts Zygosaccharomyces lentus, clearly showed that these 2 species were not same (Steels and others 2002). Candida sp. is included in a great number of kombucha beverages. Kozaki and others (1972) isolated Candida famata, Candida guilliermondii, and Candida obutsa. In kombucha samples from Mexico, Herrera and Calderon‐Villagomez (1989) detected C. famata. Teoh and others (2004) identified Candida stellata. From a local kombucha in Saudi Arabia, Ramadani and Abulreesh (2010) isolated and identified 4 yeasts: Candida guilliermondi, Candida colleculosa, Candida kefyr, and Candida krusei. C. krusei were identified in kombucha from a district of Ankara (Turkey; Safak and others 2002).

The presence of the following was also established: Torula (Reiss 1987), Torulopsis(Konovalov and others 1959; Herrera and Calderon‐Villagomez 1989; Markov and others 2001), Torulaspora delbrueckii (Teoh and others 2004), Mycotorula (Konovalov and others 1959), Mycoderma (Konovalov and others 1959; Reiss 1987), Pichia (Reiss 1987), Pichia membranefaciens (Kozaki and others 1972; Herrera and Calderon‐Villagomez 1989), Kloeckera apiculata (Danielova 1954; Kozaki and others 1972; Safak and others 2002), and Kluyveromyces africanus (Safak and others 2002).

Chemical composition of kombucha tea

Acetic acid bacteria from kombucha produce acetic acid, as one of the main metabolites, when sucrose is used as a carbon source. Many authors determined the content of acetic acid in the beverage obtained after cultivation of kombucha on traditional substrate. Chen and Liu (2000) followed extended kombucha fermentation and determined the highest rate of 11 g/L after 30 d. The trend of acetic acid content was slow, increased with time, and then gradually decreased to 8 g/L, at the end of fermentation (60 d; Table 1). The same pattern was established by Jayabalan and others (2007) who monitored the fermentation until the 18th day on green tea (12 g/L) sweetened with 10% sucrose. The highest content was 9.5 g/L on the 15th day. Molasses was used in place of sucrose by Malbaša and others (2008a, 2008b). Kombucha fermentation on molasses produced only 50% of acetic acid in comparison with sucrose at the same stage of fermentation. This might be due to the poor growth of acetic acid bacteria on molasses. Glucuronic and gluconic acids are also major organic acids that are produced as a result of the kombucha fermentation process on traditional substrate. Lončar and others (2000) determined the glucuronic acid after kombucha fermentation on sweetened black tea. The highest amount was measured after 7, and 21 d (0.0034 g/L; Table 1). Jayabalan and others (2007) established the maximum value of 2.33 g/L D‐glucuronic acid after 12 d of fermentation. Chen and Liu (2000) determined that gluconic acid was not produced until the 6th day of fermentation. The ending concentration amounted the about 39 g/L after 60 d (Table 1). Yavari and others (2010) cultivated kombucha on sour cherry juice sweetened with 0.6%, 0.8%, and 1% sucrose. Glucuronic acid was produced in very large amounts of 132.5 g/L which was determined on the 14th day of fermentation, in substrate with 0.8% sucrose. The fermentation process was conducted at 37 °C. Yavari and others (2011) used response surface methodology (RSM) to predict the value of glucuronic acid content in kombucha beverage obtained after fermentation on grape juice sweetened with 0.7% sucrose, and the highest value was achieved after 14 d of fermentation at 37 °C. Franco and others (2006) established the presence of glucuronic (0.07 to 9.63 g/L) and gluconic (0.04 to 1.16 g/L) acids in a product obtained after kombucha cultivation on black tea sweetened with glucose (0.062% to 1.51%). Yang and others (2010) also determined the presence of gluconic acid and 2‐keto gluconic acid, after cultivation of Gluconacetobacter sp. A4 isolated from kombucha and a strain of lactic acid bacteria, on 5 g/L black tea sweetened with 10% glucose. L‐lactic acid is not a characteristic compound for traditional kombucha beverage, but it is detected and determined. Jayabalan and others (2007) examined kombucha prepared with green tea to have a higher concentration of lactic acid than kombucha prepared from black tea and tea waste material. The maximum value of 0.54 g/L was established on the 3rd day. Malbaša and others (2008a, 2008b) measured the content of L‐lactic acid after kombucha fermentation on molasses and established that it is a metabolic product present in large amounts. The presence of L‐lactic acid after kombucha fermentation on molasses can be correlated to the L‐lactic content of molasses itself which can be produced as a result of degradation of invert sugar in molasses. Molasses also contains amino nitrogen and biotin, which affect the intensity of kombucha fermentation. Citric acid is also not a characteristic metabolic product of the traditional beverage. Malbaša and others (2011) determined an average value of 25 g/L citric acid in the total acids (substrate with 1.5 g/L of black tea and 7% sucrose), and Jayabalan and others (2007) measured it only on the 3rd day of fermentation, 0.03 and 0.11 g/L, in kombucha prepared with green and black tea, respectively. Sucrose is the most common carbon source in kombucha fermentation. Its considerable amount stays largely unfermented during the process (Malbaša and others 2002a). Investigations showed that 34.06% of sucrose stays unfermented after 7 d, and after 21 d this value is 19.28% (Table 1). Chen and Liu (2000) determined that the content of sucrose linearly decreased during the first 30 d, followed by a slow‐rate decline. Malbaša and others (2008b) established that utilization of 7% sucrose from molasses reached 97%, after 14 d of fermentation. The decline of sucrose concentration is more pronounced when the concentration of sucrose in molasses is optimal (7%), compared to the systems with pure sucrose. Utilization in the samples with molasses is slow when the content of sucrose is lower (Malbaša and others 2008a, 2008b). Yavari and others (2010) concluded that sucrose utilization, after the 4th day, began to speed up and this trend continued until the 14th day when the lowest sucrose content (2.1 g/L) was determined. Malbaša and others (2002a) measured the contents of D‐glucose and D‐fructose in traditional kombucha and the highest values were 19.60 (on 14th day) and 10.25% (on 10th day), respectively. Lončar and others (2000) concluded that sucrose, glucose, and fructose were not utilized entirely after 21 d of fermentation and confirmed that fructose was metabolized before glucose. Chen and Liu (2000) established that glucose was not produced analogous to fructose (0.085%/d) but in lower amount (0.041%/d). The beverage, obtained on Jerusalem artichoke tuber extract, contained sugars in lower amount in comparison to sucrose substrate, except for D‐fructose (10.41% on 5th day). In addition to sucrose and D‐glucose, the presence of inulooligosaccharides were also determined (Malbaša and others 2002a).

Kombucha tea as an antimicrobial source

Kombucha tea has been studied by many researchers for its inhibitory activity on many pathogenic microorganisms. Tea containing 4.36 g of dry tea per liter and 10% sucrose and fermented with tea fungus showed no antibiotic activity in the beverage beyond that caused by acetic acid, a primary product of the fermentation (Steinkraus and others 1996). Kombucha tea containing 33 g/L total acid (7 g/L acetic acid) had antimicrobial efficacy against Agrobacterium tumefaciens, Bacillus cereus, Salmonella choleraesuis serotype Typhimurium, Staphylococcus aureus, and Escherichia coli, but not for Candida albicans(Greenwalt and others 1998). Kombucha tea could inhibit the growth of the pathogens Entamoeba cloacae, Pseudomonas aeruginosa, B. cereus, E. coli, Aeromonas hydrophila, Salmonella typhimurium, Salmonella enteritidis, Shigella sonnei, Staphylococcus epidermis, Leuconostoc monocytogenes, Yersinia enterocolitica, S. aureus, Campylobacter jejuni, Helicobacter pylori, and C. albicans (Sreeramulu and others 2000, 2001). Kombucha tea prepared from different substrates like mulberry tea, Japanese green, jasmine tea, oolong tea, and black tea was tested on pathogenic bacteria of humans and shrimp. Results revealed that black tea kombucha possessed the greatest inhibitory activity and Vibrio parahaemolytica showed the highest susceptibility to the fermented tea (Talawat and others 2006). Battikh and others (2012) reported that kombucha prepared from both black tea and green tea had antimicrobial potential against the tested human pathogenic microorganisms, except C. krusei, and kombucha green tea exhibited the highest antimicrobial potential. Afsharmanesh and Sadaghi (2013) reported that the body weight, feed intake, and protein digestibility of broiler chickens fed with a diet having 1.2 g/kg kombucha tea (20% concentration) were significantly increased compared to the control and green tea‐fed broilers. They suggested that kombucha tea can be an alternative to antibiotic growth promoters in the diets of broilers. Research on kombucha has demonstrated its antimicrobial efficacy against pathogenic microorganisms of both Gram‐positive and Gram‐negative origin. Antimicrobial activity of kombucha tea is largely attributable to the presence of organic acids, particularly acetic acid, large proteins, and catechins. Acetic acid and catechins are known to inhibit a number of Gram‐positive and Gram‐negative microorganisms (Sreeramulu and others 2000).

Kombucha tea as an antioxidant source

There has been a global trend toward the use of phytochemicals present in natural resources as antioxidants and functional foods. Bioactive molecules of natural resources are being utilized in the food industry, and there is evidence that these molecules can act as antioxidants within the human body. Antioxidant activity of Kombucha is correlated with its many claimed beneficial effects like cancer prevention, immunity enhancement, and alleviation of inflammation and arthritis. Jayabalan and others (2008a) reported on the free radical scavenging abilities of kombucha tea prepared from green tea, black tea, and tea waste material. They have shown that total phenolic compounds, scavenging activity on DPPH radical, superoxide radical, and inhibitory activity against hydroxyl radical‐mediated linoleic acid were increased with an increase in fermentation time, whereas reducing power, hydroxyl radical scavenging ability (ascorbic acid‐iron EDTA), and antilipid peroxidation ability were decreased. Malbaša and others (2011) studied the influence of 3 starter cultures (mixed culture of acetic bacteria and Zygosaccharomyces sp., mixed culture of acetic bacteria and S. cerevisiae, and native local kombucha) on the antioxidant activities of green tea and black tea kombucha beverage to hydroxyl and DPPH radicals. They observed the highest antioxidant activity with native kombucha on green tea beverage and acetic acid bacteria with Zygosaccharomyces sp. culture on black tea beverage. The antioxidant property of kombucha tea was tested against tertiary butyl hydroperoxide (TBHP)‐induced cytotoxicity using murine hepatocytes and showed that kombucha tea neutralized the TBHP‐induced changes and prevented cell death. These counter effects were also shown by the unfermented black tea, but the kombucha tea was found to be more efficient (Bhattacharya and others 2011b). The antioxidant activity of kombucha tea is due to the presence of tea polyphenols, ascorbic acid, and DSL. Kombucha tea was observed to have higher antioxidant activity than unfermented tea and that may be due to the production of low‐molecular‐weight components and structural modifications of tea polyphenols by enzymes produced by bacteria and yeast during fermentation. Kombucha exhibited increased free radical scavenging activities during fermentation. The extent of the activity depended upon the fermentation time, type of tea material, and the normal microbiota of the kombucha culture, which in turn determined the nature of their metabolites. Although free radical scavenging properties of kombucha showed time‐dependent profiles, prolonged fermentation is not recommended because of accumulation of organic acids, which might reach harmful levels for direct consumption. The identification of extracellular key enzymes responsible for the structural modification of components during kombucha fermentation and potent metabolites responsible for the free radical scavenging abilities are necessary to elucidate the metabolic pathway during kombucha fermentation. Metabolic manipulations may be one of the effective methods to enhance the antioxidant activities and fermentation efficiency of kombucha.

Kombucha tea as hepatoprotective agent

Kombucha tea has been studied for its hepatoprotective property against various environmental pollutants in animal models and cell lines and it has been shown that it can prevent hepatotoxicity induced by various pollutants. Kombucha tea (prepared from black tea) was tested against paracetamol (Pauline and others 2001), carbontetrachloride (Murugesan and others 2009), aflatoxin B1 (Jayabalan and others 2010a), cadmium chloride (Ibrahim 2011), TBHP (Bhattacharya and others 2011b), and acetaminophen (Abshenas and others 2012; Wang and others 2014). It was demonstrated that it can effectively attenuate the physiological changes driven by these liver toxicants. The volume of kombucha tea, number of doses, treatment period, and the method of administration used in these studies were not same. In most of the studies, male albino rats (Pauline and others 2001; Murugesan and others 2009; Jayabalan and others 2010a; Ibrahim 2011; Wang and others 2014) were used and a few other studies were conducted with Balb/c mice (Abshenas and others 2012) and isolated murine hepatocytes (Bhattacharya and others 2011a). Hepatoprotective efficacy of kombucha tea was studied by measuring liver toxicity markers (serum glutamic pyruvate transaminase, serum glutamic oxaloacetic transaminase, malondialdehyde, alkaline phosphatase, gamma glutamyl transpeptidase), reduced glutathione, antioxidant enzymes (glutathione‐S‐transferase, glutathione peroxidase, glutathione reductase, catalase, and superoxide dismutase), various levels of creatinine and urea, nitric oxide levels in liver, and by histopathological analysis of liver tissue. More recently, apoptosis, reactive oxygen species generation, changes in mitochondrial membrane potential, cytochrome c release, activation of caspases (3 and 9) and Apaf‐1 were studied to show the hepatoprotective property of Kombucha tea against TBHP (Bhattacharya and others 2011b). Antioxidant activity and its ability to facilitate both antioxidant and detoxification processes in the liver were ascribed to the hepatoprotection offered by kombucha tea. Wang and others (2014) reported that hepatoprotective effects of kombucha tea against acetaminophen is largely attributed to the presence of DSL, and Gluconacetobacter sp. A4 was the primary producer of it. Most of the studies concluded that kombucha tea could be beneficial against liver diseases, for which oxidative stress is a well‐known causative factor.

Kombucha tea as an anticancer source

Chemoprevention using a combination of dietary phytochemicals with diverse mechanisms has been proposed as a successful approach to control different types of cancer with fewer side effects. Kombucha tea has been seriously claimed to have anticancer property by kombucha drinkers for many years. Based on personal observations and testimonials, it has been claimed to have anticancer properties and has also been claimed by a population study conducted in Russia by the “Central Oncological Research Unit” and the “Russian Academy of Sciences in Moscow” in 1951 (Dufresne and Farnworth 2000). Cetojevic‐Simin and others (2008) investigated the antiproliferative activity of kombucha beverages from black tea and winter savory tea (Satureja montana L.) on HeLa cells (cervix epithelial carcinoma), HT‐29 (colon adenocarcinoma), and MCF‐7 (breast adenocarcinoma) using the sulforhodamine B colorimetric assay. They reported that the antiproliferative effect of kombucha winter savory tea was comparable to that of traditional kombucha black tea; and concluded that kombucha prepared from winter savory tea might have more active antiproliferative components than simple water extracts of winter savory tea. An ethyl acetate fraction of kombucha black tea which contained dimethyl 2‐(2‐hydroxy‐2‐methoxypropylidene) malonate and vitexin at a concentration of 100 μg/mL caused cytotoxic effects on 786‐O (human renal carcinoma) and U2OS (human osteosarcoma) cells, significantly reduced the cell invasion and cell motility in A549 (human lung carcinoma), U2OS and 786‐O cells, and reduced the activities of matrix metalloproteinase‐2 (MMP‐2) and MMP‐9 in 786‐O cells and MMP‐2 activity in A549 cells (Jayabalan and others 2011). Lyophilized kombucha tea extract significantly decreased the survival of prostate cancer cells by downregulating the expression of angiogenesis stimulators like matrix metalloproteinase, cyclooxygenase‐2, interleukin‐8, endothelial growth factor, and human inducible factor‐1α (Srihari and others 2013a). This study showed the remarkable potential of kombucha in inhibiting angiogenesis through alterations in the expression of angiogenic stimulators. The possible anticancer mechanisms of tea polyphenols accepted by most researchers now are as follows: (1) inhibition of gene mutation; (2) inhibition of cancer‐cell proliferation; (3) induction of cancer‐cell apoptosis; and (4) termination of metastasis (Conney and others 2002; Ioannides and Yoxall 2003; Park and Dong 2003). Anticancer properties of kombucha tea might be due to the presence of tea polyphenols and their degradation products formed during fermentation.

Module 2 – The Art of Advanced Fermentation & The Science of Gut Microbiota, Probiotics, Prebiotics, Synbiotics & Psychobiotics.

What is fermentation?

At the most basic level, fermentation is the transformation of food by microorganisms — whether bacteria, yeasts, or mold. To be slightly more specific, it is the transformation of food through enzymes produced by those microorganisms. And finally, in the strictest scientific definition, fermentation is the process by which a microorganism converts sugar into another substance in the absence of oxygen. The word fermentation comes from the Latin word fervere, meaning “to boil.” The ancient Romans, upon seeing vats of grapes spontaneously bubble and transform into wine, described the process using the closest analogue they could think of. And while those bubbling vats of grapes had nothing to do with boiling, they were true ferments in the scientific sense, as yeast-produced enzymes transformed the sugars in the grapes into alcohol. However, not all the processes we consider to be fermentation fit neatly into tidy definition of it. For instance, while koji is faithful to the definition, garums are not. In koji, the mold Aspergillus oryzae penetrates grains of rice or barley and produces enzymes that convert the grain’s starches into simple sugars and other metabolites. This is what’s known as a primary fermentation process. Miso, on the other hand, are the product of a secondary fermentation process. To produce miso, we mix koji with plant proteins in order to take advantage of the enzymes produced during the primary fermentation process.

What makes fermentation delicious?

Taste is a function of the human body, and to undertand what tastes good to us, we have to understand its role in our evolutionary history. Al our senses serve to aid in ur survival. Our senses of taste and smell have been shaped over hundreds of millions of years to incentivize us to eat foods that are beneficial to our bodies. Our tongues and olfactory system are unbelievably complicated organs that take in chemical cues from the world around us and transmit that information to our brains. Taste lets us know that a ripe piece of fruit is sweet and thus full calorie-rich sugar, or that a plant’s stalk is bitter and potentially poisonous. We are born with aversions to certain flavors (a sense that becomes reinforced by experience), leading us to gag at the stench of rotting flesh decaying at the hands of pathogenic bacteria, while we register the scent of beans heating over a fire as mouthwateringly delicious, because it indicates to our brains that we’re about to eat something rich in proteins. there are numerous biological processes at work in any given fermentation, but the ones that matter most to us from a taste perspective are those that break down large chains of molecules into their constituent parts. The starches in foods like rice, barley, peas, and bread are actually long chains of linked molecules of glucose, a simple sugar. Proteins, which can be found in large supply in soybeans , are constructed in a similar fashion from lengthy, winding chains of amino acids — small organic molecules essential to all aspects of life on earth. One of those amino acids, glutamic acid, registers on our taste receptors as umami — the elusive, craveable quality that connects foods like mushrooms, tomatoes, cheese, and soy sauce.

So what makes fermentation so good?

On their own, starch and protein molecules are too large for our bodies to register as sweet or umami-rich. However, once broken down into simple sugars and free amino acids through fermentation, foods become more obviously delicious. Koji made from rice has an intense sweetness that plain cooked rice doesn’t. Simply put, the microbes responsible for fermentation transform more complicated foodstuffs into the raw material your body needs, rendering them more easily digestible, nutritioous and delicious. Our affection for the tastes those mirobes produce has allowed them to evolve and stay in our company. Humans have been fermenting for so long that many of the microscopic agents responsible can be considered domesticated, just like household cats or dogs. But while pets can stare longingly at you if they’re hungry or cold, microbes are a bit trickier to read. It’s a mutually beneficial relationship, but one that needs a bit of work to keep everyone happy. That’s the job of the fermenter.

Setting the table for Microbes:

There’s a thin line between rot and fermentation and that line might best be understood as an actual line, like the kind you’d find outside a nightclub. Rot is a club where everyone gets in: bacteria and fungi, safe or unsafe, flavor enhancing or destructive. When you ferment something, you’re taking on the role of a bouncer, keeping out unwanted microbes and letting in the ones that are going to make the party pop. You have several tools at your disposal in trying to encourage certain microbes or deter others. Some organisms are more tolerant of acidity than others. Likewise with oxygen, heat and salinity. If you’re familiar with what your preferred microbe needs to function, you can wield these factors to your benefit.

Conclusion

Given the close symbiotic relationship existing between the gut microbiota and the host, it is not surprising to observe a divergence from the normal microbiota composition (generally referred to as dysbiosis) in a plethora of disease states ranging from chronic GI diseases to neurodevelopmental disorders . The application of metabolomics approaches has greatly advanced our understanding of the mechanisms linking the gut microbiota composition and its activity to health and disease phenotypes. At a functional level, a potential way to describe a ‘dysbiotic microbiota’ might be one which fails to provide the host with the full complement of beneficial properties. Whether dysbiosis of the microbiota is a cause or a consequence of the disease is therefore likely to exacerbate the progression of the disease and affect the type of strategies needed to restore symbiosis. Depending on the type and stage of disease, these include the development of microbiome modulators (e.g. antimicrobials, diet, prebiotics, probiotics and psychobiotics) mostly aimed at changing the composition of the host microbiota, or of microbial-based solutions to replace some of the defective microbes and their associated benefits (e.g. specific commensal strains, probiotics, defined microbial communities, microbial-derived signalling molecules or metabolites). Given the contribution of host genetics in many diseases associated with a dysbiotic microbiota, dual therapeutic strategies (e.g. combining immunotherapy such as lifestyle medicine and microbiota-targeted approaches) may also be required to restore the environment required to re-establish an effective communication between the host and the targeted microbiota. Success in these endeavours is dependent on our mechanistic understanding of how the microbiota affects and is affected by the host at a molecular and biochemical level.

Useful Fermentation Terms:

Back slopping

Mesophilic culture – Bacteria thrive at 20 – 45C

Anaerobic respiration

Biofilm

Thermophilic culture – Bacteria thrive at 45 – 122C

Obligate anaerobic

Isothiocyanates produced and activated via fermentation – Inhibit cancer cells

Kombucha researchers – Len Porzio, Gunther W Frank and Michael Roussin

Microbiology – Pasteur and Liebig

Kombu (Korean Physician) cha (Tea)

Advanced Gut Health:

Lack of fibre and lack of good bacteria is a huge issue for vegans and non vegans. Also the rise in C. section birthing, bottle feeding rather than breast feeding and heavy use of antibiotics.

Check your microbiome at ubiome.com (The gut explorer kit)

A healthy diverse community will extract and synthesise many more nutrients and for raw vegans will potentiate the powderful phytochemicals in our colorful plants, all of which have anti cancer properties. Fermenting these colorful vegetables such as kimchi and sauerkraut enhances phytochemical potential and develops further phytochemical composition such as isotheocyonates which supress cancer growth.

The firmicutes and bacteroids:

Fermentation is the harvesting and culturing of a certain group of microbes which play a major role in the prevention of illness, the feeling of wellbeing and in our pursuit of gastrointestinal homeostasis. To prevent chronic illness and autoimmune disorders we need to give our GI-tract balance in the favour of good bacteria such as Lactobacillus and Bifidus bacterium. Ultimately avoiding a dysbiosis of the gut which is where a pathogen becomes dominant largely because of lack of diversity in our microbial community.

Major contributers to Gut Health (Blue zones):

* Exercise (Movement)
* Fermented foods rather than probiotics
* Prebiotic foods such as inulin, onions, green banan, leeks, oats
* Fibre – beans, lentils, grains (Not all juicing)

Major contributers to dysbiosis:

Antibiotics, poor diet, excessive stress, anxiety, brain injury, autism, vaccinations, C. section birth, Ptsd (perception of threat & dorsal vagal)

Advanced fermentation notes:

In complex causes such as chrons disease or IBS etc or other autoimmune disorders Fermented foods play a major role in recovery but often just a role not necessarily leading role or only role. Exercise, pro social behavior, movement and fibre are also important as adjunctive to parasympathetic inducing therapies such as somatic psychotherapy, psychodynamic psychotherapy and mindfullness. FMT – Fecal Matter Transplant (Over 90% success) may be also an option.

The war against microbes:

Louis Pasteur and Ignaz Semmelweis

In 1847 Ignaz proposed that the spread of harmful bacteria from corpes was being spread to mothers giving birth by Doctors not washing hands which was contributing to a huge number in deaths associated to child labour. In 1865 he died in a mental institution. In 1880 Louis Pasteur – a french biologist was one of the founding fathers of the Germ theory, this confirming Ignaz theories. This was also the birth of The hygiene hypothesis.

The Hygiene Hypothesis and the Germ Theory:

The germ theory of disease is the current accepted scientific theory for many diseases which states that microbes, specifically pathogens can lead to disease. As a result of the germ theory, we have declared a war on microbes such as daily showers, sanitisers, not allowing children play in dirt etc. The hygiene hypotheis first published in 1989 proposes that lack of exposure to diverse microbes as a child sets up a compromised immunesystem thus a precurser to many illnesses.

Microbes and pathogens also have receptor sites for neurotransmitters speaking directly to the brain via the vagus nerve influencing behaviour. A good example of pathogens that evoke sick behaviour in cases of IBS: If we stay at home and remove our exposure to good bacteria in way of touch and social contact then the pathogen has better chance of staying dominant (Theory).

High stress events activate sympathetic nervous system as a stress response bringing blood supply away from gut and into the limbs for action, an extreme of this is the Freeze response which is dorsal vagal and damaging to the viscera, heart, lungs, GI-tract over extended periods. A healthy vagal tone is parasymphatic which is relaxed nervous system, ventral vagal, pro social, healthy digestion of food and life events. So with PTSD or childhood trauma where even a perception of threat can bring someone into stress response or dorsal vagal freeze response such as returning veterans, then we see major gut disorders. Complex to treat.

Specific Recipes Covered:

Kimchi
Kombucha
Sauerkraut
Pickles (onions, cucumber, peppers, beetroot)
Kvass
Kefir
Buckwheat yogurt
Yogurt (soy, sunflower, nut, coconut, buckwheat)
Tepeche
Cheese (sesame, sunflower, hemp, nut)
Miso (koji)
Apple cider vinegar
Fermented porridge
Smreka

Other Topics Discussed in Class :

Discuss brief history of bacteria – Ignaz in 1847, Louis Pasteur in 1880 and up to 2008 with the human mirobiome project.

(The war against bacteria —-> Bacteria influencing behavior)

The germ theory and hygiene hypothesis

The microbiome is the second nervous system called enteric nervous system which engages in bidirectional communication with the central nervous sytem, this is calldd The Gut-Brain Axis (GBA).

There is a major nerve that plays in this called the vagus nerve.

The pursuit of gastrointestinal homeostasis.

The majority of bacteria in the GI track (mouth to anus) belongs to two families; The Firmicutes and Bacteroides.

Bacteria also have receptor sites for neurotransmitters, meaning signals of stress sent via brain/nervous system influence the function of components of the microbiota.

Talk about the example of running from extreme threat.( trauma and the nervous system and kindling )

Internal/external stressors including perceptions of threat has the biggest effect of the gastrointestinal homeostasis – such as with trauma/PTSD where the body continues to experience threat.

Too much cortisol IBS now considered a microbiome-GBA disorder.

Mental health now is also seen as the health of the gut.

Psychobiotics – certain bacteria that when consumed confer mental health benefits through interactions with commensual gut bacteria.

Treat depression with bottom approach rather than top down. Kimchi, yogurt, kombucha, kefir and sauerkraut.

The human microbiome project launched in 2008 in United States to test how changes in human microbiome as associated with human health and disease.

American gut/British gut project allows you to participate in at gut study, you send money – they send kits – you send samples – they send you analysis and comparing your results with others.

Fecal transplant – 90% Success rate – In Chinese medicine this has been practiced for 1500 years (swallowing small doses of fecal matter)

Website – The power of poop – Facebook group Sally Brown.

1% of our genes are human, 99% of our genes are microbial genes.

Ignaz Semmelweis – Washing hands in 1847 to avoid spread of infectious disease. Died in 1865 after two weeks in a mental institution after almost 20 years trying to convince the medical community about spread of germs.

Louis Pasteur – Germ theory 1880 confirming Semmelweis was correct.

1646 – Athanaswis Kircher – Observe micro organisms
1665 – Robert Hooke – Observe fruiting bodies of moulds
1676 – Anton Van Leewenhoek – Observe bacteria and microorganisms

Ferdinand Cohn, Robert Koch and Louis Pasteur were pioneers in bacteriology – a later subdiscipline of microbiology.
Late 19th century – Martinus Beijerinck and Sergei Winogradsky reveal the true Breadth of microbiology – viruses

Felix d’Herelle – bacteriophages

Joseph Lister – Phenol disinfectant for open wounds

Koji – Aspergillus Oryzaee

Prebiotic – Inulin, onions, leeks, garlic, Jerusalem artichoke, asparagus, oats, green bananas, chicory, dandelion root, greens, cassava, raw collards

Probiotics: Pro Bios – For Life

In 1770 James Cook eliminated scurvy which was responsible for huge deaths, by giving his crew sauerkraut.

Fermentation dates back to Naolithic times 10,200 BC

Fermentation comes from word Fervere which means ‘to boil’ or to agitate bacteria to produce alcohol and fermentare which means to leaven – to rise.

First evidence of alcohol was in China 7000 BC which was grapes, hawthorn berries, honey and rice.

Wild fermentation VS lacto fermentation

Fermentation dates back to Naolithic times 10,200 BC

Fermentation comes from word Feversse which mean ‘to boil’ or to agitate bacteria to produce alcohol

First evidence of alcohol was in China 7000 BC which was grapes, hawthorn berries, honey and rice

Hans and Eduard Beuchner 1897

Microbiology 1500’s

Kombucha research (Len Porzio, Michael Roussin, Gunther W Frank

Annie 086 389 8050 or Adrienne 086 826 8033 Colonics

100 Trillion microbiome in our bodies (10 times the cells)

2/3 kilos in weight

90% of our DNA is microbiome DNA

1000 different types

50/60 grams of sugars needed daily to keep gut healthy

60% of your stool is bacteria (Alive and dead)

Need 12g or prebiotics per day (1 onion is 100g)

The gut is the GI Gastrointestinal Tract (The inner tube of life)

it is a tube connecting mouth to anus about 9 metres. The gut is a bio reactor.

The Microbiota = All microorganisms that live in the gut

The Microbiome = All microbes + all the other genes combined

We have 10 Trillion cells in our bodies but we have 10 times more microbes at around 100 trillion. About 99% of the DNA in our bodies is microbial DNA.

There about 1000 different species of microbes in our bodies which would way about 2-3 kilos. These microbes need about 50/60 of sugars to stay healthy each day.

As a byproduct of this metabolism, we expel gas, between 1-4 litres of gas daily. We then remove waste through our stools which is made up of about 60% bacteria live and dead.Gut Repair Protocol
Eat for beauty – Remove toxins – Nourish cells – Balance hormones – Overcome stress

Further Recipes to Discuss

Dahi – Indian ferment

Vegan Dahi:
Seed mylk
Lemon juice
Spice
Pickled tofu

Natto Recipe

Wash and soak 4 cups of soybeans for 9 hours. Drain and pressure, cook for 12 minutes or on cooker for 9 hours. Then drain. Dissolve one spoonful of Natto spores into two teaspoons of sterilized water. While beans are still warm poor the Natto spore solution over the beans and stir. Place in a shollow tray covered with —- cloth and put in dehydrator at 100 farenheit for 22/24 hours.

Advanced Cheese Recipe

Nettle rennet
Probiotic capsule
Sunflower
Kefir
Other flavours

Heat on double boiler up to 30 degrees, stir until coagulation occurs then follow normal process. Create rind by washing with miso bine

The Psychobiotic Revolution by Ted Dinan

It may be possible to relieve anxiety and depression solely by manipulating bacteria in the gut.

Psychobiotics are defined as live bacteria and their food (probiotics & prebiotics) which, when ingested, confer mental health benefits through interactions with commensal gut bacteria. Ninety percent of what we lug around with us is not human. It’s microbial, and it’s vital to our health, our moods, even the decisions we make. There are roughly 15 trillion cells in our body—and over 100 trillion bacteria, most of them in the gut and most of them supporting such essential functions as digestion, immunity, metabolism, even mental health in ways that are only now being understood. The body is an ecosystem of interdependent parts relaying messages to each other, explains Ted Dinan, a psychiatrist at the University of Cork, Ireland. So influential are the thousands of species of gut flora on health that Dinan aims to harness the power of microbes to treat depression. Recently, he coined a term for the live organisms in the gut that are psychoactive and of potential benefit to those suffering from a variety of psychiatricillnesses—psychobiotics. Not only can researchers now discern which strains of gut bacteria affect the nervous system, they can also map the exact pathways through which specific gut bacteria influence the brain. Although there are many preparations of bacteria now being marketed as probiotics, “the vast majority do nothing for us,” Dinan insists. “Most don’t make it past the stomach acid. But a few have enormous implications for the future of psychiatric medication.” It’s long been known that the stresssystem is intimately involved in depression. People suffering from major depression frequently have elevated levels of the hormone cortisol, released in response to stress. In a recent study, a probiotic cocktail ofLactobacillus helveticusandBifidobacterium longumwas found to reduce cortisol levels. Many physiological and psychological processes associated with depression can be traced to a deficiency in the neurotransmitter GABA. Lack of GABA in the brain may bring on the negative ruminations long linked with depression. Researchers have identified gut microbes that actively secrete GABA. Chief among them are strains of Lactobacillusand Bifidobacterium. Interestingly, consuming dark chocolate leads to an increase in both bacterial families. The rich reservoir of polyphenols in chocolate acts as a prebiotic, enhancing the growth of beneficial bacteria already in the gut. A number of microbes are capable of producing other neurotransmitters, such as norepinephrine, serotonin, and dopamine. Taking Bifidobacterium infantisas a probiotic, for example, alters levels of serotonin—just like Prozac. At MIT, a teamof biologists has shown that a specific strain ofLactobacillus reuteri,delivered in either yogurt or in supplement form, improves mood, appearance, and general health by increasing levels of oxytocin, the hormone that kicks in when you cuddle, hug, or have sex. Other microbes act directly on nerve-cell receptors to influence brain states. Lactobacillus acidophilus—commonly found in yogurt, sauerkraut, and kimchi—improves the functioning of cannabinoid receptors in the spinal cord. The receptors are critical to regulating pain. “It might be time to start thinking about treating depression from the bottom up instead of the top down,” says neuroscientist Jane Foster of McMaster University, who leads a team studying depression. “The evidence is there thatthe brain is responding to the gut. Let’s make that the therapeutic pathway.” B. infantis, L. reuteri,and several other strains of gut bacteria also work throughout the immune system by attacking inflammation, a hallmark of depression. The microbes also influence appetite, sending satiety signals to the brain by increasing levels of the hormone leptin and suppressing ghrelin. Psychobiotics affect the brain through several distinct pathways. The primary route is via the vagus nerve, a central conduit that relays messages from the intestines to the brain and touches many organs in between. Neurotransmitters produced by gut microbes activate the vagus nerve in specific ways, some by altering the neuralresponse to reward. Lactobacillus rhamnosus,a strain of bacteria that reduces anxiety and depression, acts on the brain only via the vagus nerve. In the brain, it beefs up production of GABA receptors. Several strains of gut flora improve mood by way of the endocrinesystem, which is responsible for our response to stress. Some, likeB. infantis and L. reuteri, work on the immune system, where they suppress proinflammatory cytokines. The L. helveticusandB. longumcocktail operates through the neuroendocrine system to lower cortisol. Further, it curbs inflammation. Some microbes are crucial digestively for fermenting fibrous food; the process yields short-chain fatty acids that enter the bloodstream and, once in the brain, regulate appetite. Therapeutic psychobiotics are a long way from reaching the market; still, it’s possible to unleash some of the power of microbes. There are active agents in yogurt that reduce anxiety and fear, studies show. Eating fermented foods—kefir, sauerkraut—also supplies psychobiotics. Take a cue from Stanford microbiologist Justin Sonnenburg, a pioneer in the therapeutic use of gut bacteria, who ferments his own kimchi. “These microbes,” he says, “could change public health.”

Scientifically Validated Psychobiotics

B. longum(1714) – Reduce stress and inflammation. Found in yogurt, kefir and sauerkraut.
B. infantis(35624) (Same as B. longum) .Found in yogurt, kefir and sauerkraut.
L. helveticus .Found in yogurt, kefir and sauerkraut.

B. breve(1205) – Reduces anxiety and prevents candida
B. animalis – Treats IBS and colitis
B. animalis lactis – Enhances PMN phagocytic capacity and NK cell tumoricidal activity boosting immune system.

B. bifidumalong with L. acidophilusand L. casei for eight weeks has been proven to alleviate depression.

L. acidophilus – Treats SIBO. High amounts found in yogurt, kefir and sauerkraut. This Bacteria is also used to treat anxiety.

L. bulgaricus/ L. helveticus – Improves immune function and moderate the response to emotional stimuli. Found in kefir & yogurt.

L. rhamnosus – Reduce anxiety and depression.
L. rhamnosus GG (LGG) – Treats IBS.

S. boulardi– Treats IBS, Colitis and Crohn’s.
L. reuteri – Reduces antibiotics and Reduces hunger.
L. plantarum – Reduces IBS, support bowel, improve memory – Found in pickles and kimchi.
L. casei – Mood enhancer, reduces anxiety & good for chronic fatigue syndrome – Found in yogurt.
L. paracasei – Counter effects of alcohol and antibotics.
S. thermophilus – Syngerstic with L. delbruekii– for treating anxiety. Found in kefir and yogurt.

Rhizopus Microsporus& Klebsiella Pneumoniae Subsp. Ozaenaefound in Tempeh has the following bioactive compounds and functional properties:

Antioxidant genestein, daidzein, tocopherol, superoxide dismutase

Prevents oxidative stress causing non-communicable disease such as hyperlipidemia, diabetes, cancer (breast and colon), prevents the damage of pancreatic beta cell

Astuti, 2015

Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevisfound in Sauerkraut has the following bioactive compounds and functional properties:

Vitamin C		Treats and prevents Scurvy	Peñas et al., 2013
Glucosinolates		Activation of natural antioxidant enzymes	Martinez-Villaluenga et al., 2012

B. Subtilisfound in Natto has the following bioactive compounds and functional properties:

Nattokinase, antibiotics, Vitamin K

Antitumor and Immunomodulating

Nagai, 2015

L. Kimchii, E.Faecalis, Lb.Brevis, P. Cerevisiae and Lb. Plantarum– Species found in fermented root vegetable dish Kimchi has been the follwoing bioactive compounds and functional properties:

Isocyanate and sulphide indole-3-carbinol	Prevention of cancer, detoxification of heavy metals in liver, kidney, and small intestine	Kwak et al., 2014
Ornithine	Anti-obesity efficacy	Park et al., 2012
Vitamin A, Vitamin C, fibers	Suppression of cancer cells	Han et al., 2015
Capsaicin, Allicin	Prevention of cancer, suppression of Helicobacter pylori	Lim and Im, 2009
Chlorophyll	Helps in prevention of absorbing carcinogen	Ferruzzi and Blakeslee, 2007
S-adenosyl-l-methionine (SAM)	Treatment of depression	Lee and Lee, 2009
HDMPPA (an antioxidant)	Therapeutic application in human atherosclerosis

Kombucha Probiotics: Bacteria & Yeast

The specific bacteria and yeast strains in the kombucha are what make it act the way it does, and what produce the fizz and flavor of kombucha. Not all kombucha cultures will contain the exact same strains, but these are some that have been recorded in studies:

Acetobacteris an aerobic (requiring oxygen) bacteria strain that produces acetic acid and gluconic acid. It is always found in kombucha. Acetobacter strains also build the scoby mushroom. Acetobacter xylinoides and acetobacter ketogenum are two strains that you might find in kombucha.
Saccharomycesincludes a number of yeast strains that produce alcohol and are the most common types of yeast found in kombucha. They can be aerobic or anaerobic (requires an oxygen-free environment). They include Saccharomycodes ludwigii, Saccharomycodes apiculatus, Schizosaccharomyces pombe, Zygosaccharomyes, and Saccharomyces cerevisiae.
Brettanomycesis another type of yeast strain, either aerobic or anaerobic, that are commonly found in kombucha and produce alcohol or acetic acid.
Lactobacillus: A type of aerobic bacteria that is sometimes, but not always, found in kombucha. It produces lactic acid and slime.
Pediococcus: These anaerobic bacteria produce lactic acid and slime. They are sometimes, but not always, found in kombucha.
Gluconacetobacter kombuchaeis an anaerobic bacteria that is unique to kombucha. It feeds on nitrogen that is found in tea and produces acetic acid and gluconic acid, as well as building the scoby.
Zygosaccharomyces kombuchaensisis a yeast strain that is unique to kombucha. It produces alcohol and carbonation as well as contributing to the mushroom body.

Kombucha also contains a variety of other nutrients, particularly various acids and esters that give the drink its characteristic tang and fizz. Included in these components is gluconic acid, which is the primary difference between the makeup of kombucha and the makeup of apple cider vinegar. The actual bacteria, sugar, and acid content of kombucha depend on many factors, including the initial culture, the type of tea used, the type of sugar used, the strength of the tea, the type of water, the brewing time, the culturing temperature, and more. Due to the nature of kombucha, it is not possible to state an exact microbial composition for Kombucha. While different SCOBYs may vary in their exact makeup, what is common to all kombuchas is gluconic acid, acetic acid, and fructose.

Probiotics

Probiotics are live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut. They are also called “friendly bacteria” or “good bacteria.” Probiotics are available to consumers mainly in the form of dietary supplements and foods. There is mounting evidence that probiotics can have beneficial effects on human health. Possible mechanisms under active investigation include altering the intestinal “microecology” (e.g., reducing harmful organisms in the intestine), producing antimicrobial compounds (substances that destroy or suppress the growth of microorganisms), and stimulating the body’s immune response. Probiotics commonly used include Lactobacillus and Bifidobacterium.

Food Rich in Probiotics include Kefir, Kombucha, yogurt, Kimchi, Sauerkraut, Tempeh, Pickled fruits and vegetables, fermented Sauces and fermented nut & seed cheeses. Flavonoids such as polyphenols which are present in large amounts in Raw Chocolate have been shown in scientific studies to increase gut microbiome.

Prebiotics

Prebiotics are a dietary fibre that trigger the growth of bacteria having favourable effects on the intestinal flora. A prebiotic effect occurs when there is an increase in the activity of healthy bacteria in the human intestine. The prebiotics stimulate the growth of healthy bacteria such as bifidobacteria and lactobacilli in the gut and increase resistance to invading pathogens. This effect is induced by consuming functional foods that contain prebiotics. These foods induces metabolic activity, leading to health improvements. Healthy bacteria in the intestine can combat unwanted bacteria, providing a number of health benefits. The most common type of prebiotic is from the soluble dietary fibre inulin.

Inulin is common in many plants containing fructan. Furthermore, many of these plants are frequently eaten as vegetables – asparagus, garlic, leek, onion and artichokes are an excellent source of inulin. Dr. David Perlmutter in his fantastic Brain Maker book suggest we should consume 12 grams of prebiotic daily. To get 12g of prebiotic you would need for example 140g of raw onion , a small onion is 70g, medium is 110g and large is 150g. One Raw Onion per day is a great way to ensure prebiotic intake.

Synbiotics

Synbioticsrefer to food ingredients or dietary supplements combining both probiotics and prebiotics. A good example of this would be adding asparagus or onion to a kimchi or a slightly green banana to a yogurt.

Psychobiotics

Psychobiotics are defined as live bacteria and their food (probiotics & prebiotics) which, when ingested, confer mental health benefits through interactions with commensal gut bacteria. A number of microbes are capable of producing other neurotransmitters, such as norepinephrine, serotonin, and dopamine. Taking Bifidobacterium infantisas a probiotic, for example, alters levels of serotonin—just like Prozac. At MIT, a teamof biologists has shown that a specific strain ofLactobacillus reuteri,delivered in either yogurt or in supplement form, improves mood, appearance, and general health by increasing levels of oxytocin, the hormone that kicks in when you cuddle, hug, or have sex. Other microbes act directly on nerve-cell receptors to influence brain states. Lactobacillus acidophilus—commonly found in yogurt, sauerkraut, and kimchi—improves the functioning of cannabinoid receptors in the spinal cord. Find more about psychobiotics in greater detail in the Psychobiotic section of the module notes.

Bacteria Strains:

Acetobacter orientalisis a bacteria strain native to Indonesia. It lowers the pH of the milk, and also produces gases during fermentation. It was first identified in Japan in what is known as Caspian Sea yogurt (also known as matsoni).

Lactobacillus acidophilusbreaks down lactose and produces lactic acid as its sole product. L. acidophilus occurs naturally in the human digestive system and other parts of the body.

Lactobacillus delbrueckii subsp. bulgaricusbreaks down lactose to produce lactic acid, which lowers the pH of milk and causes the protein to coagulate. It cannot ferment any sugar other than lactose.

Lactococcus lactis subsp. cremorisis a variety of lactococci that has a pronounced ability to develop flavor in the foods it ferments. It digests lactose and produces lactic acid, lowering the pH of milk and allowing the milk protein to coagulate. It produces a characteristic gel- like polysaccharide that is typical of viili yogurt.

Lactococcus lactisdigests lactose and produces lactic acid, lowering the pH of milk and allowing the milk protein to coagulate. It can also be used to ferment vegetables and grains as well as non-dairy milks.

Lactococcus lactis subsp. lactis biovar. diacetylactisdigests lactose and produces lactic acid, lowering the pH of milk and allowing the milk protein to coagulate. It has a tendency to dominate over other lactococci. This bacteria produces a characteristic buttery flavor and aroma in the milk products it ferments.

Leuconostoc mesenteroidesis a mesophilic bacteria strain known for producing a sour taste and a gel-like texture. It’s generally found on crop plants, and can also be used to ferment vegetables. It also speeds up the process of acidification in milk and promotes an anaerobic (no oxygen) environment, which inhibits pathogenic bacteria.

Leuconostoc mesenteroides subsp. cremorisis a mesophilic bacteria strain that is often used to produce aroma during the culturing process.

s.lactis var. bollandicus, along with S. taette, is used to make piimä, a cultured milk that is often considered to be a type of yogurt. It produces a sour flavor.

Streptococcus thermophilusbreaks down lactose, producing lactic acid, lowering the pH of the milk and causing the protein to coagulate. By law, in order to be sold as “yogurt” a product must include this bacteria strain.

s. taette, along with S. lactis var. bollandicus, is used to make piimä, a cultured milk that is often considered to be a type of yogurt. S. taette produces a sour flavor and a viscous texture.

The Brain Gut Axis By Dr Datis Kharrazian

Immune system

An infection can be seen as a battle between the invading pathogens and the host. Our bodies are equipped to fight off invading microbes that may cause disease. These are called our natural defences. An infection can be seen as a battle between the invading pathogens and the host. Our bodies are equipped to fight off invading microbes that may cause disease. These are called our natural defences.

First line of defence

The first line of defence is non–specific and aims to stop microbes from entering the body. The skin and mucous membranes act as a physical barrier preventing penetration by microbes. If the skin is cut then the blood produces a clot which seals the wound and prevents microbes from entering. The surfaces of the body – the skin, digestive system, and the lining of the nose – are covered by a community of microbes called the normal body flora. They help to protect a host from becoming infected with more harmful micro-organisms by acting as a physical barrier. The normal body flora colonises these linings which reduces the area available for pathogens to attach to and become established. It also means that the harmful microbes have to compete with the normal body flora for nutrients. The average human gut contains around 1 kg of these good bacteria which is equivalent to one bag of sugar. The respiratory system – the nose and passageways leading to the lungs – is lined with cells that produce sticky fluid called mucus that traps invading microbes and dust. Tiny hairs called cilia move in a wave-like motion and waft the microbes and dust particles up to the throat, where they are either coughed or sneezed out or swallowed and then passed out of the body in faeces. The body produces several antimicrobial substances that kill or stop microbes from growing. For example the enzymes in tears and saliva break down bacteria. The stomach produces acid which destroys many of the microbes that enter the body in food and drink. Urine as it flows through the urinary system flushes microbes out of the bladder and urethra.

Second line of defence

If microbes do manage to get inside the body then the second line of defence is activated. This is also non-specific as it stops any type of microbe. Phagocytes are a type of white blood cell that move by amoeboid action. They send out pseudopodia which allows them to surround invading microbes and engulf them. Phagocytes release digestive enzymes which break down the trapped microbes before they can do any harm. This process is called phagocytosis.

How Early-Life Stress Could Increase Risk Of Anxiety And Depression Later In Life

Being a stressed-out kid can affect the bacteria in your gut — which can set you up for mental health problems down the line.

The trillions of organisms living in your digestive tract can literally change the way your brain works. Scientists continue to find more and more evidence of the significant influence of gut bacteria on mental health. Studies have linked gut bacteria imbalances to a host of health issues, including depression, anxiety, autism and Alzheimer’s disease, and research has also suggested that a healthy microbiome can contribute to a healthy brain and good mood. These issues can be activated at a very young age. New research suggests that a stressful childhood might set you up for gut dysfunction and mental health issues down the road. In a study on mice, which was published this week in the journal Nature Communications, researchers from McMaster University in Canada showed that early-life stress can lead to imbalances in the gut microbiome and contribute to the development of anxiety and depression. “Early life stress changes the composition and metabolic activity of bacteria in the gut,” the study’s lead author, Dr. Premysl Bercik, a professor of gastroenterology at the university’s medical school, told The Huffington Post in an email. “We postulate that this change is due to altered gut function induced by stress.”

The stress-bacteria connection

For the study, the researchers subjected infant mice to stress by separating them from their mothers when they were between 3 and 21 days old. After being subjected to maternal separation, the mice had abnormally high levels of the stress hormone corticosterone and displayed anxiety and depression-like behavior. The mice also showed imbalances in gut bacteria, which the researchers attributed to the release of acetylcholine, a neurotransmitter involved in the stress response that communicates between the body and the brain. Then, the researchers repeated the experiment in a germ-free condition where the mice were not exposed to any bacteria. This time, mice also showed high stress-hormone levels and gut dysfunction after being subjected to stress, but they didn’t show any signs of anxiety or depression. When those same mice were colonized with bacteria, however, they began showing signs of anxiety and depression within a few weeks.What does it all mean? Imbalanced bacteria alone wasn’t enough to bring on anxiety and depression. Instead, the findings suggest that the interaction of bacteria and early-life stress may be what determines an individual’s likelihood of developing anxiety and depression. “We are starting to explain the complex mechanisms of interaction and dynamics between the gut microbiota and its host,” Bercik said in a written statement. “Our data show that relatively minor changes in microbiota profiles … can have profound effects on host behaviour in adulthood.”

Happy gut, happy brain

How does it work? The brain and the gut communicate via gut-brain axis, a mode of bidirectional signaling between the digestive tract and the nervous system. There are several central mechanisms by which gut bacteria can communicate with the brain. First, imbalances in gut bacteria can trigger inflammation by increasing the permeability of the intestinal lining, which allows toxins to seep into the bloodstream. Research has linked pro-inflammatory markers (cytokines) and increased intestinal permeability with anxiety and depression. Secondly, bacteria can produce neurotransmitters, which are carried through the blood to the brain. Bacteria can also stimulate specific nerves in the gut that then transmit information to the brain, Bercik said. Fortunately, you can support gut health (and therefore mental health) by eating a diet that’s rich in probiotics — the “friendly” gut bacteria that support digestion and a balanced microbiome, and are known to boost immune and neurological function.

Disruption of intestinal microbiota homeostasis (dysbiosis) has been associated with these diseases (show below). In addition, dysbiosis can be caused by environmental factors commonly encountered in Western societies, including diet, genetics, disruption of circadian rhythms, and alcoholic beverage consumption. Dysbiosis also can be prevented or treated with probiotics, probiotic rich foods and prebiotics.

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