Lesson 16: Vitamin C
Vitamin C
Vitamin C, also known as ascorbic acid and L-ascorbic acid, is a vitamin found in food and used as a dietary supplement. The disease scurvy is prevented and treated with vitamin C-containing foods or dietary supplements.Vitamin C (also known as ascorbic acid) is abundant in vegetables and fruits. A water-soluble vitamin and powerful antioxidant, it helps the body form and maintain connective tissue, including bones, blood vessels, and skin.Vitamin C helps to repair and regenerate tissues, protect against heart disease, aid in the absorption of iron, prevent scurvy, and decrease total and LDL (“bad”) cholesterol and triglycerides. Research indicates that vitamin C may help protect against a variety of cancers by combating free radicals, and helping neutralize the effects of nitrites (preservatives found in some packaged foods that may raise the risk of certain forms of cancer). Supplemental vitamin C may also lessen the duration and symptoms of a common cold, help delay or prevent cataracts, and support healthy immune function. Below I have included three videos which go into great detail about vitamin C each from a slightly different perspective but certainly three expert presentations from Dr. Peter Osborne, Dr. Rhonda Patrick and Dr. Chris Masterjohn.
Deficiency symptoms include fatigue, muscle weakness, joint and muscle aches, bleeding gums, and leg rashes. Prolonged deficiency can cause scurvy, a rare but potentially severe illness.
According to the National Institutes of Health (NIH), the recommended vitamin C daily allowance (RDA) is:
Men, 90 mg per day
Women, 75 mg per day
Pregnant women, 85 mg per day
Breastfeeding women, 120 mg per day.
Infants 0-6 months old, 40 mg per day
Infants 7-12 months old, 50 mg per day.
Toddlers 1-3 years old, 15 mg per day
Children 4-8 years old, 25 mg per day
children 9-13 years old, 45 mg per day
Male teens 14-18 years old, 75 mg per day
Female teens 14-18 years old, 65 mg per day
Sources of Vitamin C
Vitamin C is easy to get through foods, as many fruits and vegetables contain vitamin C. Good sources include: apples, asparagus, berries, broccoli, cabbage, melon (cantaloupe, honeydew, watermelon), cauliflower, citrus fruits (lemons, limes, oranges), kiwi, fortified foods (breads, grains, cereal), dark leafy greens (kale, spinach), peppers (especially red bell peppers, which have among the highest per-serving vitamin C content), potatoes, and tomatoes.
100g of the following foods showing the amount of vitamin C from the top 24 vegan sources
Dried Coriander – 566.7mg (630% DV)
Hot Green Chili Peppers – 242.5mg (269% DV)
Guavas – 228.3mg (254% DV)
Dried Jujube – 217.6mg (242% DV)
Sweet Yellow Peppers – 183.5mg (204% DV)
Dried Litchis – 183mg (203% DV)
European Black Currants – 181mg (201% DV)
Cooked Red Bell Peppers – 171mg (190% DV)
Thyme (Fresh) – 160.1mg (178% DV)
Red Chili Peppers – 143.7mg (160% DV)
Parsley – 133mg (148% DV)
Mustard Spinach – 130mg (144% DV)
Scotch Kale – 130mg (144% DV)
Sweet Red Bell Peppers – 127.7mg (142% DV)
Dried Parsley – 125mg (139% DV)
Kale – 120mg (133% DV)
Jalapeno Peppers – 118.6mg (132% DV)
Vinespinach – 102mg (113% DV)
Hungarian Peppers – 92.9mg (103% DV)
Kiwifruit – 92.7mg (103% DV)
Broccoli – 89.2mg (99% DV)
Green Cauliflower – 88.1mg (98% DV)
Dill – 85mg (94% DV)
Brussels Sprouts (Raw) – 85mg (94% DV)
Vitamin C
In 1970, double Nobel Prize laureate Dr. Linus Pauling published Vitamin C and the Common Cold, in which he posited that consuming large amounts of vitamin C could reduce the duration and severity of the common cold. The book effectively put vitamin C on the nutritional map, establishing it as a cure-all in the collective minds of the lay public. Nearly a decade later, Pauling published clinical data suggesting that high dose intravenous administration of vitamin C showed promise as a supportive treatment for cancer as well as a strategy to mitigate the side effects of chemotherapy. Pauling’s work was heavily criticized in the scientific community, however, due to a lack of proper controls and standardization. Since then, countless studies have tested Pauling’s theories about vitamin C, colds, and cancer (and many others), and a substantial body of evidence has emerged, identifying critical roles for vitamin C in immune function, cardiovascular and respiratory health, cognitive development and preservation, and many other aspects of human health.
Bioavailability of vitamin C
The absorption, distribution, metabolism, and excretion of vitamin C are complex and differ considerably from other low molecular weight compounds. Consequently, the bioavailability of vitamin C is both frequency- and dose-dependent. But the form of vitamin C impacts bioavailability, too. For example, oral vitamin C is absorbed in the small intestine via specialized transporters that are subject to saturation, but intravenous vitamin C bypasses the gut, achieving blood and tissue concentrations that are markedly higher than those achieved with the oral form. In fact, in healthy adults, intravenous administration of vitamin C can reach blood concentrations that are 30 to 70 times higher than equivalent oral doses.
Vitamin C as antioxidant
Much of vitamin C’s effectiveness arises from its capacity to serve as an antioxidant – readily donating electrons to oxidized molecules, thereby quenching reactive oxygen species and preventing oxidative stress. This is perhaps best demonstrated in neutrophils, a type of immune cell that actively participates in eliminating pathogens from the body. Neutrophils generate large quantities of reactive oxygen species, putting them at risk for oxidative stress-induced DNA damage. Vitamin C is highly concentrated in neutrophils, however, with concentrations averaging roughly 50 times higher than plasma concentrations. In a strange paradox, the high levels of vitamin C present in neutrophils protect them from reactive oxygen species-induced DNA damage while simultaneously promoting the molecules’ production.
Vitamin C as anti-infectious agent
After more than 50 years of research, the evidence supporting vitamin C’s effectiveness against the common cold is still variable, likely due to widespread inconsistencies in study methodologies that span an extensive range of protocols. Despite these inadequacies, meta-analyses broadly demonstrate a protective effect, particularly with higher doses. However, even under the most rigorous testing, vitamin C likely shortens or lessens the duration of the common cold by hours, not days. Some populations, such as children and endurance athletes – who tend to have more colds than the average person – seem to benefit more from vitamin C’s effects, especially when taken prophylactically.
Other data suggest that vitamin C reduces the risk of a litany of viral infections, from chickenpox to shingles to HIV. Perhaps more compelling are the data supporting vitamin C’s use in the treatment of sepsis, a life-threatening condition that can arise when the body responds to a bacterial or viral infection. Sepsis ravages the body, provoking severe injury to multiple tissues and organs, often resulting in death. Recent evidence indicates that SARS-CoV-2, the novel coronavirus that causes COVID-19, induces sepsis. Interestingly, people who have sepsis often exhibit low vitamin C levels, which might be predictive of increased risk for organ failure. Vitamin C might be an effective treatment for sepsis because it modulates the proinflammatory state associated with sepsis and preserves organ function.
The beneficial properties of vitamin C extend beyond its ability to support immune function support and prevention of colds, conferring a wide range of salubrious effects on multiple organ systems, including respiratory, cardiovascular, neurological, and reproductive systems.
An Excellent Article On Vitamin C by Dr. Rhonda Patrick