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Vitamin C

Episodes

Posted on September 7th 2023 (over 1 year)

Dr. Rhonda Patrick explores growth hormone secretagogues, spermidine's longevity role, methylene blue, whey protein, and solutions for scar tissue in a Q&A.

Posted on April 30th 2022 (about 3 years)

Dr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.

Posted on April 3rd 2022 (about 3 years)

In this clip, Dr. Rhonda Patrick discusses the safety and side effects of intravenous vitamin C and describes the evidence supporting its use in treating COVID-19.

Topic Pages

  • Multivitamins

    Multivitamin and multimineral supplements are used by nearly one-third of adults to improve health and mitigate disease risk.

News & Publications

  • Supplemental vitamin C and arginine reduce symptoms associated with long COVID, a new study shows. People who took the combined supplements experienced less fatigue and performed better during exercise.

    Researchers gave people with long COVID either a combination of liposomal vitamin C and arginine or a placebo for four weeks. They measured their walking speed, strength, and endothelial function before and after the intervention.

    They found that those who took the vitamin C/arginine combination improved on measures of speed, strength, and endothelial function compared to those who took the placebo. They were also less likely to report experiencing fatigue.

    Vitamin C is an essential nutrient that exerts robust antioxidant properties. Evidence suggests that liposomal formulations of vitamin C are more bioavailable than conventional forms. Learn more about vitamin C in our overview article. Arginine is an amino acid that plays roles in vasodilation. Evidence suggests that arginine metabolism is altered in the setting of COVID-19.

  • Re-analysis of landmark vitamin C trial data reveals current recommendations for intake may be too low for optimal health.

    During World War II, researchers in England conducted an experiment to determine the level at which vitamin C depletion causes scurvy, a potentially life-threatening collagen-related disorder. A re-analysis of these findings calls into question current recommendations for vitamin C intake.

    The study involved 20 healthy men who had been fed a diet providing 60 to 70 milligrams of vitamin C daily for about one month. The researchers randomly assigned the men to receive zero, 10, or 70 milligrams of vitamin C daily. Because vitamin C plays such an important role in wound healing, the researchers subjected the participants to experimental wounds and then assessed the scar strength to gauge the effects of depletion. They concluded that a dose of 10 milligrams of vitamin C daily was sufficient for optimal scar strength. The study’s findings formed the basis of public health recommendations that soon followed and, in some countries, are still observed today.

    However, the authors of the present-day article posited that the data analysis from the World War II-era study was flawed. They subjected the data to a new analysis, which revealed that the daily intake of vitamin C for providing adequate scar strength is 95 milligrams – twice the amount recommended by the World Health Organization and the National Health Service of the United Kingdom.

    These findings suggest that the landmark study on which some public health recommendations base their recommendations for vitamin C intake grossly underestimated the dose required for wound healing and optimal health. Learn more about vitamin C in our overview article.

  • Exercise-induced bronchoconstriction – a narrowing of the airways in response to exercise – occurs in as much as 10 percent of the general population and up to 50 percent in some fields of competitive athletics. Findings from a meta-analysis suggest that vitamin C might reduce the incidence of exercise-induced bronchoconstriction.

    Previous research demonstrated that vitamin C can triple respiratory tissue levels within an hour or two of a single oral dose of 1 or 2 grams. This local increase in vitamin C concentration appears to protect against acute increases in airway oxidative stress. In addition, vitamin C inhibits the production of prostaglandins and leukotrienes, biological compounds that participate in the pathogenesis of exercise-induced bronchoconstriction.

    In addition, vitamin C halved the incidence of the common cold among people experiencing heavy short-term physical stress – an indication that vitamin C might also have other effects on people experiencing heavy physical exertion.

    The authors of the current conducted analyses of nine studies that investigated varied aspects of the effects of vitamin C on exercise-induced bronchoconstriction. Three placebo-controlled studies analyzed the relative exercise-induced decline in forced expiratory volume, or FEV1, (a measure of respiratory capacity) with or without a vitamin C. They found that doses ranging between 0.5 and 2 grams of vitamin C reduced FEV1 decline by half. Similarly, five studies investigated the effects of vitamin C supplementation on respiratory symptoms after short-term heavy physical work and found that incidence was halved. One study investigated the duration of respiratory symptoms in young male swimmers and also found that incidence was halved.

    The authors noted that a variety of factors might influence whether and to what degree vitamin C affects respiratory function during exercise, including the type of activity and the conditions under which it is performed, among others.

  • From the article:

    Miller and his colleagues reviewed and analyzed data from 29 randomized, controlled, previously published clinical trials that reported systolic and/or diastolic blood pressure values and also compared vitamin C intake to a placebo. What they found is that taking an average of 500 milligrams of vitamin C daily – about five times the recommended daily requirement – reduced blood pressure by 3.84 millimeters of mercury in the short term. Among those diagnosed with hypertension, the drop was nearly 5 millimeters of mercury.

    A comparison to common pharmacological treatment:

    By comparison, Miller says, patients who take blood pressure medication such as ACE inhibitors or diuretics (so-called “water pills”) can expect a roughly 10 millimeter of mercury reduction in blood pressure.

  • The bulk of scientific research on the effectiveness of vitamin C in fighting infection has centered on reducing the symptoms and duration of the common cold. Much of the studies have used doses of approximately 1 gram per day. Findings from a 2017 study suggest that larger doses might reduce a cold’s duration.

    Although most adults typically have only one or two colds per year, cold symptoms are the reason for many lost days of work or school. Some evidence suggests that the financial costs associated with having a cold are similar to those associated with having high blood pressure or a stroke.

    The author of the study reviewed the findings of two randomized trials focused on the effectiveness of vitamin C in reducing cold symptom duration. One of the trials had four treatment groups: one group that took a placebo, two groups that took 3 grams per day, and one group that took 6 grams per day. The 6-gram dose reduced cold symptom duration by about 17 percent – roughly twice as much as that observed with only 3 grams. The placebo had no effect on symptom duration. The other trial had three treatment groups: one that took 4 grams per day, one that took 8 grams per day, and one that took a placebo. Taking 8 grams per day reduced symptom duration by 21 percent, compared to the placebo group.

    These findings suggest that large doses of oral vitamin C might reduce the duration of symptoms associated with the common cold, but self-dosing should commence as soon as cold symptoms appear for the greatest benefit.