The C.A.M. Report
Complementary and Alternative Medicine: Fair, Balanced, and to the Point
  • About this web log

    This blog ran from 2006 to 2016 and was intended as an objective and dispassionate source of information on the latest CAM research. Since my background is in pharmacy and allopathic medicine, I view all CAM as advancing through the development pipeline to eventually become integrated into mainstream medical practice. Some will succeed while others fail. But all are treated fairly here.

  • About the author

    John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.

  • Common sense considerations

    The material on this weblog is for informational purposes. It is not medical advice or counsel. Be smart, consult your health professional before using CAM.

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    In support of a higher RDA for vitamin C

    Researchers from Université de Lille 2 and Université de La Réunion in France have written a detailed and extensively referenced review of the current state of vitamin C supplementation.

    Here are the highlights of their case for increasing the recommended daily allowance (RDA) of vitamin C supplementation to 1 gram, accompanied by a diet rich in fruits and vegetables.

    The article is more than 7000 words. So, what follows is a top line summary.

    Functions of vitamin C

    • Vitamin C is required for maintenance of normal connective tissue and wound healing.
    • It’s also required for bone remodeling and other metabolic reactions, among other needs.

    Recommended dietary allowance of vitamin C

    • People vary widely in their vitamin C requirements.
    • The current RDA for vitamin C is based on twice the amount needed to prevent scurvy and the threshold to spill vitamin C into urinary excretion.
    • Many reviewers suggest that intake of vitamin C much higher than the RDA may reduce the risk or risk factors for chronic diseases such as heart disease and certain types of cancer.
    • But there’s no justification for routine megadose vitamin C, 1–3 grams/day, in the normal population.

    Bodily needs in vitamin C

    • Needs vary among different people and under different conditions.
    • For example, the elderly have reduced concentrations of vitamin C in blood and white blood cells.
    • Vitamin C supplementation (500 mg/day for 1 month) enhanced the immune response of T lymphocytes .
    • In healthy people with higher concentrations of vitamin C (1 grams/day), white blood cells are more active and could speed their respond to infection or inflammation.

    Vitamin C consumption higher than the RDA

    • Higher doses of vitamin C (2500 mg daily) taken by mouth result in higher vitamin C blood levels.
    • High levels of vitamin C protect against damage to blood vessels and reduce mortality rates in the elderly.
    • Taking hourly doses of 1000 mg of vitamin C for the first 6 hours after the onset of cold symptoms and 3 times daily thereafter decreased flu and cold symptoms by 85% vs a control group.
      • Although other studies show conflicting results.
    • Based on the literature, the authors suggest a minimum vitamin C consumption of 1 gram daily in healthy people in order to complete a prevention program for many diseases.

    Safety of vitamin C supplementation

    • Gastrointestinal distress is the most common side effect of high vitamin C intake.
    • When it occurs, the vitamin C dose is usually at least 2 grams/day.
    • Symptoms usually disappear in 2 weeks.

    The bottom line?
    The authors state that there’s evidence that vitamin C prevents and treats a broad range of diseases. Yet, the current RDA for vitamin C does not cover the need for vitamin C in daily bodily functions.

    “Consequently, even if vitamin C requirements vary greatly among individuals, it is suggested that vitamin C supplementation is not only totally safe but also necessary to achieve optimal health. Therefore, in agreement with the current literature, we advise healthy people to consume 5 servings of fruits and vegetables daily, added to 1 gram of vitamin C supplementation divided in 2 or 3 doses during the day, in order to ensure an optimal allowance in vitamin C to achieve optimal health.”

    12/3/08 2:30 JR

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