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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    Vitamin C and exercise-induced bronchoconstriction

    Ascorbic acid (vitamin C) supplementation protected against exercise-induced airway narrowing in this small group of people with asthma.

    The study design makes this research noteworthy.

    First, the details.

    • 8 people with asthma and documented exercise-induced bronchospasm (EIB) were studied.
    • They continued their usual diet.
    • Each person received each treatment in this crossover design: 2 weeks of ascorbic acid supplementation (1500 mg/day) or placebo in random order.

    And, the results .

    • Ascorbic acid significantly reduced the maximum fall in post-exercise FEV1.
    • FEV1 (forced expiratory volume at 1 second) is a measure of the maximum volume of air breathed out in 1 second.
    • Asthma symptoms scores significantly improved.
    • Other measures of airway inflammation and the allergic response also significantly improved with the ascorbic acid compared to the placebo and usual diet.

    It’s a small study. But the fact that each person received each treatment advances our understanding of vitamin C and lung reactivity to exercise in asthmatic patients.

    These results are supported by earlier research in this field.


    • In 12 asthmatic patients, pretreatment with ascorbic acid 500 mg led to a significant attenuation in bronchospasm 5 minutes after exercise compared to placebo.
    • The results suggested a mild antibronchospastic action of ascorbic acid in subjects with EIB.


    • In 10 asthmatic patients who had stopped taking their asthma medicine, administration of ascorbic acid 2 grams showed no effect on lung function.
    • However, 9 patients showed a protective effect on exercise-induced hyper-reactive airways
    • And 4 of 5 taking ascorbic acid 500 mg/day for 2 more weeks maintained the protective effect.

    The bottom line?
    Everybody says more research is needed. But as it now stands, taking 500 to 1500 mg of vitamin C each day might help protect against exercise-induced airway narrowing in people with asthma.

    7/4/07 13:00 JR

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