Having just gotten over an upper respiratory infection (URI), this interview with Naama Constantini, MD, DFM, FACSM, Dip. Sport Med. (CASM), by Kirk Hamilton came at a great time. Dr. Constantini discusses the role that the antioxidant vitamin C plays in swimmers with URIs.
Kirk Hamilton: Can you please share with us your educational background and current position?
Naama Constantini: I am a physician and a family and sport medicine specialist. I am the director of the “Hadassah Optimal” Sports Medicine Center, Orthopedic Department, Hadassah-Hebrew University Medical Center in Jerusalem, Israel. I was the chair of the Medical Committee of the Israeli Olympic Committee for
over 10 years and currently the physician of the Israeli Swimming Association. In addition, I am an active Master competitive swimmer, and a former swimming coach.
KH: What got you interested in studying the role of vitamin C in upper respiratory infections (URI) in adolescent swimmers?
NC: A URI at the wrong time can prejudice the career of a professional athlete. URIs are more prevalent among athletes at the elite level, especially swimmers. Many nutritional supplements have been tested in attempts to reduce the rate of URIs and/or their severity – nearly all with disappointing results. In a recent Cochrane review, vitamin C supplementation has been shown beneficial in decreasing the rate of common colds in active populations and in children. Therefore, it could assist young swimmers, and this has not been examined yet.
KH: What is the biochemistry of vitamin C that might reduce the incidence of URIs?
NC: Vitamin C is a potent antioxidant and reducing substance, which has several activities in nature. In humans, it is also related to several components of the immune system, such as improving leukocyte and lymphocyte functions. These cells may act against the invading virus.
KH: Where did you come up with a daily dose of 1000 mg per day of vitamin C? How was it taken? With meals or away from meals? In a single dose or divided dose?
NC: One to two grams per day was the common dosage of vitamin C in similar trials in children. The vitamin was given in the form of a 500 mg pill, twice a day, away from meals as possible.
KH: Were blood levels of vitamin C or other biochemical markers taken before, during or after the intervention?
NC: Bloods were drawn for vitamin C levels, but due to technical difficulties, these data were eventually not analyzed.
KH: Can you tell us about your study and the basic results?
NC: This study was a randomized, double-blind, placebo-controlled trial which lasted over three winter months, among 39 competitive young swimmers (mean age 13.8±1.6 years) in Jerusalem, Israel. URI symptoms were self-recorded daily by the participants. Our results were that vitamin C had no effect on the
incidence of URIs. It shortened the duration of infections in male swimmers by 47%, with no effect in females. It also decreased the severity of URIs in males only.
KH: Were there any side effects with the vitamin C therapy? How was the patient compliance?
NC: No side effects were identified, and no formal assessment on compliance was made.
KH: Who is a candidate for vitamin C therapy? All subjects at risk for URIs? Only swimmers?
NC: From our study and previous work during the past 30-40 years, it appears that vitamin C does have some protection against URIs in this age group. In children from the general population, its effect is too small from the clinical aspect to warrant daily use. In male swimmers, daily use through the winter halved the duration of URI episodes from an average of 10 days to an average of 5. Young male swimmers seem to be potential candidates for such therapy – but each should individually decide if taking daily pills is worth the anticipated, average clinical effect.
KH: Many clinicians who use vitamin C to prevent or treat viral illnesses use much higher doses than 1000 mg per day? Any possibility that higher doses might have greater benefit?
NC: A recent 2010 Cochrane review summarized the data accumulated from over 40 years of research on vitamin C and such viral illnesses. The authors concluded that such supplementation, even in mega-doses of 3, 4 or even 8 grams, does not have any consistent and significant clinical effect in adults.
KH: How can the public or health professionals use this information?
NC: Our findings are encouraging, that a possible treatment option for URIs in young swimmers exists. Yet the results of our trial should be replicated in additional populations, in order to draw a wider picture.
KH: Do you have any further comments on this very interesting subject?
Interview from Vitasearch.