Preventing the Common ColdWith a Vitamin C Supplement:A Double-Blind, Placebo-Controlled SurveyMichael Van StratenPeter Josling, B.Sc. Hons.Herbal Health CentreBattle, East SussexUnited KingdomABSTRACTOne hundred sixty-eight volunteers were randomized to receive a placebo or a vitamin C supplement, two tablets daily, over a 60-day period betweenNovember and February. They used a five-point scale to assess their health andrecorded any common cold infections and symptoms in a daily diary. Comparedwith the placebo group, the active-treatment group had significantly fewer colds(37 vs 50, P<.05), fewer days challenged virally (85 vs 178), and a significantlyshorter duration of severe symptoms (1.8 vs 3.1 days, P<.03). Consequently, volunteers in the active group were less likely to get a cold and recovered fasterif infected. Few side effects occurred with the active treatment, and volunteersreported greatly increased satisfaction with the study supplement compared withany previous form of vitamin C. This well-tolerated vitamin C supplement mayprevent the common cold and shorten the duration of symptoms. Volunteers weregenerally impressed by the protection afforded them during the winter monthsand the general acceptability of the study medication.Keywords: common cold; vitamin CINTRODUCTIONThe common cold is the world’s most widespread viral infection, withmost people suffering approximately two to five colds per year.1Over 200different viruses cause infection and cold symptoms; the most common,rhinoviruses, account for 30% to 40% of adult colds. Re-infection is preva-lent because of the many varieties of infectious viruses.1151AdvancesIn Therapy®Volume 19 No. 3May/June 2002Address reprint requests toMr. Peter JoslingHerbal Health CentreBattle, East Sussex, United Kingdom©2002 Health Communications Inc.Transmission and reproduction of this material in wholeor part without prior written approval are prohibited.0673Advances In Natural Therapy™Consumers are often encouraged to take large doses of vitamin C supplements toprevent or relieve symptoms of the common cold,2-4although researchers disagreeon the efficacy of taking any vitamin C preparation for either purpose. In fact, themost recent research suggests that vitamin C has no particular benefit over a place-bo,5,6particularly if the “window of opportunity” is missed. The purpose of this double-blind, placebo-controlled survey was to ascertainwhether a specific form of vitamin C could offer a degree of prevention when usedthroughout the winter months rather than when used once an infection had begun.The active preparation was Ester-C ascorbate, a natural form of vitamin C that allowscells to efficiently absorb and retain high levels of the vitamin. It is postulated thatrapid cellular absorption and delayed renal excretion of ascorbic acid maximize its cel-lular concentration to provide high levels of biochemical activity7and strengthen theimmune system, rendering it less likely to suffer during viral challenge. A “cure” for the common cold would substantially reduce the number of work dayslost each year as a result of symptoms of infection including tiredness, headaches,runny nose, sneezing, coughing, watery eyes, and impaired concentration.The many vitamin C supplements marketed in the United Kingdom, UnitedStates, and Europe vary widely by type and recommended dietary allowance.Increasing evidence has shown that Ester-C ascorbate may have significant benefi-cial properties, because the ascorbate is readily used by white blood cells, potentiat-ing immune cell function.8METHODSOne hundred sixty-eight participants were recruited through an editorial in theconsumer media. A diary was designed in which volunteers recorded general well-being for 60 days on a five-point scale (5 = well, no problems; 4 = quite well withoccasional sneeze, not disruptive to normal routine; 3 = can feel a cold coming on,some minor symptoms; 2 = feeling low and beginning to exhibit symptoms; 1 = fullcold symptoms [headache, sneezing, runny nose, sore throat, cough, tiredness]) andassessed the number and severity of coughs and colds experienced during the trialperiod. This scale has been used previously to assess the degree and severity of coldsymptoms.9If a cold occurred, volunteers noted the number and variety of symp-toms, the day recovery began, and the day they felt completely better. Volunteers were separated into two groups of 84 participants (Table 1). A simplerandom number generator assigned volunteers to the active or placebo group, andthey were instructed to take two tablets (Ester-C ascorbate 500 mg or a matchedplacebo) every day with their main meal, according to the manufacturer's recom-mendation. General dietary habits were determined before the study, and volun-teers were told not to make any dramatic changes. Individuals who had alreadyreceived an influenza inoculation were excluded from the statistical analysis, aswere those who were currently taking a vitamin C product.Randomization codes were kept secure and were not broken until all the surveydata had been returned. The Herbal Health Centre contacted volunteers at randomevery 2 weeks to ensure that tablets were being consumed correctly and that any infection was recorded appropriately. A subset of 104 volunteers completed a ques-tionnaire designed to ascertain their personal circumstances and provide a subjective152M. Van Straten, P. JoslingPreventing the Common Coldevaluation of the quality and acceptability of the treatment they received (Appendix).The remaining 64 participants were instructed to record comments and observationsin the diary. This double-blind survey used a matched placebo control that looked and tastedexactly the same as the active material. Both compounds were supplied in plainwhite bottles, and volunteers were told to take two 500-mg tablets every day at the same time, preferably with food, during a 60-day period between November andFebruary. A tablet count at the end of the survey indicated compliance. Data AnalysisAfter diaries were returned, the number of colds experienced by volunteers wascounted. A cold was defined as a score of 3 that proceeded to 2 or 1, with symptoms.The duration of symptoms was the number of days with a recorded score of 2 or 1,leading to an average recovery time that ended with a score of 4 or 5 taken across allrecorded colds. The number of days on which infected volunteers recorded a score of1 was further analyzed to identify