Preventing the Common Cold With a Vitamin C Supplement: A Double-Blind, Placebo- Controlled Survey

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1 Advances In Therapy Volume 19 No. 3 May/June 2002 Advances In Natural Therapy With a Vitamin C Supplement: A Double-Blind, Placebo- Controlled Survey Michael Van Straten Peter Josling, B.Sc. Hons. Herbal Health Centre Battle, East Sussex United Kingdom ABSTRACT One hundred sixty-eight volunteers were randomized to receive a placebo or a vitamin C supplement, two tablets daily, over a 60-day period between November and February. They used a five-point scale to assess their health and recorded any common cold infections and symptoms in a daily diary. Compared with 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 significantly shorter 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 faster if infected. Few side effects occurred with the active treatment, and volunteers reported greatly increased satisfaction with the study supplement compared with any previous form of vitamin C. This well-tolerated vitamin C supplement may prevent the common cold and shorten the duration of symptoms. Volunteers were generally impressed by the protection afforded them during the winter months and the general acceptability of the study medication. Keywords: common cold; vitamin C INTRODUCTION The common cold is the world s most widespread viral infection, with most people suffering approximately two to five colds per year. 1 Over 200 different viruses cause infection and cold symptoms; the most common, rhinoviruses, account for 30% to 40% of adult colds. Re-infection is prevalent because of the many varieties of infectious viruses Health Communications Inc. Transmission and reproduction of this material in whole or part without prior written approval are prohibited Address reprint requests to Mr. Peter Josling Herbal Health Centre Battle, East Sussex, United Kingdom 151

2 Consumers are often encouraged to take large doses of vitamin C supplements to prevent or relieve symptoms of the common cold, 2-4 although researchers disagree on the efficacy of taking any vitamin C preparation for either purpose. In fact, the most recent research suggests that vitamin C has no particular benefit over a placebo, 5,6 particularly if the window of opportunity is missed. The purpose of this double-blind, placebo-controlled survey was to ascertain whether a specific form of vitamin C could offer a degree of prevention when used throughout 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 allows cells to efficiently absorb and retain high levels of the vitamin. It is postulated that rapid cellular absorption and delayed renal excretion of ascorbic acid maximize its cellular concentration to provide high levels of biochemical activity 7 and strengthen the immune system, rendering it less likely to suffer during viral challenge. A cure for the common cold would substantially reduce the number of work days lost 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, United States, and Europe vary widely by type and recommended dietary allowance. Increasing evidence has shown that Ester-C ascorbate may have significant beneficial properties, because the ascorbate is readily used by white blood cells, potentiating immune cell function. 8 METHODS One hundred sixty-eight participants were recruited through an editorial in the consumer media. A diary was designed in which volunteers recorded general wellbeing for 60 days on a five-point scale (5 = well, no problems; 4 = quite well with occasional 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 = full cold symptoms [headache, sneezing, runny nose, sore throat, cough, tiredness]) and assessed the number and severity of coughs and colds experienced during the trial period. This scale has been used previously to assess the degree and severity of cold symptoms. 9 If a cold occurred, volunteers noted the number and variety of symptoms, the day recovery began, and the day they felt completely better. Volunteers were separated into two groups of 84 participants (Table 1). A simple random number generator assigned volunteers to the active or placebo group, and they were instructed to take two tablets (Ester-C ascorbate 500 mg or a matched placebo) every day with their main meal, according to the manufacturer's recommendation. General dietary habits were determined before the study, and volunteers were told not to make any dramatic changes. Individuals who had already received an influenza inoculation were excluded from the statistical analysis, as were those who were currently taking a vitamin C product. Randomization codes were kept secure and were not broken until all the survey data had been returned. The Herbal Health Centre contacted volunteers at random every 2 weeks to ensure that tablets were being consumed correctly and that any infection was recorded appropriately. A subset of 104 volunteers completed a questionnaire designed to ascertain their personal circumstances and provide a subjective 152 M. Van Straten, P. Josling

3 evaluation of the quality and acceptability of the treatment they received (Appendix). The remaining 64 participants were instructed to record comments and observations in the diary. Table 1. Demographics Treatment Placebo Characteristic (n=84) (n=84) Men Women Mean age, y Previous use of vitamin C supplements, no This double-blind survey used a matched placebo control that looked and tasted exactly the same as the active material. Both compounds were supplied in plain white 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 and February. A tablet count at the end of the survey indicated compliance. Data Analysis After diaries were returned, the number of colds experienced by volunteers was counted. 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 all recorded colds. The number of days on which infected volunteers recorded a score of 1 was further analyzed to identify any difference in duration of full cold symptoms. The number of coughs, colds, and other symptoms was noted, as was the overall incidence of adverse events, which included heartburn, indigestion, and stomach upsets. Volunteers also recorded other concerns acceptability of taking tablets, side effects such as odor, or other reasons that might warrant discontinuation of treatment and telephoned the Herbal Health Centre for further advice. Volunteers compared their subjective experience during this winter period with previous years and were asked whether they would continue taking the compound and recommend it to a friend (see Appendix for results). Statistical Analysis The average symptom length in days and the total number of colds per group were subjected to calculations of standard deviation, sample variance, and standard error of the difference of the means. Data were analyzed by means of a Student s t test to gain a probability coefficient allowing for the calculated number of degrees of freedom. Advances In Therapy Volume 19 No. 3, May/June

4 RESULTS Two participants withdrew from the study for personal reasons, but at the end of the 60-day period, 37 colds were recorded in the active group and 50 colds in the placebo group (P<.05 in favor of the supplement as a cold preventative). The placebo group recorded an average of 3.1 days with a symptom score of 1 (178 days of infection/50 colds), ie, fully infected with multiple symptoms, compared with only 1.8 days (85/37) in the active group (P<.03) (Table 2). Table 2. Total Number of Colds and Prevalence of Full Cold Symptoms Characteristic Treatment Placebo Average duration of symptoms, d Sample variance Standard deviation Standard error, difference of means Student s t distribution 3.6 Degrees of freedom 156 Probability P<.03 Total number of colds Sample variance Student s t distribution.375 Probability P<.05 During the study, 16 volunteers taking the placebo became reinfected (experienced more than one full-blown cold); only 2 volunteers taking the active supplement had a reinfection. The overall incidence of side effects was low. Indigestion was most common in the placebo group at 10%, compared with 4% in the active group. Respective incidences of heartburn were 4% and 7%. These percentages are far lower than previously reported by volunteers who had taken ordinary ascorbic acid supplements in the past, indicating greater tolerability of the study preparation (see Appendix). The subset of 104 volunteers reported a 77% reduction in the number of coughs compared with previous winters. Moreover, 85% of respondents in the active group would continue taking the compound, and 81% would recommend it to friends and family. Perhaps not surprisingly, 64% of the active group felt better or much better during the trial. 154 M. Van Straten, P. Josling

5 DISCUSSION This study is the first to use a double-blind, placebo-controlled design to investigate prevention of a viral disease with a vitamin C supplement. The results favor the supplement as a preventive measure, demonstrating accelerated relief, reduction in the severity of troublesome symptoms such as sneezing, cough, and runny nose, recovery to full fitness, and a small but significant reduction in the total number of colds. Of particular note is that volunteers in the active group who contracted a cold showed a reduction in the time to begin recovery and to relieve symptoms. A difference of just over 1 day is of the same order of magnitude that could be reasonably expected from pharmaceutical or over-the-counter medications. This study suggests that the vitamin C supplement evaluated may offer significant benefits over ordinary ascorbic acid or vitamin C. Although claims of a cure for the common cold are unwarranted, the results support prevention of infection as well as a faster recovery with Ester-C ascorbate compared with placebo. Large numbers of individuals are at particular risk during the winter, and the incidence of summer colds continues to increase. Daily use of Ester-C ascorbate throughout the year may substantially reduce the number of infectious incidents suffered by the working population and lead to potential savings in terms of decreased sick days. Ester-C ascorbate warrants further investigation to determine the precise nature and method of its antiviral activity. ACKNOWLEDGMENTS We thank all the volunteers and are grateful to Debbie Murphy for her excellent administrative assistance. The Ester-C and matched placebo tablets were provided by the Inter-Cal Corporation, Prescott, Arizona, USA. REFERENCES 1. Eccles R. Common Cold Centre, Cardiff, UK. Available at: cold/home.html. 2. Hemila H. Vitamin C intake and susceptibility to the common cold. Br J Nutr. 1997;77: Hemila H. Vitamin C and common cold incidence: a review of studies with subjects under heavy physical stress. Int J Sports Med. 1996;17: Hemila H. Vitamin C and the common cold. Br J Nutr. 1992;67: Hemila H, Herman ZS. Vitamin C and the common cold: a retrospective analysis of Chalmers review. J Am Coll Nutr. 1995;14: Audera C, Patulny R, Sander B, Douglas R. Mega-dose vitamin C in treatment of the common cold: a randomised controlled trial. Med J Aust. 2001;175: Bush MJ, Verlangieri AJ. An acute study on the relative GI absorption of a novel form of calcium ascorbate. Res Commun Chem Pathol Pharmacol. 1987;57: Fay MJ, Verlangieri AJ. Stimulatory action of calcium threonate on ascorbic acid uptake by a human T-lymphoma cell line. Life Sci. 1994;49: Josling PD. Preventing the common cold with a garlic supplement: a double-blind placebocontrolled survey. Adv Ther. 2001;18: Advances In Therapy Volume 19 No. 3, May/June

6 Appendix A subset of 104 volunteers answered a series of questions designed to provide personal details, a subjective assessment of the relative merits of treatment, and perceived improvement during survey period. A pretrial questionnaire was used. After the survey was completed and the volunteers had been unblinded, a posttrial assessment was undertaken. At Registration Average age of participants, y Are you receiving medical treatment or taking any long-term medication at the moment? (%) Yes No Pretrial Questionnaire Which best describes your usual state of health? (%) I am very healthy I am reasonably healthy but could be better Sometimes healthy, sometimes not 4 9 I am unwell, ill, in poor health 2 4 Do you smoke cigarettes? (%) No Yes On a normal day, how many cigarettes do you smoke? (%) Fewer than Continued 156 M. Van Straten, P. Josling

7 Pretrial Questionnaire (cont d) Do you drink alcohol? (%) No Yes Average alcohol consumption per week, units Average portions of fruit and vegetables eaten per day Average number of infections in normal year Of these episodes, how many times do you catch A cold A cough Flu How long do your colds normally last? Fewer than 3 days 4 6 Up to 5 days More than 5 days When you catch a cold, do you normally expect to get (%) Headaches Sore throat Blocked sinuses A chest infection Do the secondary effects of colds keep you out of action, away from college, or off work? (%) No Yes If yes, for approximately how many days (average) after each infection? Do you suffer from asthma or any chronic obstructive airways disease that makes it more serious if you catch a cold? (%) No Yes 0 2 Continued Advances In Therapy Volume 19 No. 3, May/June

8 Pretrial Questionnaire (cont d) Have you ever taken a vitamin C supplement to prevent winter infections? (%) No Yes If yes, have you ever had problems with heartburn, acid indigestion, or other gastric upsets? (%) No Yes End-of-Survey Questionnaire Have you taken your tablets every day for the past 60 days? (%) Yes Almost No 0 2 While taking the tablets, did you suffer any problems with (%) Heartburn 8 4 Indigestion 4 11 Stomach upset 0 0 During the past 60 days, how many episodes of coughs, colds, or flu have you had? Coughs Colds During the past 60 days, have you caught any other infection? (%) No Yes Continued 158 M. Van Straten, P. Josling

9 End-of-Survey Questionnaire (cont d) How have you felt during the past 60 days compared with previous winters? (%) Much better Better The same Worse 0 0 Based on your experience in the past 60 days, would you continue taking a supplement for the rest of the winter? (%) Yes No Based on your experience, would you recommend a winter course of a vitamin C supplement to your friends and family? (%) Yes No Advances In Therapy Volume 19 No. 3, May/June