Who and how many people are taking herbal supplements? A survey of 21,923 adults.

BACKGROUND: There is little information on the number and characteristics of adults taking herbal supplements and the relationship of this with other health and lifestyle factors. These were examined in the current study. METHODS: Information on herbal supplement use and health and lifestyle characteristics was obtained by postal questionnaire, sent to a sample of the adult population in Northwest England. RESULTS: In summer 2001, 70.5% (15,465/21,923) of questionnaires were returned. The mean age of responders was 49.8 years (SD 17.57) and 45.2% (6,986/15,465) were men. The percentage taking at least one herbal supplement was 12.8% (1,987/15,465). Users of herbal supplements were more likely to be younger, female, white, and to own their home. Herbal supplement use was not strongly associated with any health and lifestyle variables examined. Weak associations were found with physical activity, psychiatric caseness, and use of prescribed medications. The most common herbal supplement was evening primrose oil, taken by 7.7% (1,186/15,465) of respondents (12.7% of women and 1.1% of men). CONCLUSIONS: More than one in ten adults were taking herbal supplements, with evening primrose oil, the most common supplement, used mainly by women. Individual characteristics such as age, sex, ethnicity, and social class influenced the use of herbal supplements, but there was no evidence that this substituted for conventional medical care. The evidence base to support some popular herbal supplements is weak. Large well-designed trials are needed to quantify the value of herbal supplements to health and well-being.