Eating a diet rich in fruit and vegetables is undoubtedly good for you and might help reduce the risk of various cancers. However, controversy persists over the benefits of taking pills to supplement your daily intake of vitamins and minerals. Supplementary β-carotene has already been associated with an increased risk of lung cancer in heavy smokers, and a recent study in the American Journal of Respiratory and Critical Care Medicine has again brought this issue to the fore.

Christopher G. Slatore and colleagues analysed the effect of long-term use of vitamin supplements on the incidence of lung cancer and found that no reduction in risk was associated with use of supplementary multivitamins, vitamin C, vitamin E or folate. Moreover, as Slatore explains, “[i]n contrast to the often assumed benefits or at least lack of harm, supplemental vitamin E was associated with a small increased risk of lung cancer” (http://ukpress.google.com/ 1 Mar 2008). This increased risk was mostly observed for current smokers.

Millions use these pills every day, often hoping for protection against cancer and chronic disease, but the supporting evidence is limited. Slatore believes that the results “should prompt clinicians to counsel patients that these supplements are unlikely to reduce the risk of lung cancer and may be detrimental” (http://news.bbc.co.uk/ 29 Feb 2008). Henry Scowcroft at Cancer Research UK emphasizes that the best way to reduce lung cancer risk is simply not to smoke: “There's no diet, or vitamin supplement, that could ever counter the toxic effects of cigarette smoke” (http://news.bbc.co.uk/ 29 Feb 2008), a view supported by Slatore. “If you have $100, you'd be better off to spend it on nicotine patches,” he said (http://seattletimes.com/ 29 Feb 2008).