Mayo Clinic Proceedings January...( ROCHESTER Minn. -- Featured articles...)

ROCHESTER, Minn. -- Featured articles from the January issue of Mayo Clinic Proceedings include the effects of antioxidant supplements on cancer, guidelines for workplace drug screening and the safety and effectiveness of nasal spray flu vaccine.

Do antioxidant supplements reduce the risk of cancer and deaths related to cancer? Thats a question answered by Mayo researchers in an article in the January issue of Mayo Clinic Proceedings. While some trials have suggested that antioxidants have beneficial effects, results from other trials have been negative. It has been unclear which antioxidant compounts are more beneficial (or more harmful), and how individual antioxidants affect target organs and specific patient populations. To examine these issues, Mayo researchers conducted a systematic review on the topic.

Systematic reviews can provide reliable summaries of the research, and help understand why different studies give different results, says Victor Montori, M.D., senior author on the study and lead for Mayo Clinics Knowledge and Encounter Research (KER) unit. For the study, two authors reviewed all randomized trials on antioxidants for cancer prevention(1968-2005) and identified 12 clinical trials with a total eligible population of 104,196. The review yielded a number of interesting findings including:

• Overall, antioxidant supplementation did not reduce the risk of cancer.

• Beta carotene supplementation was actually found to increase the risk of smoking-related cancers, as well as cancer mortality, and thus should be avoided, especially by tobacco users.

• Vitamin E appeared to have no beneficial or harmful effects.

• Selenium supplementation was found to lower the risk of cancer in men (not in women), but the number of trials were few and further research is required. A large trial assessing the e
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