Food as Medicine: Nutritionists, Clinicians Disagree on Role of Chemopreventive Supplements

Call it a food fight: Nutritionists say a diet rich in fruits and vegetables reduces cancer incidence, but some clinicians say cancer can't be thwarted by food alone, that supplements make better chemopreventives. Both sides point to epidemiological data supporting their respective positions. Recently, papers that try to explain the biochemical mechanisms by which foods and some supplements work have only added to the complexity of the debate.

Beta carotene has been a rallying point. The antioxidant most often associated with carrots had been linked to reducing lung cancer rates.¹ But over time, the picture became less clear. "There were some contradictory studies ... with beta carotene," comments Marvin Legator, professor of preventive medicine and community health at the University of Texas Medical School at Galveston. "On one hand, you had some indications that it did decrease ... cancer .... And on the other hand, you had studies...