Chasing Hot Molecules

Headlines have called out red wine’s resveratrol as a potential agent for extending both life and health. Carrots’ beta carotene was thought to be a wonder antioxidant that could combat cancer. More recently people have started popping vitamin D pills at ever higher doses, hoping to ward off everything from stroke to diabetes. And the omega-3 fatty acids in fish oils have been heralded as heart and brain healthy. Micronutrientsvitamins and mineralsare compounds that people need to ingest in small amounts to prevent disease and maintain health. Once-common nutrition-related diseases such as scurvy and rickets can largely be prevented through varied diets, supplements, and the fortification of foods. Those successes have fueled the notion that if enough of a micronutrient is good, more might be better. Researchers have followed up on healthful hypotheses linking high doses of micronutrientsand other compounds found sparingly in foodswith chronic disease prevention. But in the randomized, controlled clinical trials needed to validate such connections, the results so far have shown mixed, contradictory findings or even unexpected harms. The boom and bust cycle confuses health-conscious consumers and has prompted some researchers to begin to question whether preventive supplements can ever stand up to the scientific scrutiny of clinical trials. The promise of a pill that would prevent cancer, heart disease, or any of a number of chronic diseases is an alluring goal, but the chemistry of preventing these diseasesand the complicated ways in which molecules and mixtures behave in the body may put such prevention pills out of reach.