According to Kris-Etherton and colleagues (Circulation, 2004), approximately one third of Americans have used supplements.  Many people take megadoses of antioxidants like Vitamins A, C, E, beta-carotene and selenium in hopes of preventing or treating heart disease and cancer.  The question remains whether these supplements actually work and are they safe in the megadoses consumed by the general population?

To answer this question, let’s turn to most comprehensive evidence we have available so far.  In a recent meta-analysis, the Cochrane group looked at a total of 67 trials with 232,550 total participants.  Included were forty-seven trials with 180,938 participants that had a low risk of bias (adequate randomization, blinding and follow-up), twenty-one trials with 164,439 healthy participants, and forty-six trials with 68,111 participants with various diseases (gastrointestinal, cardiovascular, neurologic, ocular, dermatologic, rheumatoid renal, endocrinologic or other).

The results of these trials showed no beneficial effects on mortality (RR = 1.02; 95% CI, 0.99-1.06).  In fact, the trials with low risk of bias showed significantly INCREASED mortality (RR= 1.05; 95% CI, 1.02 to 1.08) in the participants taking antioxidants.  When the different antioxidants were assessed separately, INCREASED mortality was seen with Vitamin A (RR = 1.16; 95% CI, 1.10-1.24), beta-carotene (RR = 1.07; 95% CI, 1.02 to 1.11) and Vitamin E (RR = 1.04, 95% CI 1.01 to 1.07), and no detrimental effect with selenium (RR = 0.91; 95% CI, 0.76 to 1.09) or Vitamin C (RR = 1.06; 95% CI  0.94 to 1.20).  However, please review my other post about how Vitamin C is NOT effective for the common cold.

The bottom line is that the authors found NO evidence to support the use of antioxidants. In fact there was some evidence that excess intake of Vitamin A, E and beta-carotene may increase your chances of dying.  The current guidelines from the American Heart Association and U.S. Preventive Service Task Force are to eat a diet high in fruits and vegetables as a natural source of antioxidants.  There is no recommendation for adding supplements to your diet.  So please stop spending your money on unnecessary and potentially harmful supplements and just stick to a balanced diet. Your body will thank you for it.

References:

• Kris-Etherton PM, Lichtenstein AH, Howard BV, Steinberg D, Witztum JL, for the Nutrition Committee of the American Heart Association Council on Nutrition, Physical Activity, and Metabolism. Antioxidant vitamin supplements and cardiovascular disease. Circulation. 2004;110(5):637-641.
• Website: http://www.cochrane.org/reviews/en/ab007176.html; accessed 12/08