Published: Jan. 11, 2008
Updated: Jan. 11, 2008
The Jury is Still Out, but Food Sources Probably Win Over Pills
The controversy surrounding antioxidant supplements has soared to a new level. A review of studies published in a recent issue of the Journal of the American Medical Association says that taking certain antioxidants as supplements provides no health benefits and might even increase the risk of death.
The report contradicted previous findings, angered the multibillion-dollar supplement industry, and confused those who consume over-the-counter antioxidants every day. As many as 20 percent of Americans and Europeans take daily antioxidant supplements.
Now that a little time has passed since the study was published, it is time to take an objective look at the research, the fallout, and the practical implications for older adults.
Researchers in Denmark conducted a “meta-analysis” of more than 60 previous studies involving 232,606 subjects on the effects of antioxidants. Antioxidants are thought to block the damaging effects of free radicals on arterial walls as well as damage to cells that could cause cancer, but the benefits have never been totally accepted by the medical community.
The most alarming new finding was that beta-carotene, vitamin A, and vitamin E were associated with a seven percent, 16 percent, and four percent, respectively, increased risk of mortality. In the highest quality studies reviewed, antioxidant supplements overall were associated with a five percent higher risk of death.
Furthermore, there was no evidence that any of the three antioxidants provided measurable health benefits. Vitamin C and selenium taken separately did not have a negative effect on mortality rates. The authors concluded that “prevention (of medical problems) by beta carotene, vitamin A, and vitamin E cannot be recommended.” But there is another side to this story.
While objections from the supplement industry were to be expected, there was an equally vigorous defense of antioxidants from physicians and nutritionists who do not have a vested interest in dietary supplements.
UCLA Medical Center clinical dietitian, Dana Ellis says, “In the study, some people may have had a disease from which they were going to die anyway, whether or not they took a supplement. Also, a single vitamin supplement contains one compound. By eating a piece of fruit or vegetable that contains vitamin C, you may be getting additional compounds that have not yet been identified, all of which could have a protective effect on cells and tissues.”
Many older adults take vitamins and minerals, including the ones considered in these studies, for reasons other than longevity. For example, vitamins A, E, and C, as well as selenium, are routinely recommended in hopes of preventing or delaying age-related macular degeneration.
Ellis warns about reading too much into this study. “Since the interpretation of the new study is still in question, it would be irresponsible to tell people not to take vitamin supplements. Vitamins and minerals are always better when taken in food rather than pills, but even this report hints that the evidence is at best unclear in terms of a detrimental effect.”
"One strong conclusion emerges from the somewhat confusing published literature about nutritional supplements -- it cannot be assumed that the benefits from a nutrient taken in supplement form will be equal to that observed when it is consumed from food sources," says Connie Bales, PhD, a Duke dietitian.
"Yet another beta-carotene study published in the March 2007 Archives of Opthalmology has found that this nutrient, long known to benefit the eyes when consumed from carrots, does nothing to prevent age-related macular degeneration -- a leading cause of blindness in older adults -- when consumed in supplemental form.
"This does not mean that there is never an advantage to using nutritional supplements. For example, the absorption of the synthetic form of folic acid found in supplements or fortified foods is considerably better than that of food folate.
"In another example, the Institute of Medicine advises adults over age 50 to obtain vitamin B12 mainly from B12-fortified foods or supplements containing B12. This is because age-related loss of stomach acid in some older individuals may reduce the availability of B12 from food sources.
"Generally speaking, consumers who want to take a supplement should consider a multivitamin preparation that supplies about 100 percent of the daily value for most vitamins and minerals listed on the label. Furthermore, because some supplements may interact with medications, consumers are best advised to consult with their physician, pharmacist, or nutritionist before starting a nutritional supplement."
If you are not taking antioxidant supplements and your physician gives you a clean bill of health, there is probably no reason to start. A well-balanced diet may be all you need, although older adults do tend to develop dietary deficiencies. Ask your doctor if you should take one or more supplements.
Ellis and other experts say, however, that if you have been taking antioxidant supplements all along, continue to do so until there is more compelling evidence to stop. Stay tuned...