Do Vitamins Keep Us Young?
For years, the popular belief was that oxidative damage causes aging: highly reactive molecules called free radicals damage cells and interfere with the functioning of tissues and organs. According to the theory, this rampant oxidation mangles more and more lipids, proteins, snippets of DNA, and other key components of cells. Eventually, the entire organism is compromised.
The early thinking was that isolated antioxidants, like vitamin C or beta carotene, would combat this process and prevent chronic diseases. The marketing hype for antioxidants escalated; today the word pops up on the labels of countless dietary supplements, and in countless TV ads and websites.
As a result, 52 percent (!!) of Americans take antioxidants daily, mostly as multi-vitamin supplements.
New Research Challenges the Antioxidant Myth
The article notes that recent experiments show that the increase in certain free radicals correlates with longer life, not shorter. In some circumstances, free radicals seem to signal cellular repair.
So far, these experiments have been conducted with mice and worms. If the results are confirmed, they suggest that taking antioxidants as vitamin supplements could do more harm than good.
Even before these new experiments, scientific studies questioned whether multivitamin supplements were really helping. In 2007, the Journal of the American Medical Association published a systematic review of 68 clinical trials, which concluded that antioxidant supplements do not reduce the risk of death.
When the authors limited their review to the trials that were least likely to be affected by bias -- examining only those in which assignment of participants to their research group was clearly random, and neither investigators nor participants knew who was getting which pill -- they found that certain antioxidants were linked to an increased risk of death, up as much as 16 percent.
Emerging Consensus Against Vitamin Supplements
The American Heart Association and the American Diabetes Association now advise people not to take antioxidant supplements, except to treat a diagnosed vitamin deficiency. I stopped popping multivitamins last year, but I take 1000mg of vitamin D3 ever since my internist said my blood work showed a deficiency.
Demetrius Albanes, a senior investigator at the National Cancer Institute says:
The literature is providing growing evidence that these supplements -- in particular at high doses -- do not necessarily have the beneficial effects that they have been thought to. We've become acutely aware of potential downsides.I checked with a few publications I have in my home offfice. The Wellness Reports: Dietary Supplements published by the University of California / Berkeley notes that its newsletter no longer recommends supplementary vitamins C and E and beta carotene. The combination of these vitamins found in food does the most good, it says:
Antioxidants are an essential part of the chemistry of life, but so far those sold as supplements have not lived up to their promise -- and certainly not to the hype.I have a Harvard Medical School Special Health Report, The Truth about Vitamins and Minerals, that draws the same conclusion.
Changing Theory of Aging
David Gems, an assistant director with the Institute of Healthy Aging at the University College London, is one of the scientists whose recent studies on free radicals is described in the Scientific American's new article. His conclusions suggest that aging is far more intricate and complex than the antioxidant theorists imagined.
Gems believes the evidence points to a new theory in which aging stems from the overactivation of certain biological processes involved in growth and reproduction. No matter where the new research ends up, Gems says, "the constant drilling away of scientists at the facts is shifting the field into a slightly stranger, but a more real place. It's an amazing breath of fresh air."