New progress against aging

Oxidation, super-dieting, and you
Oxidative stress -- the buildup of too many free radicals in cells -- may explain the benefits of caloric restriction. More energy means more calories. Do more calories mean more disorder?That's the opinion of Richard Weindruch, who is studying calorically restricted monkeys at the University of Wisconsin- Madison. Writing in Scientific American, Weindruch suggested that mitochondria are the major source of free radicals. Mitochondria are tiny "factories" inside cells that make adenosine triphosphate (ATP), a chemical that powers a wide range of cellular activities.

Weindruch wrote that mitochondria seem to inadvertently make free radicals while producing ATP. The free radicals, in turn, damage the mitochondria, and the damaged mitochondria make more free radicals. Eventually the cycle of damage becomes a slippery slope that we call "aging." (See "Caloric Restriction and Aging" and "Oxidative Stress, Caloric Restriction, and Aging" in the bibliography).

It's not clear why reducing caloric intake should reduce the amount of free radicals produced in cells, although there are some candidate explanations. But George Roth, who heads the National Institutes of Aging study on calorically restricted monkeys, suspects that free radicals are part of the more general story of aging.

As Roth sees it, aging is a reduction in the amount of order in living systems, which require a high degree of order. He says that more energy, in the form of more calories, creates more disorder (which scientists call entropy). He suggests that caloric restriction "slows the energy flux through the organism so we disorder at a slower rate."

Although it might seem that more energy would cause more order (after all, it takes a lot of effort to clean a messy room) remember that adding energy to the atmosphere, for example, actually increases the amount of disorder -- and could eventually cause a hurricane. And when you remove enough thermal energy to lower the temperature to almost absolute zero, things get so orderly that almost nothing happens, and atoms actually fuse.

Roth's point is that living cells depend on order. Think of the incredible complexity and specificity of the DNA in your chromosomes. So in the broadest sense, more disorder equals more destruction and less ability to function -- in other words, aging.

Should you take antioxidants?
We were hoping you wouldn't ask the million-dollar question. Antioxidants -- including vitamins A, C and E -- are widely considered to be antidotes to aging, and there's some evidence that they work. The Why Files won't suggest that you take antioxidants. But we will tell you that in 1997, when a panel of prominent aging researchers (including some of the experts interviewed here), was asked whether they took antioxidants, they all raised their hands in unison.

Read all about it in our bibliography.

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