Tuesday, July 08, 2008 . 7/08/2008

Live Longer: The One Anti-Aging Trick That Works

The formula is simple: Eat less. It could add years to your life, several experts now say. And done in moderation, it could at least help you live a more healthy life.

The only question is: Will the average person do it?

While little short of a nip-and-tuck will make you look younger, calorie restriction, as it is called, is as close to a real Fountain of Youth as any known technique comes. Even scientists who are cautious about anti-aging hype say it works, both by cutting risks for some diseases and by allowing all body cells, somehow, to hang in there longer.

"There is plenty of evidence that calorie restriction can reduce your risks for many common diseases including cancer, diabetes and heart disease," says Saint Louis University researcher Edward Weiss, who last week announced a new study that brings fresh understanding to how it works. "And you may live to be substantially older."

The numbers

Here's a rough rule of thumb that many experts generally agree on now: Eat 15 percent less starting at age 25 and you might add 4.5 years to your life, says Eric Ravussin, who studies human health and performance at the Pennington Biomedical Research Center in Louisiana.

One important caveat: Ravussin's estimate is based mostly on studies of other animals and only preliminary research in humans. But the work by Weiss and others is unlocking the mysteries of aging and suggesting the animal studies apply to humans.

"There is absolutely no reason to think it won't work," Ravussin told LiveScience.

Perhaps even more promising, though in early stages of research, are drugs designed on the basis of what's been learned from calorie-restriction studies. Those drugs would target human cells to deliver the same benefits, turning off bad things and turning on good things to extend cell life in general, or offer new therapies and cures to vexing diseases like Alzheimer's and cancer.

If you can hang in there until these promising new drug therapies are developed, you may live in a world where lifespan increases by 10 to 15 years, researchers say.

Don’t plan on living to be 200, Ravussin said, "but I think we're going to gain quite a few years."

Most Sunscreens Fail to Protect

The Environmental Working Group (EWG), a Washington-based research group and habitual gadfly to the business world, has found that 4 out of 5 of the nearly 1,000 sunscreen lotions analyzed offer inadequate protection from the sun or contain harmful chemicals. The biggest offenders, the EWG said, are the industry leaders: Coppertone, Banana Boat and Neutrogena.

While 3 out of 3 industry leaders are rather upset with the EWG report, and while some dermatologists criticize it for hyperbole, the report does underscore several long-standing health concerns:

Sunscreens do not offer blanket protection from the sun and do little to prevent the most deadly form of skin cancer; reliance on them instead of, say, a hat and protective clothing, might be contributing to skin cancer; and the Food and Drug Administration has yet to issue any safety standards, mysteriously sitting on a set of recommendations drafted 30 years ago.

Subcutaneous homesick blues

Sunlight contains ultraviolet radiation, largely in two forms: UVA and UVB. Aside from sunburn, UVB exposure causes the most common forms of skin cancer — basal cell carcinoma, which is rarely deadly and mostly only disfiguring, and squamous cell carcinoma, which can turn deadly about 1 percent of the time.

UVA penetrates the skin more deeply and causes wrinkling. Recent research, however, has found that UVA exacerbates the carcinogenic effects of UVB and might cause skin cancer itself.

Most sunscreens block only UVB. And the SPF system, short for Sun Protection Factor, refers only to UVB. SPF provides an estimate of a lotion's level of sunburn protection. If you start burning in about 30 minutes, then SPF 15 will allow you to stay in the sun 15 times longer before getting burned, in theory.

SPF of 1 zillion

Total UV protection is within reach and has been used for millennia. It's called clothing. Unfortunately this isn't so convenient when summertime fun calls for minimal clothing.

The EWG report takes an ax to the loose SPF claims. Almost all sunscreen lotions contain chemicals that, perhaps counter-intuitively, breakdown in the presence of sunlight. But in fact this is how they block UVB from penetrating the skin, like a castle wall protecting against cannonballs until the wall crumbles.

Notions of all-day protection, as some sunscreen products claim, or even several hours of protection are ludicrous, the EWG said, because most sunscreens start deteriorating in as quickly as 15 minutes. This doesn't even account for sweat and casual rubbing, further reducing protection.

Also, few sun-worshipers use the recommended shot-glass-amount of lotion with each application. We merely think we are protected; few really are.

Controversy, not just skin deep

The EWG also trashed any lotion containing harmful chemicals that can easily penetrate the skin. Oxybenzone, which blocks UVA, is a main offender. The U.S. Centers for Disease Control and Prevention has found oxybenzone in the urine of just about everyone tested.

This chemical can promote DNA damage in the presence of sunlight. Oxybenzone and similar cancer-causing chemicals in sunscreens contribute to the minority view that sunscreens actually cause more and deadlier cancers than they prevent. Several small studies have found an increased risk of malignant melanoma, by far the deadliest form of skin cancer, among regular users of sunscreens.

Many zinc-based protects appear to be safe, according to the EWG. Until the FDA breaks its silence and offers some guidance, there's the EWG list of recommendations at http://www.cosmeticsdatabase.com/special/sunscreens2008. Or you can move to Seattle.

Labels: science