In the search for ways to lengthen the human lifespan and extend good health further into old age, scientists had until now found only one program that demonstrated real promise: severe calorie restriction. However, researchers at Harvard have touched upon a discovery that Americans might find a great deal more palatable.

Resveratrol, a compound found most abundantly in red wine, has been shown to stimulate an anti-aging enzyme active within living cells. This enzyme protects cells from stresses that would ordinarily kill them off, thus extending their life span.

But don't go prescribing yourself a nightly glass of red wine just yet. The study is preliminary and more testing will be required before the results of this study would make their way into the doctor's office as clinical recommendations. Still, the potential this discovery holds is exciting.

"It is too early to say whether we will be successful in our goal of slowing or preventing diseases of old age," said Dr. David Sinclair, a researcher who led the study. "Certainly the results are encouraging and exciting. From here on, the idea of having a pill that could dramatically improve health and extend life is no longer completely in the realm of science fiction. Our discovery brings us one step closer to a day when we will have less to fear about growing old."

The effects of calorie restriction without the diet

The most significant finding in the research surrounding the aging process so far has been the study of calorie restriction. When mice were fed diets that were sufficiently nutritious but contained 30 percent fewer calories than normal, their life spans were expanded by 30 to 50 percent.

Even more important than longer life span is the fact that calorie restriction has been shown to delay diseases associated with old age in test animals as well. Knowing how difficult it would be for people to adhere to such a diet, scientists have been searching for another way to achieve the same effect.

Further research into the mechanics behind calorie restriction has found that it may have worked by activating certain enzymes called sirtuins. The next step was to find another way to stimulate them. In the Harvard study, which was published in August in the online edition of the journal Nature, researchers screened a large group of compounds to see whether they activated sirtuin.They were surprised to find that two of the chemicals did.

"There had never been a molecule that could mimic calorie restriction. So what were the odds? Pretty slim. In fact, few scientists thought it was even possible to find such molecules. Scientists are cynical by nature. We set out on a quest, but we didn't expect to uncover a Holy Grail," Dr. Sinclair said.

Gearing up for more tests ahead

The two chemicals belonged to a family known as polyphenols. Plants produce polyphenols in response to stress. The molecules appear to invoke a survival response within the plants' own cells.

The researchers tested more polyphenols to see if they activated sirtuin. They found several, including butein and fisetin, that worked well, but they found resveratrol to be the most effective in both yeast and human cells. Colleagues of the Harvard team have also tested these compounds on fruit flies and nematodes (worms) in still-ongoing studies and have seen similar results.

The cells in yeast, fruit flies, and nematodes have similar aging processes to human cells, so they are popular subjects for scientists studying the effects of various chemicals and stresses on aging. The next step is to test the compounds in mice, which the Harvard researchers are "gearing up" to do, Dr. Sinclair said.

"If the mice truly live longer, then I would anticipate starting human trials sometime shortly thereafter," he said.

Scientists are also developing synthetic compounds and testing them to see if they have the same effect as the natural ones. Because moderation is tricky for some, scientists and physicians hesitate to recommend a program of drinking more red wine. Its calories and addictive properties have the potential to do more harm than good.

Researchers' ultimate goal is to develop a drug that people could take in the form of a pill, avoiding alcohol altogether while increasing their chances of living longer without fear of chronic diseases such as heart disease, cancer, or Alzheimer's Disease.