Living Past 100 Is Not Related to Exercise.

Living past 100 soon could become a more commonly reachable goal, says Nir Barzilai of the Albert Einstein College of Medicine, Bronx, N.Y. Delivering the keynote speech at Harvard University's Nutrition and Obesity Symposium on Longevity and Aging, Barzilai challenged the common wisdom that the secret to a long life is a healthy lifestyle. The real secret, he indicates, lies in the genes.

Barzilai's work examines the difference between chronological and biological age--literal years vs. the relative health of the body. The subjects who show the greatest discrepancy hold the key to genetic research that could make aging a treatable condition, and those cases are not always found where one might expect.

He cites the famous example of the Kahns of Manhattan, who were the world's longest-lived quartet of siblings--all have died since 2005, the youngest at age 101. None were especially health conscious: Irving still worked a high-stress Wall Street job after turning 100, and one of his sisters was a smoker for 90 years (outliving all the doctors who advised her to quit, Barzilai noted).

A larger study of centenarians showed the Kahns were not unique: of the group studied, 50% were overweight; 60% of the men smoked; less than half exercised; and only two percent were vegetarian. "As a group, they didn't do anything that we tell our patients to do," Barzilai relates.

Further research shows that none of these centenarians had a "perfect genome"; many carried a genetic risk for Parkinson's and other...