When it comes to staying young, a low-calorie diet tops exercise, reports Reuters Health of research from Washington University in St. Louis, Mo.
We're not saying exercise is bad for you. While it can definitely help you to live longer by lowering your risk for obesity, diabetes and heart disease, only cutting calories appears to slow down the primary aging process.
Why? A nutritionally balanced but low-calorie diet lowers concentrations of T3, a thyroid hormone that controls body temperature and cell metabolism. Most important, T3 appears to curtail the production of free radicals. Restricting calories also lowers levels of the inflammatory protein tumor necrosis factor (TNF)-alpha. It's the combination of the two--lowering T3 and TNF levels--that seems to be responsible for slowing the aging process, reports Reuters Health.
Previous research by this same team has shown that while exercise and a low-calorie diet protect lab animals from age-related diseases, it's only the calorie reduction that actually slows down aging.
This latest study involved 84 human participants, 28 of whom voluntarily consumed a calorie-restricted diet of 1,800 calories a day for three to 15 years, 28 sedentary adults who consumed a typical Western diet and 28 endurance athletes who also ate a Western diet. Those on the Western diets ate about 2,700 calories a day. It was only in the restricted-calorie group that T3 concentrations dropped by about 30 percent, while other vital thyroid hormones (T4 and TSH) remained normal preventing hypothyroidism.
Lead study author Dr. Luigi Fontana said in a prepared statement that the results are "exciting because it suggests that calorie restriction has some specific anti-aging effects that are due to lower energy intake rather than to leanness."
The study findings were published in the Journal of Clinical Endocrinology and Metabolism.
--From the Editors at Netscape
