Biomarkers Suggest Dieting Alternatives for Longevity

A study on aging has revealed that men with lower body temperatures, lower blood insulin levels, and higher blood levels of dehydroepiandrosterone sulfate (DHEAS) as they aged tended to live longer without reducing calories, and that monkeys with these characteristics lived longer if their caloric intake was severely restricted. These findings were reported in the August 2, 2002, issue of Science.

Investigators from the US National Institute of Aging (Bethesda, MD, USA) compared more than 700 healthy men, aged 19 to 95, with 60 rhesus monkeys, aged five to 25. The men were divided into two groups, based on whether they were in the upper or lower halves of the population for each of the three biomarkers--body temperature, blood insulin levels, and blood levels of DHEAS. The monkeys also were divided into two groups. One group was allowed to feed freely, typically consuming between 500 to 1,000 calories daily. A second group was fed a diet composed of at least 30% fewer calories than consumed by the unrestricted monkeys.

Biomarker and mortality data were collected on the men over a 25-year period, and biomarker data were gathered on the monkeys for five years beginning in 1987. Deaths among the monkeys have been tracked for more than 15 years.

Analysis of age-adjusted data revealed that among the participating men, those who had lower body temperatures, lower blood insulin levels, and higher blood levels of DHEAS as they aged tended to live longer. The calorically restricted monkeys showed a similar trend, and had half the death rate of monkeys allowed to feed freely.

None of the men, who reported consuming an average of 2,300 calories daily, was on a calorically restricted diet. "The fact that these men apparently were not practicing caloric restriction is important because it means there may be other ways to achieve biological hallmarks without having to undergo drastic dietary changes,” said Dr. George Roth, senior guest scientist at NIA and lead author of the study. "Although we do not yet know what these pathways are, this finding suggests it may be possible to develop compounds that offer the benefits of caloric restriction without having to resort to it.”




Related Links:
NIH/National Institute on Aging