Severely restricting calories leads to a longer life /slows physical disability

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Severely restricting calories leads to a longer life

http://www.news-medical.net/?id=31740

New research now has shown for the first time that such a diet also

can maintain physical fitness into advanced age, slowing the

seemingly inevitable progression to physical disability and loss of

independence.

The study, using a rat model of life-time caloric restriction,

showed that the diet reduces the amount of visceral fat, which

expresses inflammatory factors that in humans cause chronic disease

and a decline in physical performance and vitality across the

lifespan.

The study appears in the October issue of Journals of Gerontology

Series A: Biological Sciences and Medical Sciences.

Have we finally discovered the Fountain of Youth?

No. But we may be getting a little closer.

" This is the first study to report that caloric restriction reduced

production in visceral fat of the inflammatory cytokine IL-6 and

enhanced performance on overall physical function assessments, " said

Tongjian You, Ph.D., assistant professor of exercise and nutrition

sciences in the UB School of Public Health and Health Professions

and principal investigator.

" In addition, rats that ate a normal diet lost a significant amount

of lean muscle mass and acquired more fat, while calorie-restricted

rats maintained lean muscle mass as they aged. "

The study was conducted with male rats in three age groups -- 18, 24

and 29 months, comparable to ages 50-70 years in humans -- that had

been fed either a normal or

40-percent calorie-restricted diet from birth. The animals were put

through tests to determine grip strength, muscle tone, stamina and

swimming speed. Data also were collected on whole body mass, lean

body mass, fat mass, percent body fat, the ratio of fat-to-lean body

mass, amount of visceral fat and the amount of pro-inflammatory

cytokines and C-reactive protein, a marker of chronic inflammation.

Results showed that animals on the restricted calorie diet had

significantly higher physical performance scores than animals fed a

normal diet. They also had less fat, a lower fat-to-lean ratio, and

lower adipose tissue secretion of IL-6 and circulating levels of C-

reactive protein.

The stumbling block on this path to remaining forever young is that

humans could not adhere to such a severe diet.

" Based on an average of 2,000 calories per day for adult women and

2,500 for men, cutting by 40 percent would mean surviving on 1,200

and 1,500 calories per day, respectively, said You.

" It's very difficult for people to maintain that type of diet for

short periods of time, and it would be nearly impossible over a

lifetime, while staying healthy. Starting on a diet like that in the

senior years would be harmful. "

You said that a more moderate form of caloric restriction, 8

percent, is achievable in humans, based on recent findings, and may

have positive effects on specific oxidative stress and inflammatory

biomarkers.

" Preclinical testing of this 8-percent regimen could be informative

and beneficial in translating to humans, " he said.