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Topic Name: Researchers proved severely restricted diet linked to physical fitness into old age

Category: Biomedical

Research persons: Tongjian You, Ph.D., William E. Sonntag, Ph.D., Xiaoyan Leng, M.D.,Ph.D.,Christy S. Carter, Ph.D.

Location: University at Buffalo, United States

Details

Severely restricting calories leads to a longer life, scientists have proved.

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 University at Buffalo 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.

Researchers on the study, in addition to You, were William E. Sonntag, Ph.D., and Xiaoyan Leng, M.D., Ph.D., from Wake Forest University School of Medicine, and Christy S. Carter, Ph.D., from the University of Florida and the Malcom Randall VA Medical Center in Gainesville.

The study was supported by grants from the National Institutes of Health.

About Researcher:

Tongjian You, Ph.D.
Assistant Professor, Department of Exercise and Nutrition Sciences

tyou@buffalo.edu
Farber G10
716-829- 3680 x222
716-829-3700 (fax)

Ph.D., Exercise Physiology, University of North Carolina, Greensboro, 2002
Post-doc, Obesity/Aging, Wake Forest University School of Medicine, 2004

Profile:

Before coming to UB, I was an Instructor in the Section on Gerontology and Geriatric Medicine, Department of Internal Medicine, with a cross-appointment in the Department of Physiology and Pharmacology at Wake Forest University School of Medicine.

Research Interests:

Adipose tissue metabolism. Metabolic and physical dysfunctions associated with obesity and aging. Metabolic and hormonal adaptations to diet and exercise.

About National Institutes of Health

The National Institutes of Health (NIH) is an agency of the United States Department of Health and Human Services and is the primary agency of the United States government responsible for biomedical research.

The Institutes are responsible for 28%—about $28 billion—of the total biomedical research funding spent annually in the U.S., with most of the rest coming from industry. The NIH is divided into two parts: the "Extramural" parts of NIH are responsible for the funding of biomedical research outside of NIH, while the "Intramural" parts of NIH conduct research. Intramural research is primarily conducted at the main campus in Bethesda in unincorporated Montgomery County, Maryland, and the surrounding communities. The National Institute of Aging and the National Institute on Drug Abuse are located in Baltimore, Maryland, and the National Institute of Environmental Health Sciences is in Research Triangle, North Carolina. The NIAID maintains Rocky Mountain Labs in Hamilton, Montana, with an emphasis on virology.

The predecessor of the NIH began in 1887 as the Laboratory of Hygiene. It grew and was reorganized in 1930 by the Ransdell Act into the National Institute of Health (singular at the time). Today it is one of the world's foremost medical research centers, and the Federal focal point for medical research in the U.S. The NIH, comprising 27 separate institutes, centers and the Office of the Director, is part of the United States Department of Health and Human Services. The current NIH Director is Elias Zerhouni.

The goal of NIH research is to acquire new knowledge to help prevent, detect, diagnose, and treat disease and disability, from the rarest genetic disorder to the common cold. The NIH mission is to uncover new knowledge that will lead to better health for everyone. NIH works toward that mission by: conducting research in its own laboratories; supporting the research of non-Federal scientists in universities, medical schools, hospitals, and research institutions throughout the country and abroad; helping in the training of research investigators; and fostering communication of medical and health sciences information.

About University at Buffalo

The University at Buffalo is a premier research-intensive public university, the largest and most comprehensive campus in the State University of New York. The School of Public Health and Health Professions is one of five schools that constitute UB's Academic Health Center. UB's more than 28,000 students pursue their academic interests through more than 300 undergraduate, graduate and professional degree programs. Founded in 1846, the University at Buffalo is a member of the Association of American Universities. The university is in full compliance with mandates of state and federal regulatory agencies pertaining to the humane use and care of research animals.