Research casts doubt on effectiveness of calorie restriction in humans

Posted on 2008-09-25 06:50:30 in Longevity | Longevity and Age Management | Nutrition |

Recent study results suggest that calorie restriction may not be as effective at extending human life as it is at extending the lifespan of rodents.

Numerous animal studies have suggested that calorie restriction can significantly lengthen lifespan. Exactly how calorie restriction promotes longevity remains unclear, although pathways involving insulin-like growth factor-1 (IGF-1) have been implicated in many animal models, with levels of IGF-1 dropping by as much as 40% in some animals on a calorie restricted diet.

With this is mind, Luigi Fontana, assistant professor of medicine at Washington University at St Loius, and colleagues studied whether calorie restriction in humans had a similar effect on IGF-1 levels to that seen in animals. Their results showed that calorie restriction had no effect at all upon IGF-1 levels in humans.

This troubled the researchers as they could not understand why such different results had been obtained in rodents. However, the researchers also knew that protein intake can influence IGF-1 levels, so they began to investigate what effect eating less protein would have. This led the researchers to discover that protein does indeed have a major impact on IGF-1 levels. They found that IGF-1 levels plummeted dramatically if people following a calorie-restricted diet obtained just 10% of their calories from protein.

These findings suggest that humans wanting to lengthen their lifespan should possibly be thinking about lowering protein consumption instead of cutting calories.  "It's much easier to restrict protein than to restrict calories," Fontana says in a news release issued by Washington University. "If our research is on the right track, maybe humans don't need to be so calorie restricted. Limiting protein intake to 0.7 or 0.8 grams per kilogram per day might be more effective. That's just a hypothesis. We have to confirm it in future studies."

Fontana L, Weiss EP, Villarreal DT, Klein S, Holloszy JO. Long-term effects of calorie or protein restriction on serum IGF-1 and IGFBP-3 concentration in humans. Aging Cell. 2008;7. Doi: 10.1111/j.1474-9726.2008.00417.x

News release: Researchers note differences between people and animals on calorie restriction. Washington University in St. Louis. September 24th 2008.  

 


Health Headlines

In a lab animal model, booming gut flora spawned by the Western diet is linked to obesity.
International study reaffirms importance of resolving the income gap between the richest and poorest people in developed countries.
Switzerland-based research team assesses the metabolic effects of dark chocolate consumption on energy, gut microbiota, and stress hormones.
UCLA researchers find disability rates in Americans entering their 60s are on the rise, potentially fueled by the overweight/obesity epidemic.
Genetic clues to longevity discovered among a homogenous ethnic population.
Rush Alzheimer's Disease Center (USA) researchers find that a loss of muscle strength raises risk of Alzheimer’s Disease and mild cognitive impairment.
Stroke risk may rise in those with common infectious pathogens such as Chlamydia pneumoniae, Helicobacter pylori, and herpes simplex viruses.
First study in humans links bisphenol A (BPA) exposure to male sexual function problems.
Simple steps in the community can promote walking among residents.
Study finds that people who are dissatisfied with their workplace bosses not only take more sick leave, but are at increased risk of suffering a heart attack.
Looking for an Anti-aging Doctor?

upcoming Events

U.S. Events
congresses
Las Vegas
fellowships
fellowships
symposium
workshops
  • Advanced Hormone Symposium
    Chicago, IL | Oct. 8-10, 2010

VIDEO: Brain Age Workshop
Dr. Eric Braverman, Director of The Place for Achieving Total Health (PATH Medical), Chairs the Brain Age Workshop taking place Dec. 9, 2009. Held in conjunction with the Winter Session of the 17th Annual World Congress on Anti-Aging Medicine & Regenerative Biomedical Technologies. The Brain Age Workshop features presentations on Brain Mind Assessment via Neuropsychological Analysis, Movement Deficiency Syndrome, Hormones and the Brain, Nootropic Drug Mechanisms, and Traumatic Brain Injury. View this video to learn about Dr. Braverman’s brain-based model of aging and age modulation.

International Events
See all events »