Restricting calories lowers body temperature, may predict longer lifespan

May 11, 2011 By Jim Dryden, Washington University School of Medicine in St. Louis

(Medical Xpress) -- Nutrition and longevity researchers have found more evidence that eating less may help people live longer.

The research team at Washington University School of Medicine in St. Louis reports in the journal Aging that individuals who significantly reduce their have lower core body temperatures compared to those who eat more.

The new finding matches research in animals. Mice and rats consuming fewer calories also have lower core body temperatures, and those animals live significantly longer than littermates eating a standard diet.

The investigators compared core body temperatures of 24 people in their mid 50s who had practiced for at least six years to 24 others of the same age who ate a standard with higher calorie and fat intake. The researchers also measured core body temperatures in 24 endurance runners of the same age to determine if being lean — like both the calorie restriction group and the runners — was linked to lower body temperature or whether calorie restriction itself was necessary.

“The people doing calorie restriction had a lower average core body temperature by about 0.2 degrees Celsius, which sounds like a modest reduction but is statistically significant and similar to the reduction we have observed in long-lived, calorie-restricted mice,” says principal investigator Luigi Fontana, MD, PhD. “What is interesting about that is endurance athletes, who are the same age and are equally lean, don’t have similar reductions in body temperature.”

Organisms from yeast to rodents to humans all benefit from cutting calories. In simple organisms, restricting calories can double or even triple lifespan. It’s not yet clear just how much longer calorie restriction might help humans live, but those who practice the strict diet hope to survive past 100.

Those on calorie restriction cut their daily caloric intake by 25 percent or more, but they also carefully track vitamins and nutrients in the diet in order to avoid malnutrition. In this study, all of those in the group practicing calorie restriction were members of the CR Society, and they refer to themselves as CRONies (Calorie Restriction with Optimal ).

A person’s core body temperature is the temperature at which all of the functions in the body can operate with maximum efficiency. The temperature of the human body is not uniform throughout, and internal readings tend to be higher than those taken closer to the skin. Although the ideal core body temperature is considered to be 98.6 degrees Fahrenheit or 37.7 degrees Celsius, body temperatures vary from about 96 degrees to almost 100 degrees.

For this study, investigators measured core body temperature using telemetric capsules that participants swallowed, which then recorded and transmitted internal body temperatures every minute.

Fontana, a research associate professor of medicine at Washington University and a senior investigator at the Istituto Superiore di Sanità in Rome, Italy, says he does not know whether severely limiting calories is lowering body temperatures or whether something else is causing core temperature to drop, but he says the reduced temperature is a key to increased in animals.

“What we don’t know is whether there is a cause/effect relationship or whether this is just an association,” he says. “But in animal studies, it’s been consistently true that those with lower core body temperatures live longer.”

The researchers also note that in an unrelated study called the Baltimore Longitudinal Study of Aging, scientists found that men who had lower core body temperatures, probably for genetic reasons, lived significantly longer than men with higher body temperatures. So it appears body temperature may predict longevity in humans, too, Fontana says.

What is not yet understood is how much longer people with lower might live. Rodents on a calorie-restricted diet have been known to live up to 50 percent longer, but those increases can be measured in months.

For now, animal models suggest that simply lowering body temperature isn’t enough to increase lifespan. In mice and rats that regularly swam in cold water, core body temperature dropped due to exposure to the cold water. But those animals didn’t live any longer than normal rodents. Fontana says it appears that how lower temperatures are achieved is important.

“I don’t think it ever will be possible to be overweight and smoking and drinking and then take a pill, or several pills, to lower body temperature and lengthen lifespan,” he says. “What may be possible, however, is to do mild calorie restriction, to eat a very good diet, get mild exercise and then take a drug of some kind that could provide benefits similar to those seen in severe calorie restriction.”

More information: Soare A, Cangemi R, Omedei D, Holloszy JO, Fontana L. Long-term calorie restriction, but not endurance exercise, lowers core body temperature in humans. Aging, vol. 3 (3) March 2011. www.impactaging.com

Related Stories

Recommended for you

Forces from fluid in the developing lung play an essential role in organ development

January 23, 2018
It is a marvel of nature: during gestation, multiple tissue types cooperate in building the elegantly functional structures of organs, from the brain's folds to the heart's multiple chambers. A recent study by Princeton researchers ...

Anemia discovery offers new targets to treat fatigue in millions

January 22, 2018
A new discovery from the University of Virginia School of Medicine has revealed an unknown clockwork mechanism within the body that controls the creation of oxygen-carrying red blood cells. The finding sheds light on iron-restricted ...

More surprises about blood development—and a possible lead for making lymphocytes

January 22, 2018
Hematopoietic stem cells (HSCs) have long been regarded as the granddaddy of all blood cells. After we are born, these multipotent cells give rise to all our cell lineages: lymphoid, myeloid and erythroid cells. Hematologists ...

How metal scaffolds enhance the bone healing process

January 22, 2018
A new study shows how mechanically optimized constructs known as titanium-mesh scaffolds can optimize bone regeneration. The induction of bone regeneration is of importance when treating large bone defects. As demonstrated ...

Researchers illustrate how muscle growth inhibitor is activated, could aid in treating ALS

January 19, 2018
Researchers at the University of Cincinnati (UC) College of Medicine are part of an international team that has identified how the inactive or latent form of GDF8, a signaling protein also known as myostatin responsible for ...

Bioengineered soft microfibers improve T-cell production

January 18, 2018
T cells play a key role in the body's immune response against pathogens. As a new class of therapeutic approaches, T cells are being harnessed to fight cancer, promising more precise, longer-lasting mitigation than traditional, ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

dogbert
not rated yet May 11, 2011
I don't know why it should be surprising that lowering an organism's metabolic rate equates to longer life span. We should expect that.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.