Hungry and cold centenarians
Lower body temperature correlates with longer life expectancy
LifeSciencesToday based on materials from Washington University in St. Louis:
Restricting calories lowers body temperature, may predict longer lifespan
Scientists studying the relationship between nutrition and longevity have found new evidence that a low-calorie diet helps people live longer. A group of researchers from the Washington University School of Medicine in St. Louis reports in the journal Aging that significant calorie restriction leads to a decrease in central body temperature (Soare et al., Long-term calorie restriction, but not endurance exercise, lowers core body temperature in humans).
The new data correspond to those obtained in animal experiments. Mice and rats that receive fewer calories also have a lower body temperature, and these animals live significantly longer than their littermates who are on a standard diet.
Scientists compared the central body temperature of 24 people aged 53.7±9.4 years, practicing a diet with a reduced number of calories for at least 6 years, and the temperature of 24 people of the same age, prone to a standard Western diet with a high fat and calorie content. They also measured the central body temperature of 24 stayer runners of the same age to determine whether thinness, both in the case of athletes and those on a restricted diet, is associated with a lower body temperature or calorie restriction is necessary to lower it.
"The central body temperature of those on a calorie-restricted diet was on average 0.2 degrees Celsius lower, which seems to be a modest decrease. However, it is statistically significant and similar to the decrease that we observed in long–lived mice on a low-calorie diet," comments the results of the study, its head, Doctor of Medicine and Philosophy Luigi Fontana (Luigi Fontana). "Interestingly, athletes of the same age and the same build did not experience such a decrease in body temperature."
Everyone – from yeast and rodents to humans – benefits from calorie reduction. In simple organisms, calorie restriction can double or even triple life expectancy. It remains unclear how much calorie restriction can help increase a person's life expectancy, but those who practice a strict diet hope to step over the 100-year mark.
Those who follow a strict diet reduce their calorie intake by 25 percent or even more, but they carefully monitor the amount of vitamins and nutrients in their diet to avoid malnutrition. In this study, all representatives of the calorie restriction group are members of the CR (Calorie Restriction – Calorie Restriction) Society and call themselves CRONies (Calorie Restriction with Optimal Nutrition – Calorie Restriction with Optimal Nutrition).
The central body temperature is the temperature at which all the functions of the body can be carried out with maximum efficiency. The temperature of the human body is not the same at its different points, and internal indicators are usually higher than those obtained closer to the skin. Although the ideal central body temperature is 37.7 degrees Celsius, it varies from 36.7 to 38.2 degrees.
In this study, scientists measured the central temperature using ingested telemetry capsules that recorded and transmitted the internal temperature every minute.
Dr. Fontana is not inclined to jump to conclusions and emphasizes that he does not know whether a strict calorie restriction lowers body temperature or something else causes it to drop, but a lowered body temperature is one of the keys to increasing life expectancy in animals.
"We don't know if there is a causal relationship between these phenomena or if it's just a coincidence," he says. "But animal studies consistently confirm that organisms with a lower central temperature live longer."
Scientists also note that in an unrelated study, known as the Baltimore Longitudinal Study of Aging, it was found that people with a reduced central temperature, probably due to genetic reasons, live significantly longer than people with a higher temperature. Apparently, body temperature can be considered as a prognostic sign of life expectancy in humans, suggests Dr. Fontana.
It is not at all clear how much longer a person with a low temperature can live. Rodents on a low-calorie diet are known to live up to 50 percent longer, but this increase is calculated in months.
At the moment, animal models show that a simple decrease in body temperature is not enough to increase life expectancy. In mice and rats that regularly swam in cold water, the central body temperature dropped due to exposure to cold water. But these animals did not live longer than ordinary rodents. Dr. Fontana believes that, apparently, it is important how the temperature reduction is achieved.
"I don't think it will ever be possible to take a pill, or several pills, to lower the temperature and increase life expectancy, while remaining a smoker, being overweight and addicted to alcohol," he says. "However, it is quite possible to slightly reduce the amount of calories consumed, eat normal food, do simple physical exercises and take any drug that will provide the effect obtained with strict calorie restriction."
Portal "Eternal youth" http://vechnayamolodost.ru16.05.2011