A low-calorie diet can't prolong a person's life?
According to the results of a 25-year study on rhesus monkeys, constant maintenance on a low-calorie diet does not increase the life expectancy of these animals, which are genetically very close to humans. For a quarter of a century, experimental animals received 30% fewer calories than control group animals. Based on the results obtained, the authors concluded that two other factors have the most pronounced effect on life expectancy: good genes and a healthy, well-balanced diet.
According to Don Ingram, a gerontologist at Louisiana State University, who planned this study almost 30 years ago during his work at the US National Institute of Aging, the very idea that simply limiting the calorie content of the diet could prolong life seemed something out of the ordinary.
At the beginning of the study, there were already prerequisites indicating that a strong reduction in the caloric content of the diet for a long time can have a positive impact on life expectancy.
The results of the earliest studies on this issue have shown that starving roundworms live much longer than their well-fed counterparts. Studies on rats have also demonstrated that a low-calorie diet provides an extension of the youth of animals.
Later, scientists at the University of Washington suggested that a low-calorie diet reduces the internal temperature of the human body, thereby prolonging his life.
According to the results of a study by University College London, published in the journal Nature, it is not a low-calorie diet that increases life expectancy, but a diet with a high protein content.
Recently, scientists have received data according to which a low-calorie diet can trigger a genetic "domino effect" leading to a slowdown in the aging process.
In 2009, researchers at the National Primate Research Center in Wisconsin found that only 13% of rhesus monkeys kept on a very low-calorie diet died for age-related reasons, whereas for the control group kept on a normal diet, this figure was 37%.
Ingram believes that the experiment conducted by his colleagues has serious drawbacks. Firstly, the diets of both groups of animals cannot be called healthy. Their caloric content was provided by sucrose by 28.5%, whereas in Ingram's study, animals received only 3.9% of calories in the form of sucrose. Moreover, his monkeys, unlike Wisconsin macaques, received fish oil and antioxidants. The head of the Wisconsin study, Rich Weindruch, agreed that his wards were kept on a less healthy diet. Apparently, the results he obtained are due to the fact that a less caloric unhealthy diet is less harmful to the body than the same diet, but with a high calorie content.
Another disadvantage of the earlier study is the unrestricted access of animals to food. The macaques of Igram, on the contrary, ate a fixed amount of food per day. The result was a greater body weight of all Wisconsin monkeys compared to the animals of the corresponding study groups conducted by the US National Institutes of Health.
According to Ingram, when he and his colleagues started their study, it was believed that all calories were the same. To date, it has become obvious that the quality of calories consumed plays a key role.
Another possible explanation for the inconsistency of the results obtained may be genetic differences between the populations used. The monkeys involved in the US National Institutes of Health study are of Indian origin, while the ancestors of Wisconsin macaques descended from other genetic lines that lived in China and India.
Apparently, the molecular effects of a low-calorie diet are much more complicated than they seem. The researchers expected that manipulating the activity of certain genes would allow them to prevent the development of diseases and slow down the aging process. However, it turned out that these mechanisms vary greatly depending on the species to which the organism belongs.
Moreover, there is practically no evidence that a low-calorie diet is associated with slowing down human aging. According to the results of observational studies, centenarians, as a rule, have a normal body weight, and are not thin people who follow a low-calorie diet.
According to the gerontologist of the Albert Einstein College of Medicine, New York, communication with people who have crossed the 100-year milestone gives the impression that genetics plays a much greater role in longevity, and not the image and diet.
Article by Donald K. Ingram et al. The impact of caloric restriction on health and survival in rhesus monkeys from the NIA study is published in the journal Nature.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru according to Medical News Today:
Does Severe Calorie Restriction Help You Life Longer? Probably Not.
30.08.2012