Caloric restriction does not prolong life expectancy, but improves health

Studies on 23 year old Rhesus monkeys show that reducing calorie intake is not linked to increased years of life...
A diet with calorie restriction does not increase life expectancy, but improves health, according to a study done with monkeys and published Wednesday in the scientific journal Nature.

Caloric restriction is the practice of limiting daily calorie intake to between 10% and 40%, hoping to improve health and slow aging, a thesis supported by previous studies with rodents.

The research published today, started 23 years ago by a group of scientists from the National Institute on Aging in Baltimore (USA), shows that this type of diet does not have the ability to prolong life expectancy in monkeys, but acknowledges its positive effects on the health of these animals.

The scientists, led by Spaniard biologist Rafael de Cabo, reduced calorie intake by 30% for rhesus monkeys (Macaca mulatta) and evaluated the effects of this diet on specimens of different ages and sexes.

The study concluded that the life expectancy of the animals (average 27 years) neither increased among older monkeys, between 16 and 23 years old when they started the diet, nor even among the younger, under age 14 when the experiment began.

On the other hand, the researchers found that caloric restriction benefited the metabolism of monkeys. "We observed a general improvement in parameters associated with the typical diseases of aging, such as metabolic disorders (diabetes and obesity), cardiovascular and cancer," said the biologist.

The monkeys that consumed 30% fewer calories had lower levels of triglycerides, cholesterol and glucose levels, especially among males, as well as a "remarkably low" incidence of cancer among younger primates.

The research, which according to Rafael de Cabo, could continue for two more decades, will now aim to investigate the molecular and metabolic effects of calorie restriction on the bodies of these monkeys.

"The answer is very similar to other stress responses, so we could consider calorie restriction as a metabolic stress, which causes global adjustments in the body, and when it is kept up for a long period of time, causes profound health benefits," explained the biologist.

Moreover, the scientist hopes to compare their results with those obtained by the Wisconsin National Primate Research Center in a parallel survey, also carried out with monkeys and started in the 80s, which defends the ability of diet to prolong life.

Translated from the Portuguese version by:

Lisa Karpova

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Author`s name Timothy Bancroft-Hinchey