Substantially cutting calories from a normal diet could slow the ageing process and increase life expectancy, American scientists have found.
By Richard Alleyne, Science Correspondent
Published: 7:00AM BST 10 Jul 2009
Researchers have found that reducing calories by as much as 30 per cent – just above malnutrition levels – could reduce risks of developing heart disease or cancer by half and increase lifetimes by nearly a third.
The extreme diet could add an extra 25 years to the average life in Britain with the vast majority of people living to their 100th birthday.
However the increased life expectancy comes at a price – each individual would have to have a specially tailored diet, probably made from milk protein and corn oil, that kept them just above malnutrition levels and involve numerous vitamin and mineral supplements.
The dramatic predictions come from an ongoing 20-year-long study of monkeys – one of man's closest relatives – and the effects a calorie-restricted (CR) diet had on their health and lifespan.
Scientists, who have found survival rates of the CR monkeys to be three times that of their normally fed primates, believe the results would hold for humans.
The team from the University of Wisconsin, who published their findings in the journal Science, began their study in 1989 to see if a restricted diet – already shown to work in mice – would have an effect on the lifespan of more sophisticated mammals.
They have been following the lives of 76 macaques, all of which were enrolled as adults up to 14 years-old and normally have an average lifespan of 27 years.
For the first three to six months, the animals were observed to see how much food they would naturally eat – and then half of them were put on the extreme diets that cut their calorie count by 30 per cent.
During the 20-year course of the study, half of the animals permitted to eat freely have survived, while 80 per cent of the monkeys given the same diet, but with 30 per cent fewer calories, are still alive.
The oldest surviving animal is now 29.
It was not just the length of life that improved in the monkeys, but also the quality of that life, said Prof Weindruch.
The incidence of cancerous tumours and cardiovascular disease in animals on a restricted diet was less than half that seen in animals permitted to eat freely, he said.
While diabetes or impaired glucose regulation is common in monkeys that can eat all they want, it has yet to be observed in any animal on a restricted diet.
In addition, the brain health of animals on a restricted diet is also better.
"We have been able to show that caloric restriction can slow the ageing process in a primate species," said Professor Richard Weindruch, of the University of Wisconsin.
He said the results should have "relevance in humans" as the macaques are "closely related to humans".
He said that the key to the diet was to make sure that it made it nutritious. The reason why historically people had died younger even though they ate less was because the diet was not nutritious.
"It is important that we are studying calorie restriction and not malnutrition, so there is a fine line between a low enough level of calories but still enough to provide adequate nutrition," he said.
"Just because humans may have been eating less previously, it does not necessarily follow that they were eating a complete, nutritious diet."
No comments:
Post a Comment