By Roger Highfield (Filed: 29/10/2002)

Even middle-aged people can keep their heart young if they eat less, according to a study published today.

The demands of heartbeats over a lifetime takes a significant toll on muscle cells, one reason that heart disease is a major killer.

Now it has been found that middle-aged mice put on a calorie-restricted diet show a remarkable upturn in heart health in old age, according to a team from the University of Wisconsin-Madison, led by Profs Tomas Prolla and Richard Weindruch.

"Caloric restriction just retarded the whole ageing process in the heart," said Prof Prolla, whose group studied nearly 10,000 genes at work in the heart to learn how the pattern of use changed with time.

"The most surprising thing to me," he said, "is that caloric restriction, even when started in middle age, has a very strong effect on changes that occur with ageing."

The work, with colleagues at the University of Alabama, Birmingham, represents the first global analysis of the way genes are used in the ageing heart and is published today in the Proceedings of the National Academy of Sciences.

Caloric restriction, where diets remain nutritious but are reduced in calories, is the only known way to extend lifespan, according to a range of studies.

In this study, aged hearts from mice raised on low-calorie diets after 14 months old showed nearly 20 per cent less age-related gene use changes than aged hearts from mice on normal diets.

Cutting calories can confer significant health benefits for the heart and extend its working life, according to the results, by exerting influence on the genetic programme that governs heart cells.

For example, genes that play a role in increasing the size of heart cells, a condition that often precedes heart disease, come into play as the hearts age in animals on a regular diet, said Prof Prolla.

But caloric restriction in mice inhibited the genes involved in cell death.

The middle-aged mice had calories gradually reduced by up to 40 per cent.

-- Anonymous, October 28, 2002