An apple a day keeps your body toned and slender

London: An apple a day keeps the doctor away, so goes the old saying. Now, researchers claim to have found out the exact reason — the fruit helps keep one`s body toned and slender by boosting muscles and fighting the flab.

A new study by the University of Iowa has found that ursolic acid- a substance found in the peel- has natural body building qualities and could help people keep a toned, slender body. And, it could even help with diabetes.

In experiments, the researchers discovered that it boosts muscle growth by up to 15 per cent and reduces body fat by more than a half. It also has health giving properties- reducing blood sugar levels, cholesterol and harmful fatty acids, `The Daily Telegraph` reported.

Lead researcher Christopher Adams said the substance could be especially useful in the elderly who naturally lose body muscle, known as atrophy.

He said: "The old saying goes that `an apple a day keeps the doctor away`. Muscle atrophy causes big problems. It`s also very common- it affects most people at some point in their lives, during illness or ageing. But, there`s no medicine for it.

"We studied muscle gene activity in people with atrophy and used that information to find chemicals that might block atrophy. One of those chemicals was especially interesting. It`s called ursolic acid and it`s particularly concentrated in apple peels."

The study, published in the `Cell Metabolism` journal, showed that ursolic acid reduced muscle wasting in mice. The researchers believe the substance works by reprogramming genes that cause muscle wasting and fat build up.

"Interestingly, although ursolic acid increased muscle weight in mice, it did not increase total body weight, and further investigation showed that mice fed ursolic acid had less body fat than mice that were not fed the compound," he said.