An apple a day really could keep the doctor away – as long as you don’t throw away the peel.
The chemical behind the apple skin’s waxy shine has been credited with a host of health benefits from building muscle to keeping the lid on weight.
Ursolic acid also keeps cholesterol and blood sugar under control, meaning an apple a day could do wonders for all-round health.
Researcher Christopher Adams said: ‘Ursolic acid is an interesting natural compound. It’s part of a normal diet as a component of apple peels.
‘They always say that an apple a day keeps the doctor away…’
Dr Adams, a US expert in how hormones affect the body, set out to find a drug that stops muscles from wasting, keeping pensioners strong as they age and cutting their risk of painful falls and hard-to-heal fractures.
He said: ‘Muscle wasting is a frequent companion of illness and ageing.
‘It prolongs hospitalisation, delays recoveries and in some cases events people from going back home.
‘It isn’t well understood and there’s no medicine for it.’
In order to remedy the situation, Dr Adams, of the University of Iowa, studied the genetic changes that occur when muscles waste or atrophy.
He checked a pool of 1,300 chemicals for one that would counter the changes – and hit on ursolic acid.
The researcher then supplemented some mice’s normal diet with small amounts of the compound and subjected them to a battery of health tests.
The creature’s muscles got bigger and their grip became stronger.