Eating a medium-sized apple every day in your sixties can help protect against the infirmity that comes with old age, scientists have found.
The fruit contains a particularly beneficial flavonol called quercetin, just 10mg of which reduces the odds of frailty by 20 per cent, according to a study.
Up to 15 per cent of older adults experience frailty, a geriatric syndrome that leads to a greater risk of falls, fractures, disability, hospital admissions and death.
Current dietary recommendations for frailty prevention primarily focus on protein intake, but experts said it was becoming clear that certain fruits were also helpful for lowering the risk.
Flavonols are found in many foods including green leafy vegetables, blackcurrants, onions, apples, berries, cherries, peaches, soybeans, citrus foods, tea, chocolate, lettuce, peppers, grapes and even wine.
“Higher flavonol intake was associated with lower odds of developing frailty,” said Prof Shivani Sahni of Harvard Medical School.
“Specifically, higher quercetin intake was the flavonoid that had the strongest association with frailty prevention.
“This data suggests that there may be particular subclasses of flavonoids that have the most potential as a dietary strategy for frailty prevention.”
Flavonols help to regulate cellular activity and work as anti-oxidants to fight off free radicals that cause oxidative stress and damage in the body.
The research was based on data from volunteers enrolled in the Framingham Heart Study, which has monitored the health of residents of Framingham, Massachusetts since the 1940s.
A total of 1,701 over-65s took part in the study, which resulted in 13.2 per cent of participants becoming frail by the end of the 12-year project.
Those who had the highest intake of flavonols – particularly quercetin – were found to be the least likely to become frail.
There is mounting evidence that flavonol may also be useful in fighting Alzheimer’s disease, cancer, cardiovascular disease, arthritis, high blood pressure and Type 2 diabetes.
Research by Wageningen University in the Netherlands also found that eating an average-size apple a day would reduce the risk of stroke by between 36 and 45 per cent, because of its quercetin content.
A study from the University of Reading found that eating two apples per day lowered levels of “bad” cholesterol by almost 4 per cent.
“There may be some validity to the old saying, an apple a day keeps the doctor, or frailty, away,” researchers concluded in the study published in the American Journal of Clinical Nutrition.