Fruit and veg may considerably boost bone health as part of a daily diet, according to a new US study.

Increasing the alkali content of the diet by eating fresh produce may reduce calcium excretion and boost bone health, a study published in the Journal of Clinical Endocrinology & Metabolism stated.

Dr Bess Dawson-Hughes of Tufts University in Boston said: "When it comes to dietary concerns regarding bone health, calcium and vitamin D have received the most attention, but there is increasing evidence that the acid/base balance of the diet is also important.”

Bone health is becoming a major segment of the supplements and functional foods market, as ageing populations and the additional strain from obesity swell the numbers affected by osteoporosis.

The lifetime risk for a woman to have an osteoporotic fracture is 30-40 per cent and in men the risk is about 13 per cent.

As adults age they become less able to excrete the acid produced via dietary metabolism, explained Dawson-Hughes. Reacting to the increasing acid levels, the body counters this by bone resorption, a process by which bones are broken down, releasing minerals such as calcium, phosphates, and alkaline salts into the blood. Bone resorption weakens the bones and increases the risk of fracture.

Tufts researchers, in collaboration with scientists from Northeastern University in Boston, recruited 171 men and women aged 50 or older and randomly assigned them to receive supplements of potassium bicarbonate, sodium bicarbonate, potassium chloride or placebo for three months.

“When fruits and vegetables are metabolized they add bicarbonate, an alkaline compound, to the body," said Dawson-Hughes.

"Our study found that bicarbonate had a favourable affect on bone resorption and calcium excretion. This suggests that increasing the alkali content of the diet may attenuate bone loss in healthy older adults."