Vitamin pills may not help you ward off brittle bone disease and could raise risk of kidney problems

Millions of Britons who take vitamin D and calcium pills to prevent bone thinning may be wasting their time, scientists warn today.

There is little evidence the supplements prevent fractures – and they may even cause harm through kidney complications and strokes.

Researchers say the benefits of the pills may have been hugely overplayed by their manufacturers. Around a third of men and just under half of women take supplements including vitamin D and calcium, and many get them on prescription from their GP.

The pills are thought to prevent osteoporosis, the bone-thinning condition that occurs in middle age which is particularly common in women after the menopause.

Calcium is a naturally occurring mineral which helps strengthen the bones while vitamin D is thought to help the body absorb it. But several major studies published in the last decade have found no evidence that adults taking these pills are any less likely to suffer bone fractures.

Researchers say most get enough calcium in their diets anyway, mainly from dairy products, while vitamin D may not actually help our bodies absorb it. In an editorial in the BMJ Open online journal, academics from New Zealand also highlight evidence that supplements increase the risk of strokes, kidney stones and heart attacks.

They say over-65s ‘should not have been recommended’ to take daily vitamin D supplements to prevent osteoporosis under Government guidelines in the UK and elsewhere.

The vitamins supplements market is worth around £400million a year in the UK, and the NHS spends £80million a year on prescriptions for vitamin D alone.

Professor Andrew Grey and Professor Mark Bolland, of the Department of Medicine in the University of Auckland, point out that evidence has emerged since 2002 that such supplements ‘do not reduce the risk of fracture and may result in harm’.

They also say the manufacturers of supplements help fund organisations such as the International Osteoporosis Foundation, which produce guidelines on who should take vitamin D and calcium.

A separate BMJ Open article by researchers at Queen Mary, University of London, calls for the public to be made aware of the ‘lack of evidence’ that vitamin D does them any good. They found the number of prescriptions for vitamin D in one East London health trust had increased ten-fold in the past five years.

Around three million adults in Britain have osteoporosis, and women are four times more at risk than men. The Government recommends that all adults over 65 take a daily vitamin D supplement to help prevent the disease, as well as anyone else who spends large amounts of time indoors.

The main source of vitamin D is a chemical reaction which occurs when the Sun’s rays are absorbed by our skin, although small amounts are found in eggs, oily fish and some breakfast cereals.

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