It’s another of those 21st-century epidemics that we keep hearing about, but the scale of this one is truly worrying. Osteoporosis affects one woman in three over the age of 50, and one in 12 men. That compares to one in nine women affected by breast cancer, which has a much higher public profile.

Yet like cancer, osteoporosis can kill. According to some estimates it results in more women dying every year than ovarian, cervical and uterine cancers combined. The fractures caused by osteoporosis, a bone-weakening disease caused when the honeycomb mesh that makes the bone becomes thin and fragile, can be traumatic. Because it is rarely picked up in its early stages, fractures can occur out of the blue; sometimes a cough can cause a rib fracture. One study showed that one woman in five dies within a year of a hip fracture because of complications such as infections.

And the real worry is for the future. According to many experts, a whole generation is in danger of having low bone density because of poor diet and lack of exercise. A recent study in the Archives of Pediatric and Adolescent Medicine suggested that girls as young as 16 are suffering bone fractures because they are drinking so many fizzy drinks; the phosphoric acid may be leaching the bones of calcium, which is essential for keeping the mesh strong.

But a new book is suggesting that all this is unnecessary; that osteoporosis is not only preventable but naturally treatable. And it doesn’t revolve around taking drugs or having hormone replacement therapy, but around eating the right foods. And according to its author, the nutritionist Dr Marilyn Glenville, it’s not simply a question of drinking more milk or eating lots of high-calcium foods or supplements, the conventional advice offered by the nation’s doctors.

In fact, she says, our problem is that we eat too much animal protein such as butter, cheese and fish, the sorts of food traditionally recommended by doctors as good sources of calcium. This is naturally acidic, she says, and actually causes calcium to be lost from the bones. Fruit and vegetables, on the other hand, have an alkaline effect which promotes bone health.

So Glenville advocates an approach that concentrates not on maximising calcium intake, but on minimising the loss of calcium and other minerals that are already contributing to bone health: “One of calcium’s roles in the body is to act as a neutraliser,” she says. “When you eat too much acidic food your body calls up the alkaline calcium reserves from your bones to counteract the acidity. Therefore, if your diet is highly acidic — high in meat, for instance — it could cause a leaching effect on your bones. So even if you are eating a calcium-rich diet and taking calcium supplements, you could be losing more calcium than you are gaining. Because fruit and vegetables are alkaline, they do not force the skeleton to release calcium, and also magnesium, to buffer the effects of excess acid.”

If you think it sounds like science made up on the hoof, you may be surprised by the fact that Glenville, a Fellow of the Royal Society of Medicine, is one of the more respected nutritional therapists in the UK. She has packed her book with references to credible academic research backing up the acid-alkali theory, and the importance of a broad dietary approach rather than one based largely on calcium supplementation.

The National Osteoporosis Society (www.nos.org.uk), which generally advocates a balanced diet but one containing high-calcium foods from animal and vegetable sources, acknowledges that there is something in what Glenville says. But it is keeping all options open. “There have been small studies showing that there is more calcium excreted in the urine with a high protein diet,” says Jackie Parrington, the society’s deputy chief executive. “What they haven’ t established is a direct link between this and broken bones through osteoporosis. There’s no evidence that you should avoid all animal protein; milk in particular has value because it has a neutral pH. Just don’t eat lots of acidic food like red meat and hard cheese.”

Glenville is puzzled that such a cautious approach has become the medical orthodoxy when there is evidence that the minerals we lose are the problem, rather than not taking enough in. She cites one study of older women, conducted over seven years, which found that those who ate a high animal-protein diet had more bone loss and a greater risk of hip fractures than women on a lower animal-protein intake. All women will benefit from an alkaline diet to protect their bones, she says, but especially menopausal women, who are at high risk of osteoporosis because of hormonal changes.

She believes her approach can also reverse osteoporosis by giving the body a chance to replenish the bones with calcium and other vital minerals: “If you just try to supplement your calcium, without addressing calcium loss, it’s like taking two steps forward and one back.”

The dietary changes she recommends aren’t revolutionary: “It’s a generally healthier way to eat. Reduce the size of your portion of animal protein and boost the vegetable part of the meal. Aim for at least one portion daily of leafy green vegetables such as broccoli, cabbage and kale, but not spinach as it blocks calcium absorption.”

Osteoporosis: the Silent Epidemic, by Dr Marilyn Glenville, is published by Kyle Cathie on May 10, £10.99 — available at £8.79, plus p&p, from Times Books First, 0870 1608080, or www.timesonline.co.uk/booksfirstbuy

Eating habits

Eat more apples, apricots, aubergines, bananas, carrots, cauliflower, courgettes, raisins, tomatoes.

Eat less bread, cheddar, cheese, chicken, egg noodles, spaghetti, oats, parmesan cheese, rump steak, trout.

Osteoporosis outline

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