Giving children foods fortified¹ with calcium² to help build up their bones may be a waste of time, say experts.

The mineral is added to many breakfast cereals, snack bars and drinks as manufacturers woo the parental³ market.

But scientists have found that such products do not produce significantly stronger bones, nor do they reduce the chance of a child suffering fractures.

It is thought that calcium artificially added to food passes through the body too quickly to be properly absorbed and therefore fails to perform the same functions as foods which are naturally rich in calcium, such as milk, cheese and leafy green vegetables.

It is now built into such things as Kellogg's Coco Pops, breakfast bars such as the Frosties Cereal and Milk bar, some Tropicana orange juices and even a calcium-enriched water called Danone Activ. The theory is that if children build strong bones it will protect them better against problems such as osteoporosis in later life. But the research casts doubt on the usefulness of such products. Experts analysed 19 studies where children aged⁴ between three and 19 were given extra calcium in their diet in this way. They then measured the impact by measuring their bone mineral density⁵ and mineral content.

The team found few significant increases in bone mass and none in the two bones which are most vulnerable to fracture - the lower spine⁶ and upper part of the thigh⁷. A small impact was noted⁸ in bone density in the arm, but it cut the risk of fracture by just 0.2 per cent, according to the report published in the Cochrane Library. The influential⁹ publication is produced by the international health research organisation¹⁰, the Cochrane Collaboration¹¹.

Lead researcher Professor Frank R Greer, of the University of Wisconsin, said the findings for children echo those seen in adult studies. "You can get some short-term improvements but as soon as you stop the supplements it goes right back to where it was," he said. 　　为了让孩子的骨骼健康成长，给他们吃添加了钙质的食品是众多家长们的选择。而美国有关专家日前表示，这种做法可能纯粹是在浪费时间。