Here’s another reason why kids should eat their broccoli - fruits and vegetables build strong bones, a new study shows.

Boys who ate the most fruit and vegetables showed the greatest accumulation of mineral in their bones throughout childhood and adolescence, Dr. Hassanali Vatanparast of the University of Saskatchewan in Saskatoon and colleagues found. Higher bone mineral content translates to denser, stronger bones.

Boys who exercised more and consumed more calcium also developed stronger bones over the course of the study.

Vatanparast points out that while adolescence is the prime time for building bone mass, kids frequently don’t take in enough calcium for optimum bone strength. Failing to form strong bones in youth boosts the risk of problems later on, such as the brittle bone disease osteoporosis.

He and his team followed 85 boys and 67 girls aged 8 to 20 years over a seven-year period. Study participants were surveyed on their diet and their height and weight were measured every six months, while their total bone mineral content was tested every year with a technique known as dual-energy X-ray absorptiometry. The findings are published in the American Journal of Clinical Nutritional.

While most of the study participants consumed enough dairy products, the researchers found, most did not eat recommended amounts of fruits and vegetables.

The researchers found that boys who consumed 10 servings of fruit and vegetables a day would wind up accumulating 48.6 grams more mineral content in their bones than boys who ate just a single serving.

The nutritional quality of the North American diet has worsened in the past three decades, Vatanparast noted, especially among young people, while the popularity of sugar-loaded beverages like sodas and fruit drinks means they’re also drinking less milk, which is the main source of calcium in young people’s diets.

While the study found no link between fruit and vegetable consumption and bone density among girls, Dr. Vatanparast points out that other research has found that girls who eat more fruit and vegetables do in fact have denser bones. He said his study might have missed the effect in females because girls, especially teens, are known to underreport their food consumption.

In addition to containing calcium, Vatanparast noted, fruit and vegetables are rich in minerals required to control levels of acid in the body and thus prevent bone loss. Plant foods also contain vitamin K, a nutrient necessary for the formation of bone cells.

“We can say that there is a lifetime beneficial effect of fruit and vegetables on bone mass,” Vatanparast said. These lifetime benefits can extend beyond the skeleton, he added; good dietary habits in youth tend to be maintained as people get older, and can help protect against obesity and chronic illness linked to excess weight such as type II diabetes and heart disease.

SOURCE: American Journal of Clinical Nutritional, September 2005.