Calcium is critical — especially for kids

No one disputes that calcium is essential for building strong bones and teeth. Women need it. Men need it. Children need it. In fact, while the message about osteoporosis prevention and bone strength seems directed at older women, it is even more important to bolster calcium intake during childhood and adolescence, when there is rapid and significant bone growth, than it is when we are older and losing bone mass.

"We're building bone mass between age 9 and 18. Ninety percent of it develops before age 20 and the rest by age 30," says Tamara Swett, clinical nutritionist at The Regional Center for Health at Stamford Hospital in Connecticut. "What you build up then is most important because after that we can't build more bone mass. After 30, we take in calcium just to maintain" the bone strength we have.

That makes it critically important to begin a diet high in calcium as children and continue it throughout our lives.

Unfortunately, national data indicate that most American children older than 8 don't get enough calcium, leaving them at risk for fractures or for developing osteoporosis in adulthood. A recent report by the American Academy of Pediatrics recommended that doctors evaluate children for calcium intake three times during childhood — at ages 2-3, 8-9 and as teens — by asking key questions about diet, milk consumption, the amount of exercise they get and whether there is a family history of osteoporosis.

The report also included recommendations for daily calcium intake at various ages. In 2003, the academy issued guidelines for vitamin D, which is needed to help the body absorb calcium. Those guidelines recommend vitamin D supplements for breast-fed-only babies and older children who don't get adequate amounts of vitamin D, either because they don't drink vitamin-D fortified milk or don't get enough sunlight (without sunscreen). The human body needs 10 to 15 minutes per week of sun exposure to produce adequate vitamin D.

It is not always easy to get children to consume calcium-rich foods. "We've gotten away from the idea of milk with every meal," says Lynda Mezansky, clinical nutrition specialist at The Tully Health Center in Stamford, Conn. One reason is allergy concern. Although many people cannot digest dairy products, which are the best calcium sources, some parents act before there is a problem and give soy formulas to their children, Mezansky says.

Another obstacle is that as children become teenagers, parents don't have the same control over their diets. "Teenagers are trying to keep their weight down, or they don't like the taste of milk. They often stop eating breakfast, so even in families where they like yogurt with fresh fruit and granola as kids, when they get older they're exposed to a whole new level of tastes, and they change," Mezansky says.

This particular problem was addressed in another recent study, published in The Journal of Pediatrics. The study included 2,300 girls who were observed for 10 years beginning at age 9. It showed that beginning at age 11, milk-drinking declines, and by the time girls reach 19, they are drinking three times more soda and 25 percent less milk than they did as children. It also indicated that the girls who drank less milk had less calcium overall in their diets, a fact that may set them up for osteoporosis when they are older.

In general, foods that contain the most concentrated calcium are dairy products such as milk, yogurt, cheese and ice cream. It makes little difference whether the item is full-fat, low-fat or skim, although some low-fat products have added skim milk to replace the fat, so there may be a slight calcium increase. But there are other good calcium sources: beans; tofu; canned salmon (with bones) and sardines (with bones); fresh salmon; almonds; sesame seeds; dried figs; certain vegetables, such as broccoli, kale, bok choy and collards; and some grains, especially fortified cereals.

"If they don't eat dairy products, it's important to use products like calcium-enriched soy milk and calcium-fortified orange juice," Mezansky says.

And if they do but say they're in a hurry, "give them a yogurt or a smoothie," she suggests, or "anything they might accept, like string cheese."