Magnesium may be as important to kids' bone health as calcium

Parents are advised to make sure their children drink milk and eat other calcium-rich foods to build strong bones. Soon, they also may be urged to make sure their kids eat salmon, almonds and other foods high in magnesium — another nutrient that may play an important role in bone health, according to a study to be presented Sunday, May 5, at the Pediatric Academic Societies (PAS) annual meeting in Washington, DC.

"Lots of nutrients are key for children to have healthy bones. One of these appears to be magnesium," said lead author Steven A. Abrams MD, FAAP, professor of pediatrics at Baylor College of Medicine in Houston. "Calcium is important, but, except for those children and adolescents with very low intakes, may not be more important than magnesium."

While it is known that magnesium is important for bone health in adults, few studies have looked at whether magnesium intake and absorption are related to bone mineral content in young children. This study aimed to fill that gap.

Researchers recruited 63 healthy children ages 4 to 8 years old who were not taking any multivitamins or minerals to participate in the study. Children were hospitalized overnight twice so their calcium and magnesium levels could be measured.

Participants filled out food diaries prior to hospitalization. All foods and beverages served during their hospital stay contained the same amount of calcium and magnesium they consumed in a typical day based on the diaries. Foods and beverages were weighed before and after each meal to determine how much calcium and magnesium the subjects actually consumed. In addition, parents were given scales to weigh their child's food for three days at home after the first inpatient stay and for three days at home prior to the second inpatient stay so that dietary intake of calcium and magnesium could be calculated accurately.

While hospitalized, children's levels of calcium and magnesium were measured using a technique that involved giving them non-radioactive forms of magnesium and calcium, called stable isotopes, intravenously and orally. Urine was collected for 72 hours. By measuring the stable isotopes in the urine, the researchers could determine how much calcium and magnesium were absorbed into the body. Bone mineral content and density were measured using total body dual-energy X-ray absorptiometry.

Typically, when parents think about their children’s health, they don’t think about their bones. But building healthy bones by adopting healthy nutritional and lifestyle habits in childhood is important to help prevent osteoporosis and fractures later in life.

Osteoporosis, the disease that causes bones to become less dense and more prone to fractures, has been called “a pediatric disease with geriatric consequences,” because the bone mass attained in childhood and adolescence is an important determinant of lifelong skeletal health. The health habits your kids are forming now can make, or literally break, their bones as they age.