In a calcium and bone study, researchers explained that about 35 percent of adult bone mass forms during puberty. Doctors recruited 96 girls, average age 12, who did not get enough calcium from diet, to take 792 mg of calcium citrate malate dissolved in a fruit drink per day or a placebo. After 18 months, girls who had taken calcium had significantly greater bone mineral density (BMD) throughout their entire skeleton compared to placebo. Two years later, after stopping calcium supplements, the girls who had taken calcium had lost the BMD benefit.
In a review of bone mineral content (BMC) studies covering more than 3,800 children, scientists noted that kids with the lowest calcium levels benefited the most from taking calcium supplements and dairy products with calcium and vitamin D. They also noted that 70 percent of boys and 90 percent of girls do not get enough calcium to maintain strong bones.
In a bone fracture risk study, 670 men and 260 women, average age 61 and generally healthy, took 1,200 mg of calcium per day or a placebo. After four years, those who had taken calcium were 72 percent less likely to have had a bone fracture compared to placebo. Participants then stopped taking calcium. Doctors followed up for another six years and found that, without calcium, the fracture risk benefit disappeared.
In a BMD study, investigators measured blood levels of folate in 117 healthy post-menopausal women who were not taking calcium or vitamin D supplements and found that women who had the highest levels of folate retained more BMD over five years than women with low folate levels. Folate is a form of folic acid.
Beginning in 2010, the U.S. Food and Drug Administration will allow food manufacturers to claim that vitamin D is good for bone health and reduces risk for bone disease (osteoporosis), adding to the current bone health claim for calcium.