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Keeping bones strong may take more than popping a few pills, according to the latest research.

Scientists from the University of Auckland in Auckland, New Zealand reviewed 23 studies involving 4,082 healthy volunteers with an average age of 59 and report that those who took vitamin D supplements for about two years did not have significantly greater bone density or lower risk of osteoporosis than those who didn’t take them.

That confirms what the U.S. Preventive Services Task Force found earlier this year in its review of the data — that adding 400 IU of vitamin D and 1000 mg of calcium to a healthy diet did not lower the risk of fractures for post menopausal women. Because vitamin D pulls calcium, a building block of bone, from the intestines, doctors have long assumed that urging the elderly to take supplements would help them to maintain healthy levels of vitamin D, which tend wane with age. And data suggesting that about 57% of American adults are deficient in the vitamin only gave the advice more urgency.

But all of that additional D doesn’t seem to be making bones any stronger, say the researchers, who published their findings in the Lancet. For healthy individuals, at least, who are not suffering from osteoporosis, adding more vitamin D to what they are getting from their daily diet — or from sunlight, which the skin transforms into active forms of D — isn’t necessary. Recent studies have also suggested that estimates of vitamin D deficiency may have been misleading, since scientists measured different forms of the vitamin in the body. “Our data suggest that targeting low-dose vitamin D supplements only to individuals who are likely to be deficient could free up substantial resources that could be better used elsewhere in health care,” study author Ian Reid said in a statement. To maintain strong bones, for most adults it’s enough t to take in at least 600 IU of vitamin D daily, from foods such as fatty fish and dairy products. and for the elderly to consume around 800 IU of vitamin D a day.