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A few years ago, researchers at the
Jean Mayer USDA Human Nutrition Research Center on Aging, at Tufts University
in Boston, Massachusetts, showed that healthy men and women over 65 could
benefit from taking calcium and vitamin D supplements. Half of the study
volunteers took an extra 500 milligrams of calcium and 700 international units
(IU) of vitamin D daily for 3 years. These volunteers either gained or retained
bone in the spine, hip, and throughout the body, compared to those who got a
placebo.
But would that benefit last if the supplements were discontinued? That's what
study leader Bess Dawson-Hughes and colleagues set out to learn. And 295 of the
original 389 volunteers agreed to help her. They no longer took calcium and
vitamin D provided by the study—although, for ethical reasons, they were
allowed to take their own supplements. And they returned to the center once a
year for 2 years for bone measurements and other tests.
Unfortunately, the bone benefits didn't last. By the end of 2 years, "no
supplement-related benefits to spine or hip remained—either in bone
mineral density or bone turnover," says Dawson-Hughes. She noted that the
male volunteers retained some of the benefit to whole-body bone mineral
density, but she can only speculate as to why.
She says the findings have broad implications. Fewer than 1 in 10 U.S. elders
over age 65 meet the current recommendations for calcium and vitamin D. These
amount to a total daily intake of 1,200 milligrams of calcium from food and
supplements and 400 to 600 IU of vitamin D.
Close to two-thirds of the women and about half the men chose to take some
supplemental calcium during the 2-year follow-up. Vitamin D use was a little
lower: About one-half to two-thirds of the women and more than one-third of the
men took some supplemental vitamin D. But the self-selected supplements
"had no impact on the results," says Dawson-Hughes, "perhaps
because the amounts taken were less than half the study levels and perhaps
because use was not regular."
Based on these findings, she and her colleagues concluded that men and women
age 65 and older should try to meet the current recommended calcium and vitamin
D intakes on a continuous basis.—By
Judy McBride,
Agricultural Research Service Information Staff.
Bess Dawson-Hughes is at the
Jean Mayer USDA Human Nutrition Research
Center on Aging at Tufts University, 711 Washington St., Boston, MA 02111;
phone (617) 556-3064, fax (617) 556-3305. |
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