Protein Saves Bone in Elders
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ARS News Service
Agricultural Research Service, USDA
April 6, 2001
Judy McBride, (301) 504-1628, jmcbride@ars.usda.gov
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It's no secret that people need ample calcium and vitamin D to maintain
strong bones, even in their twilight years. Now, a study suggests that
protein intake may be important in reducing bone loss in elders.
The 70- to 90-year-old men and women with the highest protein intakes lost
significantly less bone over a four-year period than those who consumed half
or less the protein. Animal protein, as well as overall protein intake, was
associated with preserving bone.
The study was conducted by researchers with the Hebrew Rehabilitation Center
for Aged, Research and Training Institute; Boston University; and the Jean
Mayer USDA Human Nutrition Research Center on Aging, all in Boston, Mass.
Lead author Marian T. Hannan at the Hebrew center collaborated with
Katherine L. Tucker at the USDA center and others. The USDA center is funded
by the department's chief scientific research agency, the Agricultural
Research Service.
The findings run counter to studies of younger people that found diets high
in protein, especially animal protein, cause the body to excrete more
calcium. However, they confirm several other large population studies
showing protein to have a positive overall effect on bone, according to
Hannan.
With data from 615 participants in the Framingham (Mass.) Osteoporosis
Study, the researchers examined the relationship between their protein
intakes in 1988-89 and changes in bone mineral density four years later.
They accounted for all factors known to increase risk of bone loss.
Participants who reported the lowest daily protein intakes--roughly
equivalent to half a chicken breast--had lost significantly more bone in the
hip and spine four years later than those with the highest
intakes--equivalent to about nine ounces of steak and a cup of tuna salad.
The group with the next lowest intake--equivalent to about two cups of
cottage cheese-- also lost significantly more bone than the highest-intake
group, but only at the hip. People can search the USDA food composition
tables for the protein content of more than 6,000 foods at:
http://www.nal.usda.gov/fnic/cgi-bin/nut_search.pl
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Scientific contact: Katherine L. Tucker, Jean Mayer USDA Human Nutrition
Research Center on Aging, Boston, Mass., phone (617) 556-3351, fax (617)
556-3344, tucker@hnrc.tufts.edu.
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