Calcium Supplementation Can Reverse Bone Loss
MA, 21 March 2002
new study by Tufts University researchers reports that elderly Americans
who are on high protein diets and have adequate calcium intake can
reverse bone loss usually associated with high protein diets.
given 500 mg calcium plus vitamin D or dummy placebo
a randomized, placebo-controlled study, published in the April issue
of the American Journal of Clinical Nutrition, researchers
from the Jean Mayer USDA Human Nutrition Research Center on Aging
at Tufts University (HNRCA) gave 342 healthy men and women over
age 65 either daily calcium (500 milligrams) and vitamin D supplements,
or a dummy pill for three years. During the study, the researchers
reviewed the volunteers' diets (specifically their calcium and protein
intake) and bone mass density.
effects on bone mass density
results show that the supplemented adults who ate a diet high in
protein displayed significant positive effects on their bone mass
density. On the other hand, for the volunteers who took the placebo,
calcium levels absorbed into their bloodstream were reduced as they
consumed more protein.
results suggest that a higher calcium intake is going to be protective
against any adverse effects of protein on bone, and may allow protein
to have a positive effect," says Bess Dawson-Hughes, M.D., lead
author of the study, and senior scientist and chief, Calcium and
Bone Metabolism Laboratory, Jean Mayer USDA HNRCA at Tufts University.
the recommended dietary allowance (RDA) for calcium
recommended dietary allowance (RDA) for calcium is 1,200 milligrams,
which can easily be achieved by consuming one calcium supplement
(500 mg), one cup of fat-free milk, one 8-oz. serving of yogurt,
and a 1-oz. slice of cheese.
average protein intake by the volunteers in the study was 79 grams
per day (g/d), and the adults who ate the most protein averaged
96 g/d. The recommended protein intake for a healthy person is between
40-60g/d. Elderly people may be on a high protein diet to increase
their caloric intake, help wound healing and maintain muscle mass.
Additionally, like millions of Americans, they may desire to lose
weight using a high protein, low carbohydrate plan. The type of
protein consumed -- plant or animal -- did not make a difference
in the effect on bone mass density, rather it was the amount of
protein in the diet.
can aid in calcium absorption
researchers note that when there is sufficient calcium in the diet
(through food and/or supplement), protein may aid in calcium absorption,
as reported here. Previous studies of this kind have reported contradictory
results. One study showed a low-protein diet was associated with
a greater rate of bone loss, whereas another study associated a
high-protein diet with a greater rate of bone loss. Scientists are
not yet able to agree on the effect of protein in the diet on bone,
but they have concurred on the negative impact of low-calcium diets
on bone density.
results help us to better understand the mechanics behind calcium
and vitamin D supplementation and their effect on bone mass density,"
explains Dawson-Hughes. "This study is a significant confirmation
that adequate calcium in the diet is crucial. This report, however,
also shows that there is much more research needed in this area."
the research center at Tufts University
Gerald J. and Dorothy R. Friedman School of Nutrition Science and
Policy at Tufts University is the only independent school of nutrition
in North America. The school's eight centers, which focus on questions
relating to famine, hunger, poverty, and communications, are renowned
for the application of scientific research to national and international
policy. For two decades, the Jean Mayer USDA Human Nutrition Research
Center on Aging at Tufts University has studied the relationship
between good nutrition and good health in aging populations. Tufts
research scientists work with federal agencies to establish the
USDA Dietary Guidelines, the Dietary Reference Intakes, and other
significant public policies.
speak with the Tufts researchers about the implications of this
important study on protein and calcium, contact Randi Konikoff at
617-636-3736 or email firstname.lastname@example.org.
University, via PR Newswire, 21 March 2002.