News Release

Individuals vary greatly in their ability to absorb calcium

Peer-Reviewed Publication

American Journal of Clinical Nutrition

Recent clinical and epidemiological studies suggest that the amount of calcium an individual consumes may have an impact on the development of such diseases as osteoporosis, hypertension and colon cancer. Yet the health benefits of taking calcium depend on each individual's ability to absorb it. In a study published in The American Journal of Clinical Nutrition, Wolf et al. examined interindividual variations in calcium absorption in a group of 142 pre- or perimenopausal healthy women ages 45 to 53. The data were analyzed in relation to several dietary, lifestyle, physiological and genetic factors. Independent predictors of calcium absorption included dietary fat, fiber, alcohol intake and serum concentrations of vitamin D. In particular, the amount of dietary fat consumed in relation to dietary fiber appeared to have an important role in determining the differences in calcium absorption.

The subjects were recruited from the Women's Healthy Lifestyle Project (WHLP), a clinical trial in which half of the subjects were enrolled in an intervention program of a low-fat, high fiber diet designed to modulate cardiovascular risk factors. At 18- or 30-month follow-up appointments, calcium absorption rates ranged from 17% to 58%, and averaged 35%. Using questionnaires, the authors gathered data on eight different dietary and lifestyle factors, including use of calcium supplements, total dietary energy, physical activity, alcohol consumption, caffeine consumption, cigarette use, and symptoms of constipation. Blood concentrations of calcium, parathyroid hormone, and vitamin D were also measured, and genotypes for the vitamin D receptor were determined.

Women with the lowest -fat diets had 19% lower fractional calcium absorption than women with the highest-fat diets. Indeed, the women who had been randomly assigned to the "low-fat diet" intervention group as part of the WHLP study had significantly lower mean fractional calcium absorption values than did the women assigned to the group without any dietary intervention. The authors propose that fat may increase calcium absorption by slowing its transit time through the intestines and allowing longer contact with their absorptive surface. There was a modest but significant decline in the efficiency of calcium absorption among the subjects who were moderate drinkers. The authors suggest that consideration should be given to evaluating individual calcium absorption performance before making calcium intake recommendations. The current "heart-healthy" low-fat, high-fiber diet could affect calcium absorption and hence the development of a number of chronic disorders in which calcium may have a protective role.

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Wolf, Randi L et al. Factors associated with calcium absorption efficiency in pre- and perimenopausal women. Am J Clin Nut 2000;71:466-71.

For more information please contact Dr. Randi Wolf at wolf@exchange.tc.columbia.edu

This media release is provided by The American Society for Clinical Nutrition, to provide current information on nutrition-related research. This information should not be construed as medical advice. If you have a medical concern, consult your doctor.

To see the complete text of this article, please go to: http://www.faseb.org/ascn/temp/ajcn/August/466-471-wolf1.pdf


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