QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by O'Brien, K. O. Articles by Yergey, A. L. Search for Related Content PubMed PubMed Citation Articles by O'Brien, K. O. Articles by Yergey, A. L.

High Fiber Diets Slow Bone Turnover in Young Men but Have No Effect on Efficiency of Intestinal Calcium Absorption^1,2,

Kimberly O. O'Brien⁴, Lindsay H. Allen, Paula Quatromoni^*, Mei-Ling Siu-Caldera, Nancy E. Vieira, Alberto Perez^*, Michael F. Holick^* and Alfred L. Yergey

Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269-4017 ^* General Clinical Research Center, Boston University School of Medicine, Boston, MA 02118 Section on Metabolic Analysis and Mass Spectrometry, National Institutes of Health, Bethesda, MD 20892

Dietary fiber reduces the absorption of dietary calcium from a meal, but its impact on calcium kinetics is unknown. We therefore evaluated the effects of a high fiber diet on calcium balance and kinetics and on calcium-regulating hormones. Seven young men each participated in two 23-d experiments. In the low fiber period the controlled diet provided 6.5 g fiber/d and 530 mg calcium/d. In the high fiber period fiber was increased to 31.3 g/d and calcium to 586 mg/d by substituting high fiber cereal. Measured between d 7 and 12 of each period, the high fiber diet significantly lowered the apparent absorption of calcium (from 60.6 ± 23.8% to 37.1 ± 26.5%) and reduced calcium balance, although balance remained positive overall. Fiber had no effect on serum total or ultrafiltrable calcium, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D or parathyroid hormone concentrations measured on d 1, 7, 12 and 20. Calcium kinetics was studied between d 17 and 23 by administering oral ⁴⁴Ca and intravenous ⁴²Ca to fasting subjects. Fractional absorption of calcium in the fasting state was unaffected by fiber. However, during the high fiber period, subjects had significantly lower bone accretion, resorption and turnover rates, and calcium flow to bone from the exchangeable pool than during the low fiber period. We conclude that the fiber-induced reduction in calcium absorption slowed down bone calcium turnover but did not increase the efficiency of intestinal absorption.

KEY WORDS: • calcium • kinetics • dietary fiber • vitamin D • humans

¹ Funded by the National Dairy Board in cooperation with the National Dairy Council, the Storrs Agricultural Experiment Station, and NIHMOIRR0533.

² Scientific Contribution no. 1482, Storrs Agricultural Experiment Station, Storrs, CT.

³ The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 USC section 1734 solely to indicate this fact.

⁴ To whom correspondence should be addressed at: National Institutes of Health, 9000 Rockville Pike, Building 10, Room 6C101, Bethesda, MD 20892.

Manuscript received 15 April 1993. Initial review completed 24 May 1993. Revision accepted 20 July 1993.