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Title: THE EFFECT OF CALCIUM SUPPLEMENTS AND STAGE OF LACTATION ON THE EFFICIENCY OF ABSORPTION OF CALCIUM BY LACTATING WOMEN ACCUSTOMED TO LOW CALCIUM INTAKES

Author
item FAIRWEATHER-TAIT, SUSAN - INST OF FOOD RES NORWICH
item PRENTICE, ANN - MRC DUNN NUTRITION UNIT
item HEUMANN, KLAUS G - UNIVERSITY OF REGENSBURG
item JARJOU, LANDING - MRC DUNN NUTRITION UNIT
item STIRLING, DOROTHY - MRC DUNN NUTRITION UNIT
item WHARF, S - INST OF FOOD RES NORWICH
item Turnlund, Judith

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: There is some disagreement as to how much calcium is required during lactation, which is mainly due to the lack of information on the nature of adaptive responses to increased physiological demands. Dietary recommendations for calcium in lactating women differ between countries, but most authorities currently recommend about 30 mmol (1200 mg) per day (e.g. FAO/WHO 25-30, USA 30 and UK 31.25 mmol/day), a value that is easily achievable in countries that consume dairy products. However, in non-dairying countries like Gambia, where prolonged lactation is the usual practice, the effects of a habitually low dietary calcium intake on mothers and infants is not known. A study was set up to determine whether lactating Gambian mothers would benefit by an increase in calcium intake to a value close to that recommended by FAO/WHO for breast-feeding women. Absorption in the UK mothers was significantly lower than Gambian women. At 12 months lactation the mean efficiency of calcium absorption of the Gambian mothers declined. The results suggest Gambian women adapted to lower calcium intake by increasing absorption.

Technical Abstract: The effect of calcium intake on the efficiency of calcium absorption from 100 ml cow's milk was measured in lactating Gambian mothers habituated to a low calcium diet (mean intake 7.08 mmol (283 mg)/d), and compared with UK lactating mothers on high calcium diets (mean intake 28 mmol (1120mg)/d) using a double stable isotope technique (oral **44Ca and i.v. **42Ca). In a double-blind trial, starting 9 days post-partum, Gambian mothers were given a calcium supplement (17.85 mmol (714 mg)/d) or placebo for 12 months. At 3 months post-partum, the unsupplemented Gambian mothers absorbed 52.3 +/- 3.1%, the supplemented mothers 48.8 +/- 2.8%, and the UK mothers 32.2 +/- 3.8% of the isotopically-enriched calcium added to milk. Absorption in the UK mothers was significantly lower than both Gambian groups (p<0.01). At 12 months lactation the mean efficiency of calcium absorption of the combined unsupplemented and supplemented Gambian mothers fell from 47.2 (4.8)% to 42.9 (3.7)% (p<0.05)