Modification by food of the calcium absorbability and physicochemical effects of calcium citrate.
The food-calcium (Ca) interaction was examined in 12 healthy women (mean age 38 years) maintained on a constant metabolic diet. They underwent three phases of study, comprised of control (no Ca), Ca citrate (1 g Ca/day) during meals, and Ca citrate separately from meals. Each phase was 7 days in length and two 24-hour urine samples were collected on days 6 and 7. The rise from the control phase in urinary Ca was slightly more prominent when Ca citrate was given with meals than without (68 and 62%, respectively). The fall in urinary phosphorus was equivalent at about 25% between Ca citrate phases. The rise in urinary citrate and pH and the decline in urinary ammonium were more prominent when Ca citrate was given with meals; however, the changes were small or nonsignificant. The urinary saturation of Ca oxalate, brushite or monosodium urate did not differ between the two Ca citrate phases. There was a nonsignificant rise in serum iron during Ca citrate phases. The results suggest that: 1) dissolution and absorption of Ca citrate might be slightly greater when given with food than without; 2) that the ability of Ca citrate to attenuate crystallization of stone-forming Ca salts in urine is not modified by food; and 3) that Ca citrate may not impair iron absorption from food.
Wabner
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Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas 75235-8885.
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D000328:Adult; D002118:Calcium / Q000097:blood / Q000378:metabolism* / Q000652:urine; D002951:Citrates / Q000008:administration & dosage / Q000378:metabolism*; D019343:Citric Acid; D005260:Female; D005502:Food; D006801:Humans; D008875:Middle Aged
D002951:Citrates; D019343:Citric Acid; D002118:Calcium