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Dietary calcium does not exacerbate phytate inhibition of zinc absorption by women from conventional diets

Permanent URL:
http://handle.nal.usda.gov/10113/28999
File:
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Abstract:
BACKGROUND: Although calcium inhibits zinc bioavailability in rats, especially from high-phytate diets, the effect of calcium on zinc absorption by humans from practical diets remains unclear. OBJECTIVE: The objective was to test the inhibitory effect of dietary calcium, in Western diets with high and low phytate content, on zinc absorption. DESIGN: Using a 2 x 2 factorial design, zinc absorption was determined in 10 healthy women from 1-d diets with moderate and high calcium contents of [almost equal to]700 and 1800 mg/d and low and high phytate contents of [almost equal to]440 and 1800 mg/d. Absorption was measured by using extrinsically added ⁶⁵Zn and subsequent whole-body scintillation counting. RESULTS: Mean (±SE) fractional zinc absorption was 32.8 ± 2.3% from the moderate-calcium, low-phytate diet; 26.9 ± 2.4% from the moderate-calcium, high-phytate diet; 39.4 ± 2.4% from the high-calcium, low-phytate diet; and 26.2 ± 2.3% from the high-calcium, high-phytate diet. The respective values for absolute zinc absorption were 3.8 ± 0.3, 3.0 ± 0.3, 4.5 ± 0.3, and 3.2 ± 0.3 mg/d. Phytate significantly reduced fractional zinc absorption by [almost equal to]10 percentage points and reduced absolute zinc absorption by 25%, or [almost equal to]1 mg/d. Differences in dietary calcium did not affect zinc absorption, regardless of a high or low dietary phytate content. CONCLUSIONS: In healthy women consuming 1-d menus of ordinary foods (some fortified with calcium), dietary phytate reduces zinc absorption, but calcium does not impair zinc absorption, regardless of whether dietary phytate is low or high.
Author(s):
Hunt, Janet R. , Beiseigel, Jeannemarie M.
Subject(s):
calcium , dietary minerals , phytic acid , zinc , nutrient-nutrient interactions , intestinal absorption , nutrition physiology , women , nutrient availability , foods
Format:
p. 839-843.
Note:
Includes references
Source:
American journal of clinical nutrition AJN 2009 Mar., v. 89, no. 3
Language:
English
Publisher:
American Society for Clinical Nutrition
Year:
2009
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.