TY - JOUR
T1 - Wheat bran abolishes the inverse relationship between calcium load size and absorption fraction in women
AU - Weaver, Connie M.
AU - Heaney, Robert P.
AU - Teegarden, Dorothy
AU - Hinders, Sharilyn M.
PY - 1996/1
Y1 - 1996/1
N2 - Fractional calcium absorption from varying intakes of calcium carbonate co-ingested with wheat bran, as well as alone, was measured in a randomized crossover study in healthy adult women. The calcium carbonate was intrinsically labeled with 45Ca. Absorption from the carbonate, ingested without bran, showed the expected inverse relationship to the logarithm of ingested load size (slope = -0.1199; not substantially different from the value previously reported for milk). At 0.5 mmol calcium load, fractional absorption averaged 0.769 ± 0.134, whereas at 12.5 mmol load it averaged 0.378 ± 0.069. In contrast, fractional absorption from calcium carbonate co- ingested with 40 g of s cereal product containing 16 g wheat bran, across a calcium load range from 0.5 to 15.5 mmol, was essentially constant (mean for all loads: 0.230 ± 0.069). Thus, the calcium-binding capacity of the bran cereal altered the usual inverse relationship between calcium load and fractional absorption. In vitro calcium binding to the bran cereal was linear over a wide range of calcium levels. This suggests that binding of calcium to one or more components of the bran cereal is sufficient to explain the reduced absorption demonstrated in vivo.
AB - Fractional calcium absorption from varying intakes of calcium carbonate co-ingested with wheat bran, as well as alone, was measured in a randomized crossover study in healthy adult women. The calcium carbonate was intrinsically labeled with 45Ca. Absorption from the carbonate, ingested without bran, showed the expected inverse relationship to the logarithm of ingested load size (slope = -0.1199; not substantially different from the value previously reported for milk). At 0.5 mmol calcium load, fractional absorption averaged 0.769 ± 0.134, whereas at 12.5 mmol load it averaged 0.378 ± 0.069. In contrast, fractional absorption from calcium carbonate co- ingested with 40 g of s cereal product containing 16 g wheat bran, across a calcium load range from 0.5 to 15.5 mmol, was essentially constant (mean for all loads: 0.230 ± 0.069). Thus, the calcium-binding capacity of the bran cereal altered the usual inverse relationship between calcium load and fractional absorption. In vitro calcium binding to the bran cereal was linear over a wide range of calcium levels. This suggests that binding of calcium to one or more components of the bran cereal is sufficient to explain the reduced absorption demonstrated in vivo.
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U2 - 10.1093/jn/126.1.303
DO - 10.1093/jn/126.1.303
M3 - Article
C2 - 8558315
AN - SCOPUS:0030034922
VL - 126
SP - 303
EP - 307
JO - Journal of Nutrition
JF - Journal of Nutrition
SN - 0022-3166
IS - 1
ER -