Effect of age on intestinal calcium absorption and adaptation to dietary calcium.

Armbrecht, H. J.; Zenser, Terry V.; Bruns, M E; Davis, Bernard B.

doi:10.1152/ajpendo.1979.236.6.e769

Cited by 52 publications

(43 citation statements)

References 17 publications

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“…absorption expressed as percent of intake), whereas high intake is associated with low fractional absorption. This adaptive response has been demonstrated in various animal species (4,(25)(26)(27)(28)(29)(30)(31)(32)(33)(34) as well as in adult man (24, 35, 361, but not in infants. It involves the active, saturable component of calcium absorption (27,32) and is vitamin D dependent (25,37).…”

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confidence: 90%

Effect of Dietary Calcium on Metabolic Balance of Normal Infants

et al. 1985

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ABSTRACT. Metabolic balance studies were performed with six normal infants fed in a balanced cross-over design three formulas differing only in calcium concentration: 389, 659, and 1024 mgjliter, Absorption of phosplrorus was significantly affected by increasing calcium intake decreasing from 68 to 63 to 52% of intake. However, since urinary excretion of phosphorus also decreased, there was no significant effect on retention of phosphorus. Absorption of fat was slightly (but significantly) depressed by calcium, decreasing from 97.5 to 95.5 to 92.1% as calcium intake increased. 'The level of dietary calcium bad no significant effect on absorption or retention of nitrogen, magnesium, copper, and zinc. One of the subjects had consistently lower absorption of calcium and fat than the other subjects, suggesting an absorptive defect. The decrease in fractional absorption of calcium (57 to 47 to 39% of intake) with increasing intake of calcium is compatible with adaptive regulation. On the other hand, the observation that absorbed calcium (mg/kg/day) was linearly related to intake of salcium with a slope of 0.373 suggests an alternative explanation: constant passive, concentration-dependent (slope), and constant active (y-intercept) transport of calcium over the range of calcium intakes. Thus, the findings are explainable in more than one way and do not necessarily demonstrate regulatory changes. (1)(2)(3)(4) and in human subjects (5-71, including the premature infant (8). High dietary intake of calcium also has been shown to depress absorption of fat in animals (9, 101, children ( I 1) and infants, both preterm (8, 12) and t e r n (13, 14). A negative effect of high calcium intake on absorption of zinc has been demonstrated in animal studies (1 5-18), but balance studies in adult humans have not confirmed this effect (19)(20)(21)(22). Absorption of copper does not seem to be influenced by dietary calcium

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confidence: 90%

Effect of Dietary Calcium on Metabolic Balance of Normal Infants

et al. 1985

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“…The second purpose of the study was to compare the conver- sion of 25-OH-D3 to 1,25-(OH)2-D3 in the mammalian kidney of young and adult rats. The rat was used because the intestinal absorption of calcium (8), the plasma levels of 1,25-(OH)2-D3 (9), and the intestinal levels of the vitamin D-stimulated calcium-binding protein (CaBP) (8,10) all decrease with age in the rat. The results of these experiments indicated that there was a marked decrease in the intestinal response of the vitamin D-deficient adult rat to 25-OH-D3.…”

Section: Introductionmentioning

confidence: 99%

Effect of age on the conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 by kidney of rat.

Armbrecht¹,

Zenser²,

Davis³

1980

J. Clin. Invest.

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109

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A B S T R A C T The decreased absorption ofcalcium by the small intestine of the adult may reflect changes in vitamin D metabolism with age. The purpose of this study was to compare the capacity of young (1.5 mo of age) and adult (12-mo In the adult rat, only 2.1±0.6% of the plasma radioactivity was in the form of 1,25-dihydroxyvitamin D3 after 24 h compared with 20.8±3.0% in the young. The conversion oftritiated 25-hydroxyvitamin D3 to its products was also measured directly in isolated slices of renal cortex. 1,25-Dihydroxyvitamin D3 production by adult renal slices was found to be less than one-tenth that of slices from the young. These results indicate that there is a marked decrease in the capacity of the vitamin D-deficient adult rat to convert 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3. This is probably due to the decreased capa.city of the adult kidney to 1-hydroxylate 25-hydroxyvitamin D3. These studies also demonstrate the usefulness of renal slices in measuring changes in the ren l conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 in the mammal.

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“…This decrease may correspond to a decrease in the organism's requirement with age. Armbrecht et al (27) indicated that the active transport component of the absorption mechanism declined with age. The saturable process developed rapidly beginning at 18d of age and peaked at 20 to 40d (28).…”

Section: Discussionmentioning

confidence: 99%

Bioavailability of Milk Micellar Calcium Phosphate-Phosphopeptide Complex in Rats.

Toba

Kato

Takada

et al. 1999

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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SummaryWe evaluated the bioavailability of two types of calcium from milk in two experiments. One was a micellar calcium phosphate phosphopeptide (MCP-PP) complex in which the chemical form was similar to the original form of milk, and the other was a commercial whey calcium in which the chemical form was different from that of milk. In experiment 1, the calcium absorption, bone mineral density, and bone strength were examined when growing female rats were fed either MCP-PP complex or whey calcium as the sole source of calcium for 46d. In experiment 2, the calcium solubility in the small intestine was measured when female rats were meal-fed either MCP-PP complex or whey calcium. The apparent calcium absorption rate in both groups decreased time-dependently during the experimental period, but the time-dependent change in the apparent calcium absorption rate was statistically different. It decreased more slowly in rats fed the MCP-PP diet than in rats fed the whey calcium diet. The bone mineral density of the femur in rats fed the MCP-PP diet was significantly higher than that of the rats fed the whey calcium diet. The bone strength (breaking force and energy) of the femur in rats fed the MCP-PP diet was higher than in the rats fed the whey calcium diet. The amount of soluble calcium in the small intestinal contents in rats at 2.5h after ingestion of the MCP-PP diet was approximately three times higher than that found in rats fed the whey calcium diet. These results indicate that the calcium bioavailability of MCP-PP complex is higher than that of whey calcium, and this difference is due in part to the solubility in the intestine.

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Effect of age on intestinal calcium absorption and adaptation to dietary calcium.

Cited by 52 publications

References 17 publications

Effect of Dietary Calcium on Metabolic Balance of Normal Infants

Effect of Dietary Calcium on Metabolic Balance of Normal Infants

Effect of age on the conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 by kidney of rat.

Bioavailability of Milk Micellar Calcium Phosphate-Phosphopeptide Complex in Rats.

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