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Showing papers on "Mineral absorption published in 1987"


Journal ArticleDOI
TL;DR: In this paper, a technical review discusses evidence for undesirable or potentially hazardous effects on mineral and trace element nutriture that may be associated with increased intakes of dietary fiber, concluding that dietary fiber increases in the order of 50-100% in Western countries should not have significant adverse effect on mineral absorption if adequate intakes of protein and of the minerals in question are maintained.

37 citations


Journal ArticleDOI
TL;DR: Two experiments were conducted to determine the effect of increasing dietary K on macromineral bioavailability from a wheat straw-hay diet, and to monitor changes in the rumen that could affect mineral availability.
Abstract: Two experiments were conducted to determine the effect of increasing dietary K on macromineral bioavailability from a wheat straw-hay diet, and to monitor changes in the rumen that could affect mineral availability. In the first experiment, 12 mature wethers were used in a metabolism study to determine the effect of adding potassium chloride (KCl) to a supplement fed with a diet of 55% NH3-treated wheat straw and 45% bromegrass hay. In the second experiment, similar diets were fed to six wethers with ruminal and abomasal cannulae to determine the site of mineral absorption. Dietary K levels were 1, 2 and 3% of the diet dry matter. Increasing K tended to decrease (P less than .06) apparent absorption of Mg. Potassium absorption increased (P less than .01) with increasing dietary K, but retention was not altered. Quadratic effects (P less than .01) of K were observed for Ca and P apparent absorption and retention. Increased K lowered (P less than .05) plasma Mg in Exp. 1 but not in Exp. 2. Ruminal concentrations of K increased (P less than .01), and concentrations of Na decreased (P less than .05), as dietary K increased. Ruminal fermentation was influenced by dietary K level. Molar proportions of acetate in the rumen were increased (P less than .01) by the addition of K to the diet, while molar proportions of butyrate (P less than .01) and valerate (P less than .01) decreased linearly with increasing K. Time X treatment interactions were present for ruminal propionate, butyrate and NH3-N (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

20 citations


Journal ArticleDOI
TL;DR: In this article, enriched stable isotopes were used in nutrition studies of normal, healthy adults to measure zinc, copper, and iron absorption, and the effects of age, pregnancy, and deveral dietary variables were studied.
Abstract: Enriched stable isotopes were used in nutrition studies of normal, healthy adults to measure zinc, copper, and iron absorption. After obtaining baseline values for zinc, copper, and iron absorption from diets adequate in all nutrients, the effects of age, pregnancy, and deveral dietary variables were studied. Stable isotopes of zinc, copper, and iron were incorporated into diets. Complete fecal samples were collected and the unabsorbed isotopes remaining in the samples were measured by thermal ionization mass spectrometry, the most precise analytical method for the determination of stable mineral isotopes. Stable isotopes were also infused in five young men to evaluate the potential of studying mineral utilization and kinetics with stable isotopes. The results of these studies demonstrate that a number of factors can affect mineral absorption, but the specific effects differ for different minerals. Isotopic enrichments could be measured in urine and blood, so kinetic studies of utilization of essential minerals are now feasible with enriched stable isotopes. Continued use of stable isotopes to determine mineral absorption, combined with stable-isotope studies of mineral utilization, balance data, and biochemical indicators of mineral status, should result in a better understanding of mineral requirements and metabolism under a variety of conditions.

9 citations



Journal ArticleDOI
TL;DR: It is proposed that the diminished solubilities of zinc, iron, copper, magnesium, calcium, inorganic phosphate, and citrate in milk are linked to the precipitation of calcium phosphate through one or more mechanisms of coprecipitation.

1 citations