Effect of dietary calcium on growth, calcium, magnesium and phosphorus contents and fatty acid composition of individual tissues in rats.

Abstract

In order to determine the effects of diet containing three calcium (Ca) levels (none, 0.8 or 2.4%) on rats, the Ca, magnesium and phosphorus contents, fatty acid composition in tissues as well as their growth were examined. In the groups fed with Ca-free and 2.4% Ca diet the growth of rats was suppressed compared with that of a control group (0.8% Ca). In both groups the relative weight of brain with respect to the body weight increased and in the group fed with 2.4% Ca diet, the weight of kidney increased both relatively and absolutely. Ca content in all tissues except the kidney of female rats decreased to various extents in the group fed with Ca-free diet. In the group fed with 2.4% Ca diet, the Ca content increased markedly only in the kidney. In the group fed with 2.4% Ca diet, magnesium content decreased only in bone, and phosphorus content was not affected by any dietary Ca level. Fatty acid compositions of the heart, liver and kidney changed as dietary Ca levels were varied, but no change was observed in the brain. Namely, in the group fed with 2.4% Ca diet, oleic and eicosatrienoic acids increased, but linoleic and arachidonic acids decreased. On the other hand, consistent changes of composition in the Ca-free diet group were not observed in any individual tissue of either sex. From these results, it was concluded that the growth of rats was suppressed in the groups fed not only with Ca-free but also high Ca level diets and that the mineral content and fatty acid composition in various tissues changed as the dietary Ca level was varied.