The Effect of the Level of Dietary Calcium and Magnesium on the Digestibility of Fatty Acids, Simple Triglycerides, and Some Natural and Hydrogenated Fats , ,

Abstract

In a series of tests with simple triglycerides an inverse relationship obtained between the melting point and the coefficient of digestibility. A similar relationship was noted with hydrogenated lards of varying melting points. Although the presence of calcium and magnesium in the diet does not influence the digestibility of low-melting fats, it markedly decreases that of higher-melting simple triglycerides and hydrogenated fats. The digestibilities with and without the divalent ions were as follows: Trilaurin, 70.5 and 97.3; trimyristin, 37.7 and 76.6; tripalmitin, 12.8 and 27.9; and tristearin, 10.6 and 18.9. With respect to several lards the corresponding coefficients of digestibility with and without the calcium-magnesium salts were as follows: Bland lard (m.p., 47.8°C.), 92.4 and 95.8; hydrogenated lard (m.p., 55.4°C.) 58.0 and 77.9; blended hydrogenated lard (m.p., 55.2°C.) 66.2 and 80.0; and hydrogenated lard (m.p., 61°C.) 17.3 and 38.0. The absence of calcium and magnesium from the diet markedly increases the neutral fat-fatty acid fraction at the expense of the soap fraction. This effect is most marked with trilaurin, trimyristin, and the hydrogenated lard samples, and least with tripalmitin and tristearin. In the latter case the bulk of the excreted fat under either dietary regime is in the neutral fat-fatty acid fraction. The effect of calcium and magnesium was a progressive one, being greater the larger the proportion of these salts in the diet. In all cases except in the tests with tripalmitin and tristearin the elimination of calcium and magnesium from the diet resulted in a decrease in stool weight of 50% or more. The removal of calcium and magnesium from the diet resulted in an increase in the digestibility of crude and refined rapeseed oil to 92 and 93%, respectively.