POSITIONAL DISTRIBUTION OF STEARIC-ACID AND OLEIC-ACID IN A TRIACYLGLYCEROL AND DIETARY CALCIUM-CONCENTRATION DETERMINES THE APPARENT ABSORPTION OF THESE FATTY-ACIDS IN RATS

In this study the effect of the positional distribution of stearic aci d (18:0) and oleic acid (18:1) in a triacylglycerol on absorption of f at, energy and nutrients was investigated in young rats. in addition t he effect of dietary calcium on these variables was studied. Forty rat s were fed purified diets containing either a fat blend high in 2-oleo yl-distearate or a fat blend high in 1-oleoyl-distearate. Both diets w ere given at low (0.3 g/100 g) and high (1.0 g/100 g) dietary calcium concentrations. Total fat absorption, expressed as the percentage of f at intake, was significantly lower in rats fed 2-oleoyl-distearate com pared with 1-oleoyl-distearate at both dietary calcium concentrations. When expressed as absolute figures, the lower fat absorption in rats fed 2-oleoyl-distearate compared with 1-oleoyl-distearate only reached statistical significance at the high dietary calcium concentration. T he reduced absorption of total fat was mainly caused by the lower abso rption of stearic acid. The percentage of, but not absolute, absorptio n of oleic acid and energy were lower in rats fed 2-oleoyldistearate. Absolute and percentage of calcium absorption were lower in rats fed 2 -oleoyl-distearate compared with 1-oleoyl-distearate. Absolute and per centage of magnesium absorption were not significantly affected by the positional distribution of stearic acid and oleic acid in the triacyl glycerol, but were decreased at a high dietary calcium concentration. We concluded that the lowered stearic acid absorption from 2-oleoyl-di stearate compared with 1-oleoyl-distearate might have been due to the greater formation of insoluble calcium and magnesium soaps in the inte stine.