The absorbability by rats of various triglycerides of stearic and oleic acid and the effect of dietary calcium and magnesium.

Rats were fed diets in which the triglycerides contained oleate and stearate as the sole fatty acids. These fatty acids were esterified to specific positions on the glycerol molecule. The triglycerides were 1-stearoyl diolein (SOO), 2-stearoyl diolein (OSO), 2-oleoyl distearin (SOS), 1-oleoyl distearin (OSS), and triolein (OOO). The absorbability of the fatty acid component was measured by the fat balance technique. Two diets, one sufficient and the other deficient in calcium and magnesium, were used. The oleic acid of all of the triglycerides was absorbed almost completely. The following values for the absorbability of the stearate component in the presence and in the absence of the divalent cations were obtained: OSO 98 and 99; SOO 55 OAND 96; SOS 37 and 70; OSS 59 and 60. These patterns of absorbability are discussed in relation to the pathway of triglyceride digestion. If the stearic acid is esterified at the 2-position of the triglyceride, the resulting 2-monostearin is well absorbed. If it is esterified at the 1- or 3-position, it is released as free stearic acid, and in the presence of calcium and magnesium it is poorly absorbed.