Effects of fats high in stearic acid on lipid and lipoprotein concentrations in men.

The effects of beef tallow and cocoa butter, two fats with a high stearic acid content (C18:0), on serum lipid and lipoprotein concentrations were compared with the effects of butter fat and olive oil in 10 middle-aged men. Liquid-formula diets containing 40% of the calories from the test fat were fed in random order for 3 wk each, with lipoprotein concentrations measured on the last five days. Butter fat raised low-density lipoprotein (LDL) concentrations the most (4.23 +/- .15 mmol/L; mean +/- SE). Beef-tallow feeding resulted in significantly lower concentrations of LDL (4.03 +/- 0.18 mmol/L); cocoa butter resulted in even lower concentrations (3.82 +/- .15 mmol/L). The lowest concentration of LDL was observed with olive oil (3.62 +/- 0.18 mmol/L). Fecal excretion of fatty acids, after adjustment for fecal flow, indicated that oleic acid (C18:1) was 99% absorbed, palmitic acid (C16:0) was 96-97% absorbed, and stearic acid was 90-94% absorbed for the three fats containing significant amounts of stearic acid.