Olestra ingestion and dietary fat absorption in humans

The effect of olestra, a zero-calorie fat replacement, on the absorption of dietary fat was determined with a dual-isotope technique in 67 healthy male subjects. After a 30-d adaptation period in which they consumed potato chips which delivered either 10 g/d olestra or 10 g/d triglyceride under free-living conditions, the subjects were housed in a metabolic ward and given 0, 8, 20 or 32 g olestra in potato chips. The chips were eaten as part of a breakfast containing about 38 g of fat, about 0.16 mg of 14C-triolein, and a nonabsorbable marker, 51CrCl3. Feces were collected for 7 d, and aliquots of the two daily collections containing the highest levels of 51Cr were oxidized. The CO2 was collected, and 14C content was determined by liquid scintillation spectrometry. The fractional absorption of 14C-triolein was calculated from the average ratios of 14C/51Cr dosed and measured in the feces. Olestra had a slight but significant dose-response effect on triglyceride absorption: the highest olestra dose (32 g) reduced absorption by 1.2%. This effect is not nutritionally significant with respect to either availability of essential fatty acids or energy intake.