DIFFERENTIAL ABSORPTION OF PLANT STEROLS IN THE DOG

Abstract

Eight adult female dogs (8 to 10 kg) with thoracic duct fistula were fed 5 to 10% solutions of mixed plant sterols in oleic acid, corn oil, or butter. The lymph, which flowed at a rate of 20 to 50 ml per hour, was drained for 18 to 26 hours. Each 2-hour collection was analyzed separately for cholesterol and plant sterols. Under comparable conditions and following a single meal containing plant sterol, about 35 mg of this sterol was transferred to lymph in 24 hours when corn oil was fed and 130 mg in the case of butterfat. At the time of maximum sterol absorption (8 to 12 hours after feeding) as much as 15% of the total lymph sterol was contributed by the plant sterols. Significant absorption of both β- and γ-sitosterol was observed, the γ-isomer being assimilated some 4 to 5 times as readily as the β-isomer. About 50% of the total lymph cholesterol was esterified. Essentially all of the absorbed plant sterol was free.