Dietary sitostanol and campestanol: Accumulation in the blood of humans with sitosterolemia and xanthomatosis and in rat tissues

Abstract

Dietary sitostanol has a hypocholesterolemic effect because it decreases the absorption of cholesterol. However, its effects on the sitostanol concentrations in the blood and tissues are relatively unknown, especially in patients with sitosterolemia and xanthomatosis. These patients hyperabsorb all sterols and fail to excrete ingested sitosterol and other plant sterols as normal people do. The goal of the present study was to examine the absorbability of dietary sitostanol in humans and animals and its potential long-term effect. Two patients with sitosterolemia were fed the margarine Benecol (McNeill Nutritionals, Ft. Washington, PA), which is enriched in sitostanol and campestanol, for 7-18 wk. Their plasma cholesterol levels decreased from 180 to 167 mg/dL and 153 to 113 mg/dL, respectively. Campesterol and sitosterol also decreased. However, their plasma sitostanol levels increased from 1.6 to 10.1 mg/dL and from 2.8 to 7.9 mg/dL, respectively. Plasma campestanol also increased. After Benecol withdrawal, the decline in plasma of both sitostanol and campestanol was very sluggish. In an animal study, two groups of rats were fed high-cholesterol diets with and without sitostanol for 4 wk. As expected, plasma and liver cholesterol levels decreased 18 and 53%, respectively. The sitostanol in plasma increased fourfold, and sitostanol increased threefold in skeletal muscle and twofold in heart muscle. Campestanol also increased significantly in both plasma and tissues. Our data indicate that dietary sitostanol and campestanol are absorbed by patients with sitosterolemia and xanthomatosis and also by rats. The absorbed plant stanols were deposited in rat tissues. Once absorbed by sitosterolemic patients, the prolonged retention of sitostanol and campestanol in plasma might increase their atherogenic potential.

Similar serum plant sterol responses of human subjects heterozygous for a mutation causing sitosterolemia and controls to diets enriched in plant sterols or stanols

“…Both controls and heterozygotes seemed to have sufficient capacity to excrete stanols as suggested by the very low stanol serum levels, even after the subjects had consumed the diet enriched in stanols. This is in contrast to sitosterolemia patients, who show distinctly higher serum levels of sitostanol and campestanol on diets enriched in stanols (Connor et al, 2005).…”

Dietary Phytosterols and Phytostanols Alter the Expression of Sterol-Regulatory Genes in SHRSP and WKY <i>inbred</i> Rats

“…200 mg/day) diet. This result is also in part supported by the study of Connor et al [49] which showed that intake of 5 g/kg diet of phytostanols for 4 weeks had no effect on plasma cholesterol levels in Wistar rats compared to control diet. As mentioned earlier, Cyp27a1 is the rate-limiting enzyme for the conversion of cholesterol into bile acids [42] , and Abca1 is responsible for the reverse cholesterol transport of cholesterol from peripheral tissues to the liver for elimination in bile [25] .…”

Plant sterol or stanol esters retard lesion formation in LDL receptor-deficient mice independent of changes in serum plant sterols

“…Second, we also evaluated the effects of plant stanols, because sitosterolemic patients not only have increased serum plant sterol concentrations but also increased serum plant stanol concentrations. As recently indicated by Connor et al (21), plant stanols also are highly absorbed by sitosterolemic subjects and show a prolonged retention time. However, in epidemiological studies, serum plant stanol concentrations are frequently not reported, because sitostanol and campestanol concentrations are much lower and consequently difficult to measure.…”