Effect of stanol ester on postabsorptive squalene and retinyl palmitate

Stanol ester dissolved in margarine inhibits cholesterol absorption in general and, despite increasing cholesterol synthesis, decreases serum total and low-density lipoprotein (LDL) cholesterol levels, but its effects on postprandial lipid metabolism are unknown. We performed fat tolerance tests in 11 men at baseline and during short-term stanol ester consumption without and with stanol esters added to the test meal also containing retinol and squalene. Cholesterol, triglycerides, retinyl palmitate, and squalene were analyzed in plasma, chylomicrons, and very-low-density lipoprotein (VLDL) at baseline and 3, 4, 6, 9, 12, and 24 hours after the test meal. Serum total and LDL cholesterol only tended to diminish after the 2-week stanol ester consumption. However, the proportion of plasma plant sterol and cholesterol-precursor sterol to cholesterol was significantly altered, suggesting that cholesterol absorption was diminished and cholesterol synthesis was increased. Postprandial peak times of squalene and retinyl palmitate in plasma, chylomicrons, and VLDL were significantly reduced by stanol esters, but their concentrations in chylomicrons were unchanged. Stanol esters reduced the VLDL squalene peak concentration by 23% (P < .05) and the incremental area under the curve (AUIC) in plasma and VLDL by 22% and 32% (P < .01 for both). Chylomicron remnant metabolism measured with triglycerides only tended to diminish. The effects of stanol esters in the diet only and both in the diet and with supplementation did not differ significantly. We conclude that dietary stanol esters reduce postprandial lipoproteins measured with dietary retinyl palmitate and especially squalene, and the reduction is observed even though serum total and LDL cholesterol are only inconsistently decreased after short-term stanol ester consumption.