Supplementation of Test Meals with Fat-Free Phytosterol Products Can Reduce Cholesterol Micellarization during Simulated Digestion and Cholesterol Accumulation by Caco-2 Cells

Abstract

Phytosterols have been shown to reduce cholesterol absorption in humans. Supplementing phytosterols in fat-free formulations, however, has yielded controversial results. In the present study, we investigated the effect of supplementing test meals with different fat-free phytosterol products on cholesterol incorporation into mixed micelles during simulated digestion and accumulation of micellar cholesterol by Caco-2 cells: control orange juice (OJ), orange juice supplemented with either multivitamin/multimineral tablets (MVT), multivitamin/multimineral tablets containing phytosterols (MVT+P), and phytosterol powder (PP). These combinations were added to Ensure-based test meals and spiked with cholesterol of natural isotopic composition or 13C2-cholesterol to differentiate external from endogenous cholesterol. After simulated gastric/small intestinal digestion, micelle fractions were analyzed for cholesterol enzymatically (n = 6-20/product) and by high-performance liquid chromatography-tandem mass spectrometry (n = 12/product) and added to Caco-2 cells to determine the accumulation of 13C2-cholesterol (n = 10-24/product). As compared to OJ, PP and MVT+P significantly decreased cholesterol micellarization (determined enzymatically) by 70 +/- 39 (mean +/- SD) and 70 +/- 39%, respectively (P < 0.001, Bonferroni). The stable isotope experiments revealed that both PP and MVT+P reduced cholesterol micellarization [by 25 +/- 12 (P = 0.055) and 21 +/- 8% (P = 0.020), respectively, Fisher's protected LSD test] and Caco-2 cell accumulation (by 28 +/- 8 and 10 +/- 8%, respectively; P < 0.010, Bonferroni). OJ+P did not inhibit micellarization or accumulation of cholesterol by Caco-2 cells. This study shows that fat-free phytosterol-containing products can significantly inhibit cholesterol micellarization and Caco-2 cell bioaccessibility, albeit to different extents depending on individual formulations. This is most likely explained by inhibition of cholesterol micellarization.

Dietary and host-related factors influencing carotenoid bioaccessibility from spinach (Spinacia oleracea)

“…In the present study, we aimed at systematically investigating selected dietary and to host-related factors potentially influencing carotenoid bioaccessibility from spinach, employing an in vitro gastro-intestinal model, similarly as described earlier (Bohn et al, 2007;Garrett et al, 1999). This is, to our knowledge, the first study highlighting negative effects of dietary abundant minerals, such as magnesium and calcium, on carotenoid bioaccessibility.…”

“…The in vitro digestion protocol was adapted from earlier studies (Bohn et al, 2007;Garrett et al, 1999;Miller et al, 1981). …”

Formation of inclusion complexes of starch with fatty acid esters of bioactive compounds

“…AP, RP, DMSO, d 6 -DMSO were obtained from Sigma-Aldrich, Inc (St. Louis, MO). PE were CoroWise TM plant sterol esters donated by Cargill Incorporated (Wayzata, MN), with the following composition: 30-60% sitosterol, 20-30% campesterol, 15-30% stigmasterol, <10% other sterols and 92.4% total sterols (Bohn et al, 2007).…”

Antiproliferation Properties of Grain Sorghum Dry Distiller’s Grain Lipids in Caco-2 Cells

“…Because the GS-DDG samples were insoluble in the DMEM medium, micelles prepared with taurcholic acid sodium salt, lecithin, and cholesterol were able to solubilize the GS-DDG lipid at all treatment levels tested. While micelles have been used for delivering cholesterol and other sterols to mammalian cells (26), they are unique to a complex lipid extract. The data were thus normalized to the control (cells þ micelles) as cell proliferation was affected by the micelle delivery system resulting in significantly lower percent cell viability compared to the blank (cells -micelles) (data not shown).…”