Effect of dietary sphingomyelin on absorption and fractional synthetic rate of cholesterol and serum lipid profile in humans

Abstract

BackgroundDiets enriched with sphingolipids may improve blood lipid profiles. Studies in animals have shown reductions in cholesterol absorption and alterations in blood lipids after treatment with sphingomyelin (SM). However, minimal information exists on effect of SM on cholesterol absorption and metabolism in humans. The objective was to assess the effect of SM consumption on serum lipid concentrations and cholesterol metabolism in healthy humans.MethodsTen healthy adult males and females completed a randomized crossover study. Subjects consumed controlled diets with or without 1 g/day SM for 14 days separated by at least 4 week washout period. Serum lipid profile and markers of cholesterol metabolism including cholesterol absorption and synthesis were analyzed.ResultsSerum triglycerides, total, LDL- and VLDL- cholesterol were not affected while HDL cholesterol concentrations were increased (p = 0.043) by SM diet consumption. No change in cholesterol absorption and cholesterol fractional synthesis rate was observed with supplementation of SM compared to control. Intraluminal cholesterol solubilization was also not affected by consumption of SM enriched diet.ConclusionsIn humans, 1 g/day of dietary SM does not alter the blood lipid profile except for an increased HDL-cholesterol concentration and has no effect on cholesterol absorption, synthesis and intraluminal solubilization compared to control.Trial registrationClinicaltrials.gov # NCT00328211

Fractional cholesterol absorption measurements in humans: Determinants of the blood-based dual stable isotope tracer technique

“…In the literature, FCAs of ,10% to .90% have been described for individual healthy subjects in 15 studies. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] The mean values for the studied populations varied from 24% to 70%.…”

“…32 Free cholesterol was isolated by thin layer chromatography (TLC) or the extract was derivatized directly for gas chromatographic (GC) separation. Jones, Woollet, Wang, and Ramprasath 31,[35][36][37]41 used erythrocytes as the target for isotope enrichment measurements in free cholesterol after neutral lipid extraction and sometimes additional TLC separation. 31,[35][36][37] No data have been published on a direct comparison between isotope enrichments measured in plasma free cholesterol and total cholesterol either in erythrocytes or in plasma.…”

“…Bosner 28 28 Plasma GC/MS Ostlund 29 Plasma GC/MS Jones 31 Erythrocyte Automated dual-inlet system for 13 C and 2 H Jakulj 32 Plasma GC/MS Gremaud 33,34 Plasma GC/C/IRMS for 13 C and GC/P/IRMS for 18 O Woolett 35,36 Erythrocyte Automated dual-inlet system for 13 C and 2 H Wang 37 Erythrocyte Automated dual-inlet system for 13 C and 2 H Godin 38 Plasma GC/C/IRMS for 13 C and TC-EA/IRMS for 2 H Pouteau 39 Plasma GC/C/IRMS for 13 C, GC/P/IRMS for 2 H Ramprasath 40 Erythrocyte GC/C/IRMS for 13 C, GC/P/IRMS for 2 H Ramprasath 41 Erythrocyte GC/C/IRMS for 13 C, GC/P/IRMS for 2 H EA/IRMS, elemental analyzer/isotope ratio mass spectrometry; GC/C/IRMS, gas chromatography/combustion/isotope ratio mass spectrometry; GC/MS, gas chromatography/mass spectrometry; GC/P/IRMS, gas chromatography/combustion/isotope ratio mass spectrometry.…”

“…Because of the simplicity of the experimental protocol and analytical requirements, the blood-based dual isotope approach can be considered the method of choice. Fifteen studies have been published applying this technique, [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] much more than other studies applying isotopes in different approaches such as the continuous isotope feeding procedure involving fecal sampling. The large variation of population mean values (24%-70%) described in the literature for healthy subjects brings up questions about the accuracy of the method.…”

Milk Polar Lipids Affect In Vitro Digestive Lipolysis and Postprandial Lipid Metabolism in Mice

“…Rats fed during 12 wk with an anhydrous milk fat diet supplemented with 10% of MPLs, compared with an anhydrous milk fat diet only, had more plasma TGs and PLs but less hepatic cholesterol esters (15). Moreover, 2 studies investigated the ability of milk sphingomyelin to inhibit intestinal absorption of cholesterol (16,17). In healthy humans, 5-wk supplementation with a dairy drink enriched with 2.7 g/d of egg PLs increased circulating blood lipids, which was not observed with 2.8 g/d of MPLs in the drink (18).…”