The effect of dietary phytosphingosine on cholesterol levels and insulin sensitivity in subjects with the metabolic syndrome.
BACKGROUND
Sphingolipids, like phytosphingosine (PS) are part of cellular membranes of yeasts, vegetables and fruits. Addition of PS to the diet decreases serum cholesterol and free fatty acid (FFA) levels in rodents and improves insulin sensitivity.


OBJECTIVE
To study the effect of dietary supplementation with PS on cholesterol and glucose metabolism in humans.


METHODS
Twelve men with the metabolic syndrome (MetS) (according to the International Diabetes Federation (IDF) criteria; age 51+/-2 years (mean+/-s.e.m.); body mass index (BMI) 32+/-1 kg/m(2)) were randomly assigned to 4 weeks of PS (500 mg twice daily) and 4 weeks of placebo (P) in a double-blind cross-over study, with a 4-week wash-out period between both interventions. At the end of each intervention anthropometric measures and serum lipids were measured and an intravenous glucose tolerance test (IVGTT) was performed.


RESULTS
Phytosphingosine did not affect body weight and fat mass compared with P. PS decreased serum total cholesterol (5.1+/-0.3 (PS) vs 5.4+/-0.3 (P) mmol/l; P<0.05) and low-density lipoprotein (LDL)-cholesterol levels (3.1+/-0.3 (PS) vs 3.4+/-0.3 (P) mmol/l; P<0.05), whereas it did not alter serum triglyceride and high-density lipoprotein (HDL)-cholesterol levels. In addition, PS lowered fasting plasma glucose levels (6.2+/-0.3 (PS) vs 6.5+/-0.3 (P) mmol/l; P<0.05). PS increased the glucose disappearance rate (K-value) by 9.9% during the IVGTT (0.91+/-0.06 (PS) vs 0.82+/-0.05 (P) %/min; P<0.05) at similar insulin levels, compared with P, thus implying enhanced insulin sensitivity. PS induced only minor gastrointestinal side effects.


CONCLUSIONS
Dietary supplementation of PS decreases plasma cholesterol levels and enhances insulin sensitivity in men with the MetS.
Snel
M
M
Department of General Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands. m.snel@lumc.nl
Sleddering
M A
MA
Pijl
H
H
Nieuwenhuizen
W F
WF
Frölich
M
M
Havekes
L M
LM
Romijn
J A
JA
Jazet
I M
IM
D001786:Blood Glucose / Q000378:metabolism*; D002784:Cholesterol / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D004041:Dietary Fats / Q000008:administration & dosage*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000188:drug therapy*; D008875:Middle Aged; D013107:Sphingolipids / Q000494:pharmacology*; D013110:Sphingosine / Q000494:pharmacology*; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D008078:Cholesterol, LDL; D004041:Dietary Fats; D007328:Insulin; D013107:Sphingolipids; D014280:Triglycerides; D002784:Cholesterol; D013110:Sphingosine