Sex and hormonal status influence plasma lipid responses to psyllium.
BACKGROUND
The primary mechanisms by which soluble fiber lowers plasma cholesterol are well known. However, specific effects of fiber on lipoprotein metabolism and how sex and hormonal status influence these effects are not well defined.


OBJECTIVE
The effects of a psyllium supplement in men, premenopausal women, and postmenopausal women were examined to determine the mechanisms by which psyllium lowers plasma LDL-cholesterol concentrations and affects lipoprotein remodeling in the intravascular compartment.


METHODS
We designed a crossover trial in which 24 men, 23 premenopausal women, and 21 postmenopausal women were randomly assigned for 30 d to a fiber supplement (15 g psyllium/d) or a control. Plasma lipids and cholesteryl ester transfer protein and lecithin-cholesterol acyltransferase (phosphatidylcholine-sterol O-acyltransferase) activities were measured after each treatment.


RESULTS
When compared with the control, psyllium intake lowered plasma LDL-cholesterol concentrations by 7-9% (P < 0.0001) without affecting plasma HDL-cholesterol concentrations. An interactive effect between fiber and sex and hormonal status was observed for plasma triacylglycerol. Psyllium supplementation significantly lowered plasma triacylglycerol concentrations in men by 17% and raised triacylglycerol concentrations in postmenopausal women by 16% (P < 0.01). The dietary treatment did not significantly affect plasma triacylglycerol in premenopausal women. Lecithin-cholesterol acyltransferase was unaffected by psyllium intake whereas cholesteryl ester transfer protein activity was 18% lower after psyllium supplementation than after the control treatment (P < 0.0001).


CONCLUSIONS
This trial showed that the psyllium-induced responses to plasma lipids were associated with sex and hormonal status and that psyllium, through its action in the intestinal lumen, indirectly affected the intravascular processing of lipoproteins.
Vega-López
S
S
Department of Nutritional Sciences, University of Connecticut, Storrs 06269, USA. sov98001@uconnvm.uconn.edu
Vidal-Quintanar
R L
RL
Fernandez
M L
ML
D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure / Q000187:drug effects; D002352:Carrier Proteins / Q000097:blood; D002400:Cathartics / Q000494:pharmacology*; D002784:Cholesterol / Q000097:blood*; D053480:Cholesterol Ester Transfer Proteins; D018592:Cross-Over Studies; D004032:Diet; D005260:Female; D006023:Glycoproteins; D006801:Humans; D008074:Lipoproteins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000097:blood; D017698:Postmenopause / Q000378:metabolism*; D017697:Premenopause / Q000378:metabolism*; D011620:Psyllium / Q000494:pharmacology*; D012737:Sex Factors
C506642:CETP protein, human; D002352:Carrier Proteins; D002400:Cathartics; D053480:Cholesterol Ester Transfer Proteins; D006023:Glycoproteins; D008074:Lipoproteins; D011620:Psyllium; D002784:Cholesterol; D007862:Phosphatidylcholine-Sterol O-Acyltransferase