Kefir consumption does not alter plasma lipid levels or cholesterol fractional synthesis rates relative to milk in hyperlipidemic men: a randomized controlled trial [ISRCTN10820810].
BACKGROUND
Fermented milk products have been shown to affect serum cholesterol concentrations in humans. Kefir, a fermented milk product, has been traditionally consumed for its potential health benefits but has to date not been studied for its hypocholesterolemic properties.


METHODS
Thirteen healthy mildly hypercholesterolemic male subjects consumed a dairy supplement in randomized crossover trial for 2 periods of 4 wk each. Subjects were blinded to the dairy supplement consumed. Blood samples were collected at baseline and after 4 wk of supplementation for measurement of plasma total, low-density lipoprotein, and high-density lipoprotein cholesterol and triglyceride concentrations, as well as fatty acid profile and cholesterol synthesis rate. Fecal samples were collected at baseline and after 2 and 4 wk of supplementation for determination of fecal short chain fatty acid level and bacterial content.


RESULTS
Kefir had no effect on total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol or triglyceride concentrations nor on cholesterol fractional synthesis rates after 4 wk of supplementation. No significant change on plasma fatty acid levels was observed with diet. However, both kefir and milk increased (p < 0.05) fecal isobutyric, isovaleric and propionic acids as well as the total amount of fecal short chain fatty acids. Kefir supplementation resulted in increased fecal bacterial content in the majority of the subjects.


CONCLUSIONS
Since kefir consumption did not result in lowered plasma lipid concentrations, the results of this study do not support consumption of kefir as a cholesterol-lowering agent.
St-Onge
Marie-Pierre
MP
School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, Canada. mstong@po-box.mcgill.ca
Farnworth
Edward R
ER
Savard
Tony
T
Chabot
Denise
D
Mafu
Akier
A
Jones
Peter J H
PJ
D000328:Adult; D000818:Animals; D002784:Cholesterol / Q000096:biosynthesis*; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D043302:Cultured Milk Products; D003611:Dairy Products; D004041:Dietary Fats; D019587:Dietary Supplements; D004311:Double-Blind Method; D005243:Feces / Q000737:chemistry / Q000382:microbiology; D005285:Fermentation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006937:Hypercholesterolemia / Q000178:diet therapy* / Q000378:metabolism*; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D008892:Milk; D019936:Probiotics / Q000494:pharmacology*; D016037:Single-Blind Method; D014280:Triglycerides / Q000145:classification
D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004041:Dietary Fats; D008055:Lipids; D014280:Triglycerides; D002784:Cholesterol