The influence of n-3 polyunsaturated fatty acids and very low calorie diet during a short-term weight reducing regimen on weight loss and serum fatty acid composition in severely obese women.

Author: Kunesova M, Braunerova R, Hlavaty P, Tvrzicka E, Stankova B, Skrha J, Hilgertova J, Hill M, Kopecky J, Wagenknecht M, Hainer V, Matoulek M, Parizkova J, Zak A, Svacina S

Author affiliation: Obesity Management Centre, Institute of Endocrinology, Charles University, Prague 1, Czech Republic. mkunesova@endo.cz

Publication date & source: 2006, Physiol Res., 55(1):63-72. Epub 2005 Apr 26.

Publication type: Clinical Trial; Randomized Controlled Trial; Research Support, Non-U.S. Gov't

Polyunsaturated fatty acids of n-3 series (n-3 PUFA) were shown to increase basal fat oxidation in humans. The aim of the study was to compare the effect of n-3 PUFA added to a very low calorie diet (VLCD), with VLCD only during three-week inpatient weight reduction. Twenty severely obese women were randomly assigned to VLCD with n-3 PUFA or with placebo. Fatty acids in serum lipid fractions were quantified by gas chromatography. Differences between the groups were determined using ANOVA. Higher weight (7.55+/-1.77 vs. 6.07+/-2.16 kg, NS), BMI (2.82+/-0.62 vs. 2.22+/-0.74, p<0.05) and hip circumference losses (4.8+/-1.81 vs. 2.5+/-2.51 cm, p<0.05) were found in the n-3 group as compared to the control group. Significantly higher increase in beta-hydroxybutyrate was found in the n-3 group showing higher ketogenesis and possible higher fatty acid oxidation. The increase in beta-hydroxybutyrate significantly correlated with the increase in serum phospholipid arachidonic acid (20:4n-6; r = 0.91, p<0.001). In the n-3 group significantly higher increase was found in n-3 PUFA (eicosapentaenoic acid, 20:5n-3, docosahexaenoic acid, 22:6n-3) in triglycerides and phospholipids. The significant decrease of palmitoleic acid (16:1n-7) and vaccenic acid (18:1n-7) in triglycerides probably reflected lower lipogenesis. A significant negative correlation between BMI change and phospholipid docosahexaenoic acid change was found (r = -0.595, p<0.008). The results suggest that long chain n-3 PUFA enhance weight loss in obese females treated by VLCD. Docosahexaenoate (22:6n-3) seems to be the active component.