Dietary supplementation with n-3 PUFA does not promote weight loss when combined with a very-low-energy diet

Br J Nutr. 2012 Oct 28;108(8):1466-74. doi: 10.1017/S0007114511006817. Epub 2012 Jan 3.


Obesity is associated with elevated levels of inflammation and metabolic abnormalities which are linked to CVD. The aim of the present study was to investigate whether long-chain n-3 PUFA (LCn-3PUFA), combined with a very-low-energy diet (VLED), facilitated weight loss and weight maintenance, and improvements in blood lipids and inflammatory mediators. This was a double-blind, randomised, controlled trial with two parallel groups. For 14 weeks, one group consumed 6 × 1 g capsules/d of monounsaturated oil (placebo group, PB), and the other group consumed 6 × 1 g capsules/d of LCn-3PUFA (fish oil group, FO), each comprising 70 mg EPA and 270 mg DHA. Both groups were on VLED for 4 weeks (n 14 PB, n 18 FO), which was then followed by 10 weeks of weight maintenance (n 12 PB, n 17 FO). Fasting blood samples, anthropometric measurements and 3 d food diaries were collected at baseline, at 4 and 14 weeks. A greater-than-2-fold increase occurred in plasma levels of EPA and DHA in the FO group (P < 0·001). At 4 weeks, the mean weight loss was -6·54 (SD 2·08) kg (-6·9%) for PB and -6·87 (SD 1·83) kg (-7·7%) for FO. At week 14, after the maintenance phase, there was a further mean decrease in weight, -1·57 (SD 3·7) kg (1·85%) for PB and -1·69 (SD 2·32) kg (-1·9%) for FO. Both groups experienced improved metabolic profiles and there was a significant reduction in fat mass for the FO group at week 14 but not for PB. However, it would appear that supplementation with LCn-3PUFA had no significant effect on weight loss or weight maintenance over the 14 weeks.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adipose Tissue / drug effects*
  • Adipose Tissue / metabolism
  • Adult
  • Caloric Restriction*
  • Diet, Reducing
  • Dietary Fats / blood
  • Dietary Fats / pharmacology*
  • Dietary Fats / therapeutic use
  • Dietary Supplements*
  • Docosahexaenoic Acids / blood
  • Double-Blind Method
  • Eicosapentaenoic Acid / blood
  • Fatty Acids, Omega-3 / blood
  • Fatty Acids, Omega-3 / pharmacology*
  • Fatty Acids, Omega-3 / therapeutic use
  • Female
  • Humans
  • Male
  • Middle Aged
  • Obesity / diet therapy
  • Obesity / drug therapy*
  • Obesity / metabolism
  • Weight Loss / drug effects*


  • Dietary Fats
  • Fatty Acids, Omega-3
  • Docosahexaenoic Acids
  • Eicosapentaenoic Acid