ω3脂肪酸は過栄養・肥満患者の体重減少に無効

もう1つω3脂肪酸の論文です。

Laura F DeFina, Lucille G Marcoux, Susan M Devers, Joseph P Cleaver, and Benjamin L Willis: Effects of omega-3 supplementation in combination with diet and exercise on weight loss and body composition. Am J Clin Nutr December 15, 2010, doi: 10.3945/​ajcn.110.002741

ω3脂肪酸が過栄養、肥満の患者の体重減少に有効という仮説があるそうです。今回、栄養療法と運動療法は両群で行い、介入群がω3脂肪酸（1日あたりEPA2.5g、DHA0.5g）、対照群がプラセボというRCTで、ω3脂肪酸の体重減少の効果をみました。

結果は介入群(−5.2 kg; 95% CI: −6.0, −4.4 kg)と対照群(−5.8 kg; 95% CI: −6.7, −5.1 kg) で体重減少に有意差を認めませんでした。むしろ対照群のほうが有意差はありませんが、0.61 ± 0.58 kg (P = 0.29)体重が減少していました。

結論として、ω3脂肪酸は過栄養、肥満の患者の体重減少に有効とはいえません。これは妥当な結果だと私は思いますが、いかがでしょうか。

Abstract
Background: In addition to the metabolic and cardiovascular benefits of omega-3 (n−3) fatty acids, several studies have suggested an added weight loss–enhancing benefit to this supplement.

Objective: The objective was to assess whether supplemental omega-3 fatty acids in conjunction with diet and exercise augment weight loss over a 6-mo period.

Design: In a single-institution, placebo-controlled, randomized clinical trial, 128 individuals with a body mass index (in kg/m2) between 26 and 40 were assigned to receive 5 omega-3 [3.0 g eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) at a 5:1 ratio (EPA:DHA)] or placebo capsules daily in conjunction with lifestyle modification. The primary endpoint was weight loss; secondary endpoints included metabolic and psychometric variables. Analyses were by intention-to-treat.

Results: Overweight and obese individuals were assigned to the omega-3 arm (n = 64) or to the placebo arm (n = 64). Subjects in both arms received dietary and exercise counseling. Eighty-one individuals completed the 24-wk study, and the dropout rate was 27%. Subjects in both arms lost an average of >5% of their body weight. No significant differences in weight loss were observed between the omega-3 (−5.2 kg; 95% CI: −6.0, −4.4 kg) and placebo (−5.8 kg; 95% CI: −6.7, −5.1 kg) arms. The absolute mean (±SEM) change difference was 0.61 ± 0.58 kg (P = 0.29). In addition, no significant differences in the other factors assessed were observed.

Conclusion: Omega-3 fatty acids were not effective as an adjunct for weight loss in this otherwise healthy, overweight population.