Long-chain polyunsaturated fatty acid supplementation had no effect on body weight but reduced energy intake in overweight and obese women.

Longer-chain polyunsaturated fatty acids may have greater appetite-suppressing effects than shorter-chain, monosaturated, and saturated fatty acids. Because fish oils are predominantly composed of n-3 long-chain polyunsaturated fatty acid and may assist in the treatment of obesity comorbidities, their effect on body weight and body mass index is of interest. We hypothesized that daily supplementation with docosahexaenoic acid (DHA)-rich oil would reduce energy intake and body weight in overweight and obese women compared with supplementation with oleic acid (OA) rich oil. A double-blinded, randomized, parallel intervention was conducted. Body mass index (in kilograms per meter squared), body weight (in kilograms), body fat (in percent), and lean tissue (in kilograms) were measured at baseline and 12 weeks after intervention with DHA or OA. Diet diaries were also completed at these time points for estimation of energy and macronutrient intake. Subjects reported significantly lower energy (P = .020), carbohydrate (g) (P = .037), and fat (g) (P = .045) intake after DHA compared with OA. Body mass or composition was not affected by treatment, although a fall in body weight in the DHA group approached statistical significance (P = .089). Daily ingestion of DHA over a 12-week period may reduce energy intake in overweight and obese females, but longer-term and adequately powered studies using subjects of both sexes are needed. Other factors that should be considered include the following: the choice of control, the body mass index category of subjects, and ways of improving the compliancy and accuracy of dietary assessment.

Effect of different long-chain fatty acids on cholecystokinin release in vitro and energy intake in free-living healthy males.

Long-chain fatty acids have been shown to suppress appetite and reduce energy intake (EI) by stimulating the release of gastrointestinal hormones such as cholecystokinin (CCK). The effect of NEFA acyl chain length on these parameters is not comprehensively understood. An in vitro screen tested the capacity of individual NEFA (C12 to C22) to trigger CCK release. There was a gradient in CCK release with increasing chain length. DHA (C22) stimulated significantly (P < 0.01) more CCK release than all other NEFA tested. Subsequently, we conducted a randomised, controlled, crossover intervention study using healthy males (n 18). The effects of no treatment (NT) and oral doses of emulsified DHA-rich (DHA) and oleic acid (OA)-rich oils were compared using 24 h EI as the primary endpoint. Participants reported significantly (P = 0.039) lower total daily EI (29 % reduction) with DHA compared to NT. There were no differences between DHA compared to OA and OA compared to NT. There was no between-treatment difference in the time to, or EI of, the first post-intervention eating occasion. It is concluded that NEFA stimulate CCK release in a chain length-dependent manner up to C22. These effects may be extended to the in vivo setting, as a DHA-based emulsion significantly reduced short-term EI.