Randomized trial of weight-loss-diets for young adults varying in fish oil content

ArticleinInternational Journal of Obesity 31(10):1560-6 · November 2007with34 Reads
DOI: 10.1038/sj.ijo.0803643 · Source: PubMed
Abstract
To investigate the effect of including seafood and fish oils, as part of an energy-restricted diet, on weight loss in young overweight adults. Randomized controlled trial of energy-restricted diet varying in fish and fish oil content was followed for 8 weeks. Subjects were randomized to one of four groups: (1) control (sunflower oil capsules, no seafood); (2) lean fish (3 x 150 g portions of cod/week); (3) fatty fish (3 x 150 g portions of salmon/week); (4) fish oil (DHA/EPA capsules, no seafood). The macronutrient composition of the diets was similar between the groups and the capsule groups, were single-blinded. A total of 324 men and women aged 20-40 years, BMI 27.5-32.5 kg/m(2) from Iceland, Spain and Ireland. Anthropometric data were collected at baseline, midpoint and endpoint. Confounding factors were accounted for, with linear models, for repeated measures with two-way interactions. The most important interactions for weight loss were (diet x energy intake), (gender x diet) and (gender x initial-weight). An average man in the study (95 kg at baseline receiving 1600 kcal/day) was estimated to lose 3.55 kg (95% CI, 3.14-3.97) (1); 4.35 kg (95% CI, 3.94-4.75) (2); 4.50 kg (95% CI, 4.13-4.87) (3) and 4.96 kg (95% CI, 4.53-5.40) on diet (4) in 4 weeks, from baseline to midpoint. The weight-loss from midpoint to endpoint was 0.45 (0.41-0.49) times the observed weight loss from baseline to midpoint. The diets did not differ in their effect on weight loss in women. Changes in measures of body composition were in line with changes in body weight. In young, overweight men, the inclusion of either lean or fatty fish, or fish oil as part of an energy-restricted diet resulted in approximately 1 kg more weight loss after 4 weeks, than did a similar diet without seafood or supplement of marine origin. The addition of seafood to a nutritionally balanced energy-restricted diet may boost weight loss.
    • "Nevertheless, results have not been unanimous among human studies, with previous reports showing reduced body fat and increased resting fat oxidation in healthy adults [107], and reduced trunk fat and adipocyte diameter in type 2 diabetes patients, without changes in insulin sensitivity as measured by an insulin clamp [108]. When coupled with energy restricted diets, there was no effect of n-3 PUFA on body fat of young athletes [109] or overweight women [110], but there was a report of greater weight loss and waist circumference reduction in overweight men [111]. When fish oil was added to exercise regimens, there was an independent effect on body fat reduction in overweight and obese adults [112], but no effect in lean young male volunteers [113]. "
    [Show abstract] [Hide abstract] ABSTRACT: Omega-3 polyunsaturated fatty acids (n-3 PUFA) of marine origin, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), have been long studied for their therapeutic potential in the context of type 2 diabetes, insulin resistance, and glucose homeostasis. Glaring discordance between observations in animal and human studies precludes, to date, any practical application of n-3 PUFA as nutritional therapeutics against insulin resistance in humans. Our objective in this review is to summarize current knowledge and provide an up-to-date commentary on the therapeutic value of EPA and DHA supplementation for improving insulin sensitivity in humans. We also sought to discuss potential mechanisms of n-3 PUFA action in target tissues, in specific skeletal muscle, based on our recent work, as well as in liver and adipose tissue. We conducted a literature search to include all preclinical and clinical studies performed within the last two years and to comment on representative studies published earlier. Recent studies support a growing consensus that there are beneficial effects of n-3 PUFA on insulin sensitivity in rodents. Observational studies in humans are encouraging, however, the vast majority of human intervention studies fail to demonstrate the benefit of n-3 PUFA in type 2 diabetes or insulin-resistant non-diabetic people. Nevertheless, there are still several unanswered questions regarding the potential impact of n-3 PUFA on metabolic function in humans.
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    • "Munro and Garg [25] conducted a double-blind randomised, placebo controlled intervention and demonstrated a greater percentage reduction in weight and BMI for females in the fish oil supplementation group compared to control. In an earlier study, Thorsdottir et al. [26] explored the effects of fish consumption and fish oil supplementation as part of an energyrestricted diet in an overweight adult population. Greatest weight loss was evident in males who included fish or fish oil supplements, but not females. "
    [Show abstract] [Hide abstract] ABSTRACT: Background/Objectives: Restricting energy intake for weight management in older adults has potential to adversely affect nutritional status and result in impairment of an already compromised immune system. Investigation of alternative strategies to combat adiposity and sustain lean muscle mass in older adults are warranted to minimise the risk of developing chronic diseases. Long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may play an important role through their impact on increased fat oxidation and reduced inflammation. This study aimed to examine the association between erythrocyte membrane LCn-3PUFA and anthropometric measures in an older population.
    Full-text · Article · Apr 2016
    • "Of note, the increased n-6:n-3 ratio in these mice was accompanied with increased obesity, insulin resistance and hepatic steatosis [11][12][13] . However, the study by Thorsdottir et al. demonstrated that inclusion of lean fish in low energy diets was as efficient as inclusion of fatty fish or fish oil supplement in accentuating weight loss [10]. In C57BL/6 J mice, intake of lean seafood such as white crab meat, scallop and a mixture of cod and scallops has been demonstrated to attenuate obesity and hepatic steatosis induced by high fat, high sucrose feeding [14,15]. "
    [Show abstract] [Hide abstract] ABSTRACT: The content of the marine n-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is far lower in lean than in fatty seafood. Cod fillets contain less than 2 g fat per kg, whereof approximately 50% is EPA and DHA. However, a large fraction of these n-3 PUFAs are present in the phospholipid (PL) fraction and may have high bioavailability and capacity to change the endocannabinoid profile. Here we investigated whether exchanging meat from a lean terrestrial animal with cod in a background Western diet would alter the endocannabinoid tone in mice and thereby attenuate obesity development and hepatic lipid accumulation. Accordingly, we prepared iso-caloric diets with 15.1 energy (e) % protein, 39.1 e% fat and 45.8 e% carbohydrates using freeze-dried meat from cod fillets or pork sirloins, and using a combination of soybean oil, corn oil, margarine, milk fat, and lard as the fat source. Compared with mice receiving diets containing pork, mice fed cod gained less adipose tissue mass and had a lower content of hepatic lipids. This was accompanied by a lower n-6 to n-3 ratio in liver PLs and in red blood cells (RBCs) in the mice. Furthermore, mice receiving the cod-containing diet had lower circulating levels of the two major endocannabinoids, N-arachidonoylethanolamine and 2-arachidonoylglycerol. Together, our data demonstrate that despite the relatively low content of n-3 PUFAs in cod fillets, the cod-containing diet could exert beneficial metabolic effects.
    Full-text · Article · Apr 2016
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