Association of antipsychotic drug-induced weight gain with a 5-HT2C receptor gene polymorphism

A side-effect of treatment with antipsychotic drugs for schizophrenia is increased body fat, which leads to further morbidity and poor adherence to treatment. The 5-hydroxytryptamine 2C receptor (5-HT2C) has been associated with this effect; we aimed to establish whether a genetic polymorphism of the promoter region of this receptor affects weight gain after drug treatment in first-episode patients with schizophrenia. We noted significantly less weight gain in patients with the -759T variant allele (p=0.0003) than in those without this allele, who were more likely to have substantial (>7%) weight gain (p=0.002). We have identified a genetic factor that is associated with antipsychotic drug-induced weight gain.

Effect of chronic consumption of almonds on body weight in healthy humans

Small changes of diet may reduce CVD risk. One example is the inclusion of nuts. They are rich in fibre, unsaturated fatty acids and phytonutrients. However, their fat content and energy density raise concerns that chronic consumption will promote weight gain. Randomised intervention studies are required to evaluate whether this concern is well founded. This study's aim was to determine if the inclusion of a 1440 kJ serving of almonds in the daily diet results in positive energy balance, and body composition change. During a 23-week cross-over design study, participants were required to consume almonds for 10 weeks and were provided no advice on how to include them in their diet. For another 10 weeks (order counter-balanced), participants followed their customary diet and there was a 3-week washout between. The study group consisted of twenty women. Potential mechanisms of energy dissipation were measured. Ten weeks of daily almond consumption did not cause a change in body weight. This was predominantly due to compensation for the energy contained in the almonds through reduced food intake from other sources. Moreover, inefficiency in the absorption of energy from almonds was documented (P <0·05). No changes in resting metabolic rate, thermic effect of food or total energy expenditure were noted. A daily 1440 kJ serving of almonds, sufficient to provide beneficial effects on cardiovascular risk factors, may be included in the diet with limited risk of weight gain. Whether this can be generalised to other high-fat energy dense foods warrants evaluation.

The Effectiveness of Weight Management Interventions in Breastfeeding Women—A Systematic Review and Critical Evaluation

Background: The postpartum period is a vulnerable time for excess weight retention, particularly for the increasing number of women who are overweight at the start of their pregnancy and subsequently find it difficult to lose additional weight gained during pregnancy. Although postpartum weight management interventions play an important role in breaking this potentially vicious cycle of weight gain, the effectiveness of such interventions in breastfeeding women remains unclear. Our aim was to systematically review the literature about the effectiveness of weight management interventions in breastfeeding women.

Methods: Seven electronic databases were searched for eligible papers. Intervention studies included were carried out exclusively in breastfeeding mothers, ≤2 years postpartum and with a body mass index greater than 18.5 kg/m2, with an outcome measure of change in weight and/or body composition.

Results: Six studies met the selection criteria, and were stratified according to the type of intervention and outcome measures. Despite considerable heterogeneity among studies, the dietary-based intervention studies appeared to be the most efficacious in promoting weight loss; however, few studies were tailored toward the needs of breastfeeding women.

Conclusions: Weight management interventions which include an energy-restricted diet may play a key role in successful postpartum weight loss for breastfeeding mothers.

Metabolic and structural properties of human obestatin {1-23} and two fragment peptides

Obestatin is a peptide produced in the oxyntic mucosa of the stomach and co-localizes with ghrelin on the periphery of pancreatic islets. Several studies demonstrate that obestatin reduces food and water intake, decreases body weight gain, inhibits gastrointestinal motility, and modulates glucose-induced insulin secretion. In this study we evaluated the acute metabolic effects of human obestatin {1-23} and fragment peptides {1-10} or {11-23} in high-fat fed mice, and then investigated their solution structure by NMR spectroscopy and molecular modelling. Obestatins {1-23} and {11-23} significantly reduced food intake (86% and 90% respectively) and lowered glucose responses to feeding, whilst leaving insulin responses unchanged. No metabolic changes could be detected following the administration of obestatin (1-10). In aqueous solution none of the obestatin peptides possessed secondary structural features. However, in a 2,2,2-trifluoroethanol (TFE-d(3))-H2O solvent mixture, the structure of obestatin {1-23} was characterized by an a-helix followed by a single turn helix conformation between residues Pro(4) and Gln(15) and His(19) and Ala(22) respectively. Obestatin {1-10} showed no structural components whereas {11-23} contained an a-helix between residues Val(14) and Ser(20) in a mixed solvent. These studies are the first to elucidate the structure of human obestatin and provide clear evidence that the observed a-helical structures are critical for in vivo activity. Future structure/function studies may facilitate the design of novel therapeutic agents based on the obestatin peptide structure. (C) 2010 Elsevier Inc. All rights reserved.