Objective: Lifestyle and genetic factors interact in the development of obesity and the metabolic syndrome. The molecular mechanisms underlying the beneficial dietary modifications are, however, unclear. We aimed to examine the effect of the longterm moderate weight reduction on gene expression in adipose tissue (AT) and to identify genes and gene clusters responsive to treatment and thereby likely contributing to the development of the metabolic syndrome. Design: Randomized controlled and individualized weight reduction intervention. Subjects: Forty-six subjects with impaired fasting glycemia or impaired glucose tolerance and features of metabolic syndrome, aged 6077 years were randomized either to a weight reduction (WR) (n ¼ 28) or a control (n ¼ 18) group lasting for 33 weeks. Measurements: Oral and intravenous glucose tolerance tests and subcutaneous AT biopsies were performed before and after the intervention. Gene expression of AT was studied using microarray technology in subgroups of WR (with weight reduction X5%, n ¼ 9) and control group (n ¼ 10). The results were confirmed using quantitative PCR. Results: In the WR group, glucose metabolism improved. Moreover, an inverse correlation between the change in S I and the change in body weight was found (r ¼ À0.44, P ¼ 0.026). Downregulation of gene expression (Po0.01) involving gene ontology groups of extracellular matrix and cell death was seen. Such changes did not occur in the control group. The tenomodulin-gene was one of the most downregulated genes (À39716%, Po0.0001). Moreover, its expression correlated with insulin sensitivity (r ¼ À0.34, P ¼ 0.005) before the intervention and with body adiposity both before (r ¼ 0.42, P ¼ 0.007) and after (r ¼ 0.30, P ¼ 0.056) the intervention. Conclusion: Genes regulating the extracellular matrix and cell death showed a strong downregulation after long-term weight reduction. This likely reflects a new stable state at the molecular level in AT. Further studies are warranted to elucidate the mechanisms of these genetic factors.

Dietary carbohydrate modification with rye and pasta or oat, wheat, and potato differentially modulates the gene expression profile in abdominal subcutaneous adipose tissue, even in the absence of weight loss.

Long-term intake of cereal foods with differing postprandial insulin responses may be a factor that modulates the inflammatory status in individuals with the metabolic syndrome.

This study investigated the effects of a heavy resistance exercise session (RES) with the oral daytime ingestion of melatonin on the physiological responses and acute performance. In a randomized and double-blind controlled study 10 healthy male subjects undertook an 80 min intensive hypertrophic RES for major muscles of the lower and upper extremities. The subjects were studied on two occasions receiving either melatonin (6 mg) or placebo (6 mg) in random order 60 min before each RES. Blood samples were taken from an antecubital vein both in fasting conditions in the morning and before RES (pre 60 min, pre 0 min), during RES (middle) and after RES (post 0 min, post 15 min, post 30 min, post 60 min). Maximal jumping ability and maximal strength in bench press and squat were measured before and immediately after RES in which there were no differences between the melatonin and placebo groups. The serum melatonin concentration increased significantly (P<0.05-0.001) in the melatonin group following oral ingestion of melatonin and was elevated at every time point after that. The concentration reached a peak value of 1171.3+/-235.2 pg/ml in 60 min at pre 0. Serum melatonin increased slightly but significantly (P<0.05) also in the placebo group just before RES, in the middle of RES and after RES (post 0, post 15). There were large differences (P<0.01-0.001) in the serum melatonin concentration between the groups at all time points. There were no differences in the growth hormone (GH), testosterone and cortisol peak concentrations at any time points between the groups but the area under the curve of GH during RES (P<0.01) and during the 60 min after RES (P<0.05) was lower in the melatonin condition. In conclusion, the present findings give evidence that oral ingestion of melatonin (6 mg) during daytime with heavy resistance exercise may slightly decrease GH concentrations. On the other hand, it seems that melatonin administration during daytime does not have any acute (1-2 h) effects either on the maximal jumping ability or on the maximal strength.