Effect of polydextrose and soluble maize fibre on energy metabolism, metabolic profile and appetite control in overweight men and women.

High-fibre diets offer several beneficial health effects. The objective of the present study was to investigate whether replacement of 30% of the available carbohydrates with polydextrose (PDX) or soluble maize fibre (SCF) at breakfast and lunch would result in an increased fat oxidation rate and satiety, which may be of relevance for body weight control and diabetes prevention. In a single-blind, randomised cross-over study, eighteen overweight men and women underwent four different dietary interventions, which consisted of a PDX diet, a SCF diet and two control diets (full energetic and isoenergetic, comparable with PDX with respect to g or energy percentage of macronutrients, respectively). Glycaemic profile, energy expenditure and substrate oxidation were measured for 24h in a respiration chamber. Circulating insulin, NEFA and TAG concentrations were determined over a 14h period during daytime. Appetite ratings were assessed using visual analogue scales. The replacement of available carbohydrates with PDX or SCF reduced the peak glucose response, which was accompanied by reduced postprandial insulin responses. Moreover, higher concentrations of circulating NEFA were observed after consumption of both fibre diets, which were accompanied by an increased fat oxidation over 24h. This effect was mainly attributed to the lower energetic value of the fibre diets and not to the fibres per se. Besides increasing fat oxidation, PDX exerted a pronounced suppressive effect on appetite ratings. The replacement of available carbohydrates with PDX may be of special interest because of its beneficial effects on metabolic profile and it may affect body weight control in the long term

Effect of aging on beta-adrenergically mediated thermogenesis in men.

Department of Human Biology, Maastricht University, 6200 MD Maastricht, The Netherlands. The age-dependent alterations in beta-adrenergically mediated thermogenesis were investigated in 11 young (mean +/- SE age: 21.9 +/- 0.5 yr) and 9 older (52.9 +/- 2.1 yr) men during intravenous infusion of the nonselective beta-agonist isoprenaline (Iso). The older men had higher basal plasma norepinephrine (327.7 +/- 35.8 vs. 159.0 +/- 18.2 pg/ml, P < 0.001) and epinephrine (75.1 +/- 18.1 vs. 29.1 +/- 5.3 pg/ml, P < 0.05) concentrations than the young. The beta-adrenergically mediated thermogenesis was diminished in the older men, as reflected by the significantly higher plasma Iso concentration needed to increase resting energy expenditure by 15% (236.1 +/- 51.0 vs. 107.6 +/- 11.4 pg/ml, P < 0.05). Additionally, both dose (39.4 +/- 6.6 vs. 19.1 +/- 1.5 ng . kg fat-free mass-1 . min-1, P < 0.01) and plasma concentration (332.2 +/- 59.1 vs. 119.3 +/- 14.0 pg/ml, P < 0.01) of Iso needed to increase resting heart rate by 25 beats/min were higher in older than in younger subjects, suggesting that the age-related decline in beta-adrenergic sensitivity is a generalized defect not related to a specific tissue or response. In conclusion, aging is associated with a diminished beta-adrenergically mediated thermogenesis. This blunted thermogenic response may contribute to a positive energy balance and thus promote increased fat storage and obesity

Plasma free Fatty Acid uptake and oxidation are already diminished in subjects at high risk for developing type 2 diabetes.

Diabetes 2001 Nov;50(11):2548-54 Related Articles, Books, LinkOut Plasma free Fatty Acid uptake and oxidation are already diminished in subjects at high risk for developing type 2 diabetes. Mensink M, Blaak EE, van Baak MA, Wagenmakers AJ, Saris WH. Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, the Netherlands. [email protected] The objective of this study was to investigate to what extent disturbances in fatty acid metabolism found in type 2 diabetes are already present in subjects at high risk for developing diabetes (i.e., impaired glucose tolerance [IGT]). Components of fatty acid metabolism were measured in male subjects with IGT during postabsorptive conditions and during 60 min of exercise (50% VO(2max)) with the use of the stable isotope tracer [U-(13)C]palmitate in combination with indirect calorimetry, and those values were compared with previously published findings in male type 2 diabetic and male obese subjects. No differences were found between groups in energy expenditure and in total fat and carbohydrate oxidation. Rate of appearance and rate of disappearance of plasma free fatty acid (FFA) were lower in subjects with IGT and type 2 diabetes compared with obese subjects (P < 0.05). Plasma FFA oxidation was lower in subjects with IGT and type 2 diabetes compared with obese subjects at rest and tended to be lower during exercise (rest: 3.7 +/- 0.3, 4.4 +/- 0.6, and 6.9 +/- 1.0 micromol. kg fat-free mass [FFM](-1). min(-1), P < 0.01; exercise: 15.0 +/- 1.7, 14.1 +/- 1.9, and 19.6 +/- 1.5 micromol. kg FFM(-1). min(-1) for IGT, type 2 diabetic, and obese subjects, respectively, P = 0.07). Triglyceride-derived fatty acid oxidation, however, was elevated in subjects with IGT and type 2 diabetes during exercise (3.6 +/- 1.4, 1.4 +/- 1.4, and -4.0 +/- 2.0 micromol. kg FFM(-1). min(-1) for IGT, type 2 diabetic, and obese subjects, respectively; P < 0.05). These data demonstrate that male subjects with a prediabetic condition (IGT) have the same defects in fatty acid utilization as subjects with type 2 diabetes, suggesting that these disturbances may play an important role in the progression from IGT to type 2 diabetes

Study on Lifestyle Intervention and Impaired Glucose Tolerance Maastricht (SLIM): preliminary results after one year

AIMS: Important risk factors for the progression from impaired glucose tolerance to type II diabetes mellitus are obesity, diet and physical inactivity. The aim of this study is to evaluate the effect of a lifestyle-intervention programme on glucose tolerance in Dutch subjects with impaired glucose tolerance (IGT). METHODS: A total of 102 subjects were studied, randomised into two groups. Subjects in the intervention group received regular dietary advice, and were stimulated to lose weight and to increase their physical activity. The control group received only brief information about the beneficial effects of a healthy diet and increased physical activity. Before and after the first year, glucose tolerance was measured and several other measurements were done. RESULTS: Body weight loss after 1 y was higher in the intervention group. The 2-h blood glucose concentration decreased 0.8±0.3 mmol/l in the intervention group and increased 0.2±0.3 mmol/l in the control group (P<0.05). Body weight loss and increased physical fitness were the most important determinants of improved glucose tolerance and insulin sensitivity. CONCLUSION: A lifestyle-intervention programme according to general recommendations is effective and induces beneficial changes in lifestyle, which improve glucose tolerance in subjects with IGT. Body weight loss and increased physical fitness were the most important determinants of improved glucose tolerance and insulin sensitivity

Postprandial interleukin-6 release from skeletal muscle in men with impaired glucose tolerance can be reduced by weight loss

Context: Obesity and type 2 diabetes mellitus are associated with increased levels of IL-6, a marker of inflammation. Objective: This study addressed the question of whether IL-6 was released from skeletal muscle after a high-fat meal in men with impaired glucose tolerance (IGT), a prediabetic state, and whether IL-6 release could be reduced by weight loss. Design: Skeletal muscle metabolism was studied in men with IGT (n = 11) and compared with men with normal glucose tolerance (NGT, n = 9), matched for body mass index and age. IL-6 flux over skeletal muscle was measured with the forearm model. Eight IGT men were willing to participate in a 12-wk weight loss program and were tested again. Results: IL-6, but not C-reactive protein or TNF- receptor 1 and 2, was released by skeletal muscle. Muscle IL-6 release was higher in IGT than in NGT during fasting (IGT = 2.26 ± 1.89 vs. NGT = 0.87 ± 0.48 fmol*100 ml tissue¿1*min¿1, P = 0.04) and after a meal (mean area under the curve per minute: IGT = 3.48 ± 2.63 vs. NGT = 1.37 ± 0.75 fmol*100 ml tissue¿1*min¿1; P = 0.03). In the IGT men, body weight loss resulted in a decrease of postprandial IL-6 release from skeletal muscle (¿52%; P = 0.04), reaching levels of the obese, NGT controls. Conclusion: The present data suggest that a high-fat meal can evoke IL-6 release from muscle and that the IL-6 release is a consequence rather than a cause of the obese, insulin-resistant, and/or IGT state

Total forearm blood flow as an indicator of skeletal muscle blood flow: effect of subcutaneous adipose tissue blood flow

Total forearm blood flow as an indicator of skeletal muscle blood flow: effect of subcutaneous adipose tissue blood flow. Blaak EE, van Baak MA, Kemerink GJ, Pakbiers MT, Heidendal GA, Saris WH. Department of Human Biology, University of Limburg, Maastricht, The Netherlands. 1. In studying forearm skeletal muscle substrate exchange, an often applied method for estimating skeletal muscle blood flow is strain gauge plethysmography. A disadvantage of this method is that it only measures total blood flow through a segment of forearm and not the flow through the individual parts such as skin, adipose tissue and muscle. 2. In the present study the contribution of forearm subcutaneous adipose tissue blood flow to total forearm blood flow was evaluated in lean (% body fat 17.0 +/- 2.2) and obese males (% body fat 30.9 +/- 1.6) during rest and during infusion of the non-selective beta-agonist isoprenaline. Measurements were obtained of body composition (hydrostatic weighing), forearm composition (magnetic resonance imaging) and of total forearm (venous occlusion plethysmography), skin (skin blood flow, laser Doppler), and subcutaneous adipose tissue blood flow (133Xe washout technique). 3. The absolute forearm area and the relative amount of fat (% of forearm area) were significantly higher in obese as compared to lean subjects, whereas the relative amounts of muscle and skin were similar. 4. During rest, the percentage contribution of adipose tissue blood flow to total forearm blood flow was significantly higher in lean compared with obese subjects (19 vs 12%, P < 0.05), whereas there were no differences in percentage contribution between both groups during isoprenaline infusion (10 vs 13%). Furthermore, the contribution of adipose tissue blood flow to total forearm blood flow was significantly lower during isoprenaline infusion than during rest in lean subjects (P < 0.05), whereas in the obese this value was similar during rest and during isoprenaline infusion.(ABSTRACT TRUNCATED AT 250 WORDS