Showing papers by "Arne Astrup published in 2003"

Regulation of adiponectin by adipose tissue-derived cytokines: in vivo and in vitro investigations in humans.

Abstract: Adiponectin is an adipose tissue-specific protein that is abundantly present in the circulation and suggested to be involved in insulin sensitivity and development of atherosclerosis. Because cytok...

Association between measures of insulin sensitivity and circulating levels of interleukin-8, interleukin-6 and tumor necrosis factor-alpha. Effect of weight loss in obese men

Abstract: OBJECTIVE To study the association between anthropometric and metabolic parameters as well as the effect of weight loss on plasma levels of the adipose tissue-derived cytokines interleukin-8 (IL-8), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in abdominal obese men. SUBJECTS Nineteen obese (mean body mass index (BMI): 38.6+/-0.6 kg/m(2)) and ten lean men (mean BMI: 23.4+/-0.4 kg/m(2)) were included in the study. The obese subjects received a 4.2 MJ/day diet for 8 weeks, followed by 8 weeks on energy restriction (6.2 MJ/day) and 8 weeks on a weight-maintenance diet. MEASUREMENTS A dual energy X-ray absorptiometry (DEXA)-scan was performed to estimate body composition. Plasma levels of IL-8, IL-6 and TNF-alpha were measured by a specific ELISA method. Insulin sensitivity was assessed by the homeostasis model assessment method (HOMA). RESULTS Plasma levels of IL-8 and IL-6 were 30-40% higher in obese as compared with lean subjects (P<0.05), whereas no group difference in TNF-alpha was observed. During the intervention, obese subjects obtained a 30% reduction in fat mass (P<0.001), fasting insulin (P<0.05) and HOMA (P<0.05). Plasma levels of TNF-alpha and IL-6 were decreased by 25-30% (P<0.001) but IL-8 was increased by 30% (P<0.001) after weight loss. IL-8 and IL-6 were correlated with measures of insulin resistance, and changes in IL-6 but not IL-8 were correlated with the improvement in insulin sensitivity after weight loss. CONCLUSION Plasma levels of IL-8 and IL-6 were found to be increased and were correlated with measures of insulin resistance in abdominal obese male subjects. Weight loss was associated with changes in the circulating levels of IL-8, IL-6 and TNF-alpha indicating that these cytokines are influenced by weight loss.

PPARgamma agonists in the treatment of type II diabetes: is increased fatness commensurate with long-term efficacy?

Abstract: The nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARgamma) is a member of the PPAR family. The endogenous activators of all members of the PPAR family are a variety of fatty acids, which suggests that the PPARs are highly involved in lipid metabolism. In the present paper, the current understanding of the involvement of PPARgamma in adipocyte proliferation and adipose tissue formation is extensively reviewed, and it is stressed that PPARgamma seems to be a major regulator in the differentiation of adipocytes. Thiazoledinediones (TZDs) are a group of PPARgamma-agonists used in the treatment of type 2 diabetes (T2D) since 1997. They are characterized by their ability to decrease insulin resistance, and have been suggested to slow down the progression of insulin resistance. Treatment with TZD requires several weeks of treatment to decrease plasma glucose levels, but in addition they markedly decrease plasma triglycerides and free fatty acids. A major drawback of treatment with TZD is body fat gain, but some evidence suggests that the fat is redistributed in a favourable direction, that is, from visceral to subcutaneous depots. However, the effect of long-term treatment on weight gain following TZD treatment is unknown, and it may be questioned whether the use of these 'adipogenic compounds' is appropriate, considering that excess body fat is almost a prerequisite for the development of type 2 diabetes.

Sociodemographic differences in dietary habits described by food frequency questions--results from Denmark.

Abstract: Objectives: To investigate whether a modest number of food frequency questions are sufficient to describe sociodemographic differences in dietary habits, and to identify sociodemographic characteristics of subjects adhering to food-based dietary guidelines operationalised in a ‘healthy-diet index’. Design: Cross-sectional population survey. Subjects: A total of 480 men, 515 women, aged 15–90 y. Random sample of private telephone numbers drawn from regional telephone records, geographically stratified. Participation rate 62%. Methods: Computer-assisted telephone interviews, including six food frequency questions, a question on type of fat spreads used on bread, questions on seven sociodemographic variables. Results: The summary of the healthy-diet index showed that the subjects who adhered to food-based dietary guidelines (top quintile) compared to those who did not (bottom quintile) were most often women (odds ratio (OR)=6.07; confidence interval (CI): 3.91–9.43, women vs men), of older age (OR=9.72; CI: 3.02–31.31, old age vs young), highly educated (OR=3.69; CI: 1.53–8.92, high education vs low) and living in multiperson households including children (OR=4.66; CI: 2.47–8.80, multiperson household vs single household). The results also showed that gender difference in dietary habits is associated with other sociodemographic variables. Conclusions: The selected food frequency questions proved sufficient to describe sociodemographic differences in dietary habits, and this method may be a valuable supplement to traditional quantitative dietary surveys in monitoring sociodemographic changes in eating patterns. The results also underline the influence of sociodemographic status on dietary habits. Sponsorship: The Danish Nutrition Council funded the study.

No effect of physiological concentrations of glucagon-like peptide-2 on appetite and energy intake in normal weight subjects

Abstract: No effect of physiological concentrations of glucagon-like peptide-2 on appetite and energy intake in normal weight subjects †

Effects of different dietary fat types on postprandial appetite and energy expenditure

Abstract: Objective: Observational studies suggest that monounsaturated (MUFA) and trans fatty acids (TRANS) are more fattening than polyunsaturated fatty acids (PUFA). Therefore, the aim of this study was to investigate the acute effect of intake of PUFA, MUFA, or TRANS on appetite and energy expenditure (EE). Research Methods and Procedures: Three test meals were randomly given in a cross-over design to 19 overweight (BMI: 26.8 ± 0.4 kg/m2), young (25.2 ± 0.7 years) men. The fat-rich breakfasts (0.8 g fat/kg body weight, 60% energy from fat) varied only in the source of C:18-fat. EE was measured continuously in a respiration chamber, and appetite sensations were rated by visual analog scales before and every 30 minutes, for 5 hours, after the meal. After 5 hours, an ad libitum meal was served, and energy intake was registered. Sensory evaluations of all meals were given using visual analog scales. Data were analyzed by two-way ANOVA. Results: There were no differences in basal or postprandial values of appetite ratings and EE, in subsequent ad libitum energy intake, or in the sensory evaluation of the test meals among the 3 test days. Discussion: Giving acutely large amounts of MUFA, PUFA, or TRANS did not impose any differences in appetite and EE in overweight humans. However, studies with extended protocols and other subject groups are warranted to investigate the long-term effect of dietary fat quality on the regulation of energy balance and body weight.

Comparisons of leptin, incretins and body composition in obese and lean patients with hypopituitarism and healthy individuals.

Abstract: Summary objective To identify possible abnormalities specific for obesity in hypopituitary patients. study design Cross-sectional case–control study. measurements and study subjects Body composition (DEXA) and measurements of fasting plasma levels of glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptides (GLPs), insulin, C-peptide, glucose, leptin and lipids were performed in 25 hypopituitary patients (15 obese, 10 normal weight) and 26 BMI and age-matched healthy controls (16 obese, 10 normal weight). All hypopituitary patients had GH deficiency and received adequate substitution therapy on this and other deficient axes (3 ± 1). results Fasting GIP-levels were significantly higher in obese hypopituitary patients compared to lean hypopituitary patients (P < 0·01), while the fasting concentrations of GLP-1 and GLP-2 were comparable between obese and lean hypopituitary patients. The same trend was seen in obese healthy controls vs. lean controls. No differences were observed in glucose, insulin or C-peptide between the hypopituitary patients and the controls. Leptin levels were increased in obese hypopituitary patients compared to lean hypopituitary patients when adjusted for gender. At least a 2-fold higher level of leptin was observed in women compared to men in both patient groups and healthy controls. Lean female hypopituitary patients had higher leptin levels than matched controls. conclusions Fasting levels of GIP were elevated in obese substituted hypopituitary patients, while fasting concentrations of GLPs were similar. Obese hypopituitary patients had the same degree of hyperinsulinaemia, affected glucose tolerance, dyslipoproteinaemia and central obesity as obese healthy controls. Further studies are required to identify the possible biochemical reasons for obesity in patients with apparently well-substituted hypopituitarism.

Abnormal sympathoadrenal activity, but normal energy expenditure in hypopituitarism.

Abstract: In this study of 23 hypopituitary patients and 26 healthy controls, we have addressed whether the obese state of substituted hypopituitary patients is facilitated by abnormal sympathoadrenal activity or energy expenditure (EE). All patients received adequate substitution therapy including GH therapy. The investigation program included assessment of sympathoadrenal activity (urinary catecholamines), body composition (dual-energy x-ray absorptiometry), appetite sensations (visual analog scale), and EE (indirect calorimetry in respiration chamber). Twenty-four-hour urinary epinephrine adjusted for lean body mass and fat mass was significantly lower in patients compared with controls. GH and hydrocortisone were single negative predictors of urinary epinephrine. The major determinants of EE in patients were lean body mass and fat mass, explaining 96, 95, and 80% of the variance in 24-h EE, sleeping EE, and basal metabolic rate, respectively. Addition of urinary catecholamines explained another 1-4% of the variance in 24-h EE and basal metabolic rate, respectively. Lean patients exhibited significantly more hunger than obese patients and lean controls. In conclusion, hypopituitary patients have lower sympathoadrenal activity but normal EE, compared with healthy controls. This may reflect a central defect in hypopituitarism, however the possible impact of long-term GH and hydrocortisone treatment requires further attention.

Dietary fat and obesity: still an important issue

Abstract: The role of a reduction in dietary fat for weight loss and maintenance should be assessed by evidence-based principles giving most weight to randomized clinical trials. Four meta-analyses examined weight changes on ad libitum fat-reduced diets in intervention trials lasting for up to 1 year, and they all demonstrated a 3_/4 kg larger weight loss on the fat-reduced than on the normal-fat diet in normal-weight and overweight subjects. The analyses also show a dose_/response relationship, i.e. the reduction in percentage energy as fat is positively associated with weight loss. Weight loss is also positively related to initial weight: a 10% reduction in dietary fat is predicted to produce a 4_/5 kg weight loss in an individual with a body mass index of 30 kg m_2. The outcome of the meta-analysis of trials with long-term follow-up included only six studies, and none of the trials had an active intervention throughout the period. Short-term trials clearly demonstrate th at the non-fat diet components are at least as important for body-weight regulation as the fat content. Sugar in beverages is less satiating and more obesity promoting than sugar in solid foods, and replacement of energy from fat by sugar derived from sweetened beverages is not likely to produce weight loss. Protein is more satiating and thermogenic than carbohydrates, and a fat-reduced diet with a high protein content (20-25% of energy) may increase the efficacy of fat-reduced diets markedly. Whereas the glycaemic index of the carbohydrate may play a role for cardiovascular risk factors, there is very little evidence to support that low glycaemic index foods facilitate weight control. The evidence linking particular fatty acids to body fatness is weak. If anything, monounsaturated fatty acids (MUFA) may be more fattening than polyunsaturated and saturated fats, and no ad libitum dietary intervention study has shown that a normal-fat, high-MUFA diet is equivalent or superior to a low-fat diet in the prevention of weight gain and obesity. The current evidence strongly supports a diet with reduced content of fat and sugar-rich beverages, and more carbohydrates, rich in fibre and grain (whole-grain foods, fruit and vegetables) and protein (lean meat and dairy products) as the best choice for the prevention of weight gain, obesity, type 2 diabetes and cardiovascular disease. The use of a normal-fat, high-MUFA diet needs more evidence from randomized ad libitum dietary intervention trials before it can be recommended to the public. Keywords: fat-reduced diets; food pyramid; glycaemic index; low-fat diets; protein; weight loss

Is there any conclusive evidence that exercise alone reduces glucose intolerance

Abstract: Physical activity improves insulin sensitivity and glucose metabolism, although such effects are short-lasting and regular exercise is needed to sustain them. Weight loss, especially loss of visceral fat, appears to be especially important in improving metabolic function and clinical outcomes. The most important consequences of exercise are probably promotion of weight loss and prevention of weight gain. Substantial weight losses, associated with significant improvements in glycaemic control and reductions in the incidence of type 2 diabetes, have been observed in intervention studies in overweight or obese subjects. These benefits were achieved using intensive lifestyle interventions, pharmacotherapy or surgery. Thus, programmes of diet and exercise aimed at achieving control of body weight should play a central role in strategies for diabetes prevention. Br J Diabetes Vasc Dis 2003;3(suppl 1):S18‐S23