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Biomedical subjects

A Astrup

Publications and source records attributed to A Astrup.

At least 73 records · Page 4Linked to original sources
PubMed2000

Randomized controlled trial of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates on body weight and blood lipids: the CARMEN study. The Carbohydrate Ratio Management in European National diets.

OBJECTIVE: To investigate the long-term effects of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates. DESIGN: Randomized controlled multicentre trial (CARMEN), in which subjects were allocated for 6 months either to a seasonal control group (no intervention) or to one of three experimental groups: a control diet group (dietary intervention typical of the average national intake); a low-fat high simple carbohydrate group; or a low-fat high complex carbohydrate group. SUBJECTS: Three hundred and ninety eight moderately obese adults. MEASUREMENTS: The change in body weight was the primary outcome; changes in body composition and blood lipids were secondary outcomes. RESULTS: Body weight loss in the low-fat high simple carbohydrate and low-fat high complex carbohydrate groups was 0.9 kg (P < 0.05) and 1.8 kg (P < 0.001), while the control diet and seasonal control groups gained weight (0.8 and 0.1 kg, NS). Fat mass changed by -1.3kg (P< 0.01), -1.8kg (P< 0.001) and +0.6kg (NS) in the low-fat high simple carbohydrate, low-fat high complex carbohydrate and control diet groups, respectively. Changes in blood lipids did not differ significantly between the dietary treatment groups. CONCLUSION: Our findings suggest that reduction of fat intake results in a modest but significant reduction in body weight and body fatness. The concomitant increase in either simple or complex carbohydrates did not indicate significant differences in weight change. No adverse effects on blood lipids were observed. These findings underline the importance of this dietary change and its potential impact on the public health implications of obesity.

Adult↗
PubMed2000

Effects of the two beta3-agonists, ZD7114 and ZD2079 on 24 hour energy expenditure and respiratory quotient in obese subjects.

OBJECTIVE: To analyze the effect of two different beta3-adrenoceptor agonists, ZD7114 and ZD2079 on 24h energy expenditure (EE) and substrate oxidations in obese weight-stable subjects. DESIGN: Measurements of 24 h EE in a respiration chamber, before and after 14 days of treatment with one of the two beta3-agonists or placebo during weight maintenance. SUBJECTS: ZD7114 study: 7 male and 15 female subjects, body mass index (BMI) 28-39 kg/m2, age 27-64 y; ZD2079 study: 10 male and 7 female subjects, BMI 27-39 kg/m2, age 31-60 y. MEASUREMENTS: EE was measured by indirect calorimetry, spontaneous physical activity (SPA) assessed by microwave radar, and 24 h heart rate was registered by telemetry. Serum potassium was measured to test for possible beta2-adrenoceptor activity. RESULTS: No effects of ZD7114 were found on tested parameters whereas there was a trend for a stimulatory effect of ZD2079 on 24h EE (day 14-pretreatment; ZD2079 vs placebo: 0.4 +/- 1.1 vs -2.0 +/- 0.4%, P = 0.06) and on SPA (day 14-pretreatment; ZD2079 vs placebo: 3.4 +/- 4.5 vs -7.7 +/- 2.7%, P = 0.05). However, average 24 h heart rate decreased from 77.5 +/- 3.2 to 73.8 +/- 2.6 min(-1) from pre-treatment to day 14 with placebo but remained the same with ZD2079 (P = 0.03). The latter suggests some beta1-adrenoceptor activity of the compound. CONCLUSION: The lack of thermogenic response with ZD7114 and the very small and questionable response with ZD2079 probably demonstrate a lack of consistency between species in the responsiveness to beta3-stimulation or a diversity in structure of the beta3 receptor since both compounds have proven markedly selective thermogenic beta3-properties in rodents.

Adrenergic beta-3 Receptor Agonists↗
PubMed2000

The role of low-fat diets in body weight control: a meta-analysis of ad libitum dietary intervention studies.

OBJECTIVES: Low-fat high-carbohydrate diets are recommended to prevent weight gain in normal weight subjects and reduce body weight in overweight and obese. However, their efficacy is controversial. We evaluated the efficacy of ad libitum low-fat diets in reducing body weight in non-diabetic individuals from the results of intervention trials. DESIGN: Studies were identified from a computerized search of the Medline database from January 1966 to July 1999 and other sources. Inclusion criteria were: controlled trials lasting more than 2 months comparing ad libitum low-fat diets as the sole intervention with a control group consuming habitual diet or a medium-fat diet ad libitum. MAIN OUTCOME MEASURES: Differences in changes in dietary fat intake, energy intake and body weight. Weighted mean differences for continuous data and 95% confidence intervals (CIs) were calculated. RESULTS: Two authors independently selected the studies meeting the inclusion criteria and extracted data from 16 trials (duration of 2-12 months) with 19 intervention groups, enrolling 1910 individuals. Fourteen were randomized. Weight loss was not the primary aim in 11 studies. Before the interventions the mean proportions of dietary energy from fat in the studies were 37.7% (95% CI, 36.9-38.5) in the low-fat groups, and 37.4% (36.4-38.4) in the control groups. The low-fat intervention produced a mean fat reduction of 10.2% (8.1-12.3). Low-fat intervention groups showed a greater weight loss than control groups (3.2 kg, 95% confidence interval 1.9-4.5 kg; P < 0.0001), and a greater reduction in energy intake (1 138 kJ/day, 95% confidence interval 564-1712 kJ/day, P = 0.002). Having a body weight 10 kg higher than the average pre-treatment body weight was associated with a 2.6 +/- 0.8 kg (P = 0.011) greater difference in weight loss. CONCLUSION: A reduction in dietary fat without intentional restriction of energy intake causes weight loss, which is more substantial in heavier subjects.

Body Weight↗
PubMed2000

The sympathetic nervous system and obesity: role in aetiology and treatment.

The sympathetic nervous system (SNS) is an important component of the autonomic nervous system, and thus plays a major role in the maintenance of homeostasis. The SNS is of particular importance in the control of the cardiovascular system and of a number of metabolic processes. Alterations in SNS effects on metabolism have been implicated in the development and maintenance of obesity, and the SNS is a potential therapeutic target in the treatment of obesity. This review provides an overview of the anatomical and physiological aspects of the SNS, before considering the evidence showing a role for the SNS in the development or treatment of obesity.

Basal Metabolism↗
PubMed2000

Lessons from obesity management programmes: greater initial weight loss improves long-term maintenance.

It is a common belief that weight loss achieved at a slow rate is better preserved than if the weight is lost more rapidly. However, the literature shows that initial weight loss is positively, not negatively, related to long-term weight maintenance. There is evidence from randomised intervention trials to support that a greater initial weight loss induced without changes in lifestyle (e.g. liquid formula diets or anorectic drugs) improves long-term weight maintenance, providing it is followed by a 1-2 years integrated weight maintenance programme consisting of lifestyle interventions involving dietary change, nutritional education, behaviour therapy and increased physical activity. In conclusion, we find evidence to suggest that a greater initial weight loss as the first step of a weight management programme may result in improved sustained weight maintenance.

Appetite Depressants↗
PubMed2000

Redefining type 2 diabetes: 'diabesity' or 'obesity dependent diabetes mellitus'?

Type 2 diabetes is considered by diabetes physicians as a complex and heterogeneous disease with a poorly understood aetiology, apart from the fact that there is a strong genetic propensity that becomes overt when exposed to a typical Western lifestyle. Our clinical targets are now moving from controlling the disease to preventing it. Do we need to await more research on the aetiology and pathophysiology before establishing a preventive strategy? No, the pathophysiology may be poorly understood, but there is now solid evidence that type 2 diabetes is a disease of fatness. New, controlled, clinical trials show that as little as 5% weight loss is sufficient to prevent most obese subjects with impaired glucose tolerance developing type 2 diabetes. Since type 2 diabetes is obesity dependent, and obesity is the main aetiogical cause of type 2 diabetes, we propose the term 'diabesity' should be adopted.

Adipose Tissue↗
PubMed2000

Ad libitum intake of low-fat diets rich in either starchy foods or sucrose: effects on blood lipids, factor VII coagulant activity, and fibrinogen.

People are advised to reduce their intake of saturated fat and replace it by carbohydrate to avoid coronary heart disease. It is unknown whether sucrose and starchy foods, two major sources of carbohydrates, have similar effects on cardiovascular risk markers if incorporated as a replacement for saturated fat into diets eaten ad libitum. We served 20 healthy, normal-weight women aged 21 to 52 years three strictly controlled diets ad libitum: FAT, high in total fat (46% of total energy [E%]) and saturated fat (21 E%); STARCH, high in total carbohydrates (59 E%) and low in sucrose (2.5 E%); and SUCROSE, high in total carbohydrates (59 E%) and sucrose (23.2 E%). The diets were eaten in randomized order for a period of 2 weeks. Blood lipids, factor VII coagulant activity (FVIIc), and fibrinogen concentrations were measured with subjects in the fasted state (9:45 AM) and the postabsorptive state (6:00 PM). STARCH was associated with lower total cholesterol (mean difference, 0.34 mmol/L; 95% confidence interval [CI], 0.18 to 0.50), low-density lipoprotein (LDL) cholesterol (0.25 mmol/L; 95% CI, 0.13 to 0.37), fasting triglycerides (0.15 mmol/L; 95% CI, 0.07 to 0.23), nonfasting triglycerides (0.44 mmol/L; 95% CI, 0.30 to 0.58), and nonfasting FVIIc (9.8%; 95% CI, 3.8 to 15.8) than SUCROSE. Compared with FAT, STARCH resulted in a desirable decrease of LDL cholesterol and nonfasting FVIIc. STARCH was also associated with a minor weight loss (0.7 kg) that was not found on the other 2 diets. We conclude that starchy foods with a natural content of dietary fiber can be recommended as substitutes for saturated fat in the dietary prevention of coronary heart disease. According to the present short-term findings in healthy females, substitution with sucrose is not advisable.

Adult↗
PubMed2000

D-tagatose, a stereoisomer of D-fructose, increases blood uric acid concentration.

D-Fructose has been found to increase uric acid production by accelerating the degradation of purine nucleotides, probably due to hepatocellular depletion of inorganic phosphate (Pi) by an accumulation of ketohexose-1-phosphate. The hyperuricemic effect of D-tagatose, a stereoisomer of D-fructose, may be greater than that of D-fructose, as the subsequent degradation of D-tagatose-1-phosphate is slower than the degradation of D-fructose-1-phosphate. We tested the effect of 30 g oral D-tagatose versus D-fructose on plasma uric acid and other metabolic parameters in 8 male subjects by a double-blind crossover design. Both the peak concentration and 4-hour area under the curve (AUC) of serum uric acid were significantly higher after D-tagatose compared with either 30 g D-fructose or plain water. The decline in serum Pi concentration was greater at 50 minutes after D-tagatose versus D-fructose. The thermogenic and lactacidemic responses to D-tagatose were blunted compared with D-fructose. D-Tagatose attenuated the glycemic and insulinemic responses to a meal that was consumed 255 minutes after its administration. Moreover, both fructose and D-tagatose increased plasma concentrations of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1). The metabolic effects of D-tagatose occurred despite its putative poor absorption.

Administration, Oral↗
PubMed2000

Effects of oral D-tagatose, a stereoisomer of D-fructose, on liver metabolism in man as examined by 31P-magnetic resonance spectroscopy.

D-tagatose, which is a stereoisomer of D-fructose, is phosphorylated to D-tagatose-1-phosphate by fructokinase in the liver. Because of a slow degradation rate of D-tagatose-1-phosphate, this substance may accumulate, and ingested D-tagatose may therefore cause a longer lasting reduction in inorganic phosphate (Pi) and adenosine triphosphate (ATP) levels in the liver compared with D-fructose. Similar to what is seen in patients with hereditary fructose intolerance, this may increase purine nucleotide degradation and thereby increase uric acid production. The effect of 30 g D-tagatose or D-fructose administered orally on ketohexose-1-phosphates, ATP, and Pi levels in the liver was studied by 31P-magnetic resonance spectroscopy (PMRS) in 5 young male volunteers. Blood and urine were collected to detect a possible increased uric acid production. A peak at 5.2 ppm assigned as D-tagatose-1-phosphate equivalent to about 1 mmol/L was found in the spectrum within 30 minutes after D-tagatose was administered in all subjects. Concomitantly, ATP was reduced by about 12% (P < .05). Both effects had vanished after 150 minutes. Serum uric acid concentration was increased by 17% 50 minutes after D-tagatose (P < .05) and did not reach baseline level when the experiment was terminated 230 minutes after the load. Although renal fractional extraction of uric acid decreased by approximately 12%, this could not explain the acute hyperuricemic effect of D-tagatose. No changes in 31PMRS spectra or serum uric acid concentration were found after D-fructose. These results suggest that a moderate intake of D-tagatose may affect liver metabolism by phosphate trapping despite the fact that the sugar may only be incompletely absorbed in the gut.

Adenosine Triphosphate↗
PubMed2000

Effect of fat-reduced diets on 24-h energy expenditure: comparisons between animal protein, vegetable protein, and carbohydrate.

BACKGROUND: Single-meal tests have shown that protein has greater thermogenic and satiating effects than does carbohydrate, which may be relevant for the prevention and treatment of obesity if these effects can be maintained over 24 h. OBJECTIVE: The effects of pork-meat protein, soy protein, and carbohydrate on 24-h energy expenditure were compared. DESIGN: Twelve young, healthy, overweight and mildly obese [body mass index (in kg/m(2)): 26-32] nonsmoking men participated in a randomized, single-blind, 3-way crossover study lasting 4 d. The intervention had a 1-10-wk washout period. The 3 isoenergetic intervention diets were as follows: pork diet (29% of energy as fat and 29% as protein, mainly from pork meat), soy diet (29% of energy as fat and 28% as protein, mainly from soy), and carbohydrate diet (28% of energy as fat and 11% as protein). Twenty-four-hour energy expenditure was measured in a respiratory chamber at baseline and on day 4 of each intervention period. RESULTS: Twenty-four-hour energy expenditure was higher with the pork than with the soy (248 kJ/d, 1.9%; P: = 0.05) or carbohydrate (492 kJ/d, 3.9%; P: < 0.0001) diet and higher with the soy than with the carbohydrate (244 kJ/d, 1.9%; P: < 0.05) diet. However, because of a higher satiating effect, energy intake was 10-15% lower during the chamber stay than at baseline (P: > 0.05) with all 3 diets. The differences in energy expenditure remained unchanged after adjustment for differences in 24-h energy balance. CONCLUSIONS: Substitution of carbohydrate with 17-18% of energy as either pork-meat or soy protein produced a 3% higher 24-h energy expenditure. The animal protein in pork meat produced a 2% higher 24-h energy expenditure than did the vegetable protein in soy.

Adult↗
PubMed2000

Measurements of body composition by dual-energy X-ray absorptiometry improve prediction of energy expenditure.

The prediction of energy expenditure by dual-energy X-ray absorptiometry (DXA) and bioimpedance analysis (BIA) was assessed in 35 healthy individuals of both sexes, with a mean body mass index (BMI) of 23.8 kg/m2 (range 18-33.8), and mean age of 30 years (22-40). Energy expenditure (EE) was measured under standard conditions in a respiration chamber, the total and regional body composition by DXA, and total body composition by BIA. When body composition was measured by BIA, 88.5% of the variation in 24-h EE was explained by lean body mass (LBM); this figure was increased by DXA, where total lean tissue mass (LTM) and total fat tissue mass (FTM) could account for 91.5% of the variation. Also, the prediction of resting energy expenditure (REE) was improved by DXA, from 88.1% to 89.8% (LBM vs. LTM, FTM). Measurements of regional body composition showed that trunk LTM was significantly superior as a predictor, especially of REE and sleeping EE (EE sleep), compared to the peripheral LTM; thus, the predictions of REE were 83% vs. 87% (peripheral vs. trunk), respectively; and the predictions of EE sleep were 83% vs. 89% (peripheral vs. trunk), respectively. Therefore, body composition measurements by DXA improved the prediction of EE. Trunk LTM was a superior predictor, especially of REE and EE sleep, compared to peripheral LTM. In conclusion, the present results suggest that measuring total and regional body composition by DXA can somewhat improve the prediction of EE.

Absorptiometry, Photon↗
PubMed2000

Thermogenic drugs as a strategy for treatment of obesity.

There is accumulating evidence to support the hypothesis that a low-energy-output phenotype is at high risk of weight gain and obesity, irrespective of whether this is owing to a low resting metabolic rate and/or physical inactivity. The low-energy-output phenotype is associated with impaired appetite control, which is improved if energy output is increased. This is the background for pharmacologic stimulation of energy expenditure as a tool to improve the results of obesity management. Targets are the leptin receptors, the sympathetic nervous system and its peripheral beta-adrenoceptors, selective thyroid hormone derivatives, and stimulation of the mitochondrial uncoupling proteins. Currently available compounds such as recombinant leptin, ephedrine/caffeine, and sibutramine possess thermogenic properties owing to their activation of the sympathoadrenal system. Compounds acting selectively on the human beta3-adrenoceptor are still promising tools to achieve a sustained stimulation of lipolysis and energy expenditure, and several are in the pipeline.

Adrenal Glands↗
PubMed2000

The acute effect of D-tagatose on food intake in human subjects.

A double-blind randomized crossover study was performed with nineteen normal-weight men to investigate the effect on subsequent ad libitum food intake of replacing 29 g sucrose with 29 g D-tagatose as sweetener to a breakfast meal. D-Tagatose is a malabsorbed stereoisomer of fructose with potential application as a bulk sweetener. Food intake was measured at lunch offered 4 h after the breakfast meal, during the afternoon with access to abundant snacks, and finally at a supper buffet 9 h after the breakfast. Energy intake at lunch and during the snacking period was similar after ingesting the two sugars, while it was 15% lower after ingesting D-tagatose than with sucrose at supper (P < 0.05). Gastrointestinal factors such as the osmotic effects of unabsorbed D-tagatose causing distension of the gut might have mediated the acute appetite-suppressing effect. The present paper also refers to data from a preceding study in which we observed an increased self-reported energy intake after ingestion of D-tagatose compared with sucrose which, in fact, suggests a relative hyperphagic effect of D-tagatose. However, self-reported food intake may be biased by selective under-reporting and this subsequent study with a more controlled assessment of food intake was therefore conducted. This present study did not support any hyperphagic effect of D-tagatose, but rather suggests that D-tagatose may contribute to a reduced energy intake.

Adult↗
PubMed1999

Human tolerance to a single, high dose of D-tagatose.

The addition of 29 g D-tagatose added as a sweetener to a continental breakfast was tested for the appearance of gastrointestinal side effects in a double-blind randomized cross-over study with 29 g sucrose as a control treatment. The subjects reported the side effects during 72 h following the test meal on a questionnaire grading the symptoms on a five-level scale ranging from "none" to "very strong." Although "rumbling in the stomach," "distention," "nausea," "rumbling in the gut," "flatulence, " and "diarrhea" scored significantly higher with D-tagatose, the sugar otherwise was well tolerated in most of the subjects. Two cases of vomiting after D-tagatose were recorded but in one of the cases its relation to the D-tagatose intake was questionable. Only the "distention" score remained higher with D-tagatose for more than 24 h. Nausea, vomiting, and perceived distension may be due to an osmotic effect in the small intestine of unabsorbed D-tagatose. The increased flatus is caused by D-tagatose being fermented in the large intestine. Diarrhea may be explained by osmotic effects in the colon from nondegraded D-tagatose or nonabsorbed short-chain fatty acids produced by the increased fermentation.

Adult↗
PubMed1999

Human gastrointestinal tolerance to D-tagatose.

D-Tagatose is a stereoisomer of D-fructose which is poorly absorbed in the small intestine and may, therefore, have potential as a reduced calorie bulk sweetener. However, one of the major limitations is the use of malabsorbed sugars is that their consumption may be associated with gastric discomfort. This is due to the osmotic impact of the sugar molecules remaining in the gut lumen for a prolonged period. We have performed a series of studies in which gastrointestinal symptoms have been recorded after the consumption of 29 or 30 g of D-tagatose. Nausea and diarrhea were reported with an incidence of 15.1 and 31.5%, respectively, in 73 healthy young male subjects in a screening study. Increased flatulence after D-tagatose was frequently reported in all the studies and the flatulence did not decline during a 15-day period with intake of 30 g in one dose daily. In most cases, symptoms were reported as light or moderate. However, the results suggest that 30 g taken at one time may be above the dose which should be recommended for ordinary use.

Adult↗
PubMed1999

Macronutrient balances and obesity: the role of diet and physical activity.

Observational cross-sectional and longitudinal studies suggest that a high fat diet and physical inactivity are independent risk factors for weight gain and obesity. Mechanistic and intervention studies support that fat possesses a lower satiating power than carbohydrate and protein, and a diet low in fat therefore decreases energy intake. The effect of dietary fat on energy balance is enhanced in susceptible subjects, particularly in sedentary individuals with a genetic predisposition to obesity who consume a high fat diet. Dietary carbohydrate promotes its own oxidation by an insulin-mediated stimulation of glucose oxidation. In contrast, high fat meals do not increase fat oxidation acutely. A sedentary life-style and low physical fitness cause a low muscular fat oxidation -capacity, and the consumption of a high fat diet by these individuals promotes fat storage in a synergistic fashion. Ad libitum low fat diets cause weight loss proportional to pre-treatment body weight in a dose-dependent way, i.e. weight loss is correlated positively to the reduction in dietary fat content. Increased physical activity prevents relapse after weight loss and studies have shown that those who keep up a higher level of physical activity are more successful in maintaining the reduced body weight. In conclusion, important interactions exist between genetic make up, dietary fat and physical fitness, so that a low fitness level and susceptible genes reduce muscular fat oxidation capacity which may decrease the tolerance of dietary fat. Increasing daily physical activity and reducing dietary fat content may be more effective when combined than when separate in preventing weight gain and obesity.

Diet↗