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Biomedical subjects

A Astrup

Publications and source records attributed to A Astrup.

At least 19 recordsLinked to original sources
PubMed1992

[Over-the-counter weight-reducing preparations].

This report deals with over-the-counter products sold currently in Denmark for weight reduction. Only oral products (alternative medications and food supplements) are included. The report includes 35 such products. The aims of the report are to provide a common, factual basis for the debate about weight-reduction products and to present proposals for regulations that improve the conditions for patients and health professionals to make their choice of the optimal products. Current laws and administrative regulations are found to be complicated, obscure and inadequate. For most products, documentation for efficacy and safety is inadequate and health hazards are probable using several of the products. It is recommended 1) that obesity should be considered as a disease also in a legal/administrative context, 2) that an effective and objective registration of side-effects to alternative medication and food supplements is established, 3) that these products are tested for efficacy and safety before being marketed, 4) that the entire product information is made easily accessible, 5) that products without any documented effect are clearly labelled with this information and 6) that weight loss products involving health hazards are excluded from the market.

Denmark↗
PubMed1992

Metabolic changes during treatment with valproate in humans: implication for untoward weight gain.

This study was initiated to elucidate the mechanisms behind valproate-induced weight gain. Eight patients with epilepsy were studied with identical examination programs before and during the end of the first month of treatment with sodium valproate (VPA). The measurements included registration of food intake, indirect calorimetry, and determination of pancreatic and thyroid hormones, catecholamines, albumin, electrolytes, glycerol, and free fatty acids. Measurements were performed both at the basal condition and during a 3-hour oral glucose tolerance test (OGTT). After the start of VPA treatment, the mean levels during the OGTT of plasma glucose and catecholamines were significantly decreased by 7% and 25%, respectively (P less than .05). The mean ratio of insulin to glucagon decreased by 37% (P less than .01). During the glucose load, the decreases in free fatty acids were less pronounced after the start of VPA treatment, whereas the mean levels of glycerol were found to be unchanged. We detected no differences between the two periods with regard to total energy intake or macronutrient selection, energy expenditure, or thyroid hormones. As VPA is known to affect the concentration of carnitine in humans, it is hypothesized that a possible VPA-induced deficiency of the beta-oxidation of fatty acids is important for the development of obesity in epileptic patients in long-term treatment with VPA, but changes in catecholamines or other hormones might also be of importance.

Adult↗
PubMed1992

The effect of ephedrine/caffeine mixture on energy expenditure and body composition in obese women.

Treatment with beta 2-agonists promotes fat loss and muscle growth in numerous species, but human studies are lacking. We studied the effect of a compound with beta 2-agonistic properties (ephedrine 20 mg/caffeine 200 mg [E + C]). Fourteen obese women were treated with a 4.2-MJ/d diet and either E + C or placebo (P) three times per day for 8 weeks in a double-blind study. Weight-loss was not different in the groups, but the E + C group lost 4.5 kg more body fat and 2.8 kg less fat-free mass (FFM). The decrease in 24-hour energy expenditure (EE) seen in the P group was 10% at day 1 and 13% at day 56, but was only 7% and 8% in the treated group (P = .044). The higher EE in the E +C group was entirely covered by fat oxidation. These findings provide evidence that promotion of fat loss and preservation of FFM during weight reduction may also be achieved pharmacologically in humans.

Body Composition↗
PubMed1992

Pharmacology of thermogenic drugs.

Thermogenic combinations of ephedrine with caffeine and newer selective beta 3-agonists are being assessed for the treatment of obesity. The actions of beta-agonists may be multifaceted, with acute stimulation of thermogenic mechanisms in various tissues. During chronic treatment recruitment of brown fat may occur and hypertrophy of skeletal muscle may occur and simultaneously increase lean body tissue and reduce fat mass by stimulation of lipolysis and energy expenditure. The weight-reducing effect of an ephedrine-caffeine combination was superior to placebo treatment during 24 wk of energy restriction in obese women, whereas caffeine and ephedrine separately had no effect. In a second study it was found that ephedrine-caffeine compared with placebo preserved fat-free mass and enhanced fat loss, which could be accounted for both by anorexia (75%) and by increased thermogenesis (25%). The ephedrine-caffeine compound seems useful for the treatment of obesity and may serve as reference in the clinical assessment of new beta-agonists.

Adrenergic beta-Agonists↗
PubMed1992

A 24-h energy expenditure study on reduced-obese and nonobese women: effect of beta-blockade.

Twenty-four-hour energy expenditure (EE) and substrate oxidation rates were studied in a respiration chamber in 15 reduced-obese (BMI = 24.7) and 8 nonobese (BMI = 20.1) women. Two experiments were performed, one in which beta-blockade was introduced by propranolol and one with placebo. When adjusted for differences in fat-free mass, no difference in 24-h EE was found between the reduced-obese and nonobese groups in placebo experiments. Propranolol reduced 24-h EE by 2.7% in the reduced-obese group whereas no reduction was seen in the nonobese group. A positive correlation was found between fasting glycerol concentration and lipid oxidation. During daytime, lipid oxidation was reduced and carbohydrate oxidation increased by propranolol only in the nonobese subjects. Propranolol reduced fasting glycerol and free fatty acid concentrations in both groups. Beta-blockade seems to have little effect on sedentary 24-h EE but may have a suppressing effect on lipid combustion.

Adult↗
PubMed1992

24-hour energy expenditure and sympathetic activity in postobese women consuming a high-carbohydrate diet.

It has been suggested that the energy expenditure (EE) of formerly obese subjects (postobese) is highly susceptible to the dietary carbohydrate content and that a high dietary carbohydrate-to-fat ratio may increase their 24-h EE. We studied eight obese women before and after weight normalization (postobese state) and compared them with eight matched controls. Twenty-four hour EE, substrate oxidations, and 24-h heart rate were measured in respiratory chambers on a fixed physical program, while the postobese and controls were in macronutrient balance on a high-carbohydrate diet. Mean 24-h EE decreased from the obese to the postobese state (P less than 0.01), but it remained higher in the postobese women than in the controls (8,292 +/- 153 vs. 7,646 +/- 190 kJ/day, P = 0.01). The higher EE in the postobese group was entirely covered by a 22% higher carbohydrate oxidation (P = 0.006). The mean 24-h heart rate, as measured by telemetry, was also higher in the postobese group than in the control group (74 vs. 66 beats/min, P less than 0.03). Plasma norepinephrine (NE) concentrations were greater by 50% in the postobese as compared with the controls (P = 0.004), and differences in plasma NE concentrations entirely accounted for the group difference in 24-h EE and heart rate between postobese and controls, as analyzed by stepwise regression analysis. We conclude that postobese women on a high-carbohydrate-low-fat diet have an enhanced sympathetic nervous system activity, which is responsible for the higher 24-h EE and heart rate. These findings may have implications for understanding the pathophysiology and for the treatment of obesity.

Adult↗
PubMed1992

Effect of moderate cold exposure on 24-h energy expenditure: similar response in postobese and nonobese women.

Twenty-four-hour energy expenditure (EE) and substrate oxidation rates were measured two times in eight postobese women and eight matched controls. On one occasion the subjects were exposed to a room temperature of 16 degrees C, on the other to 24 degrees C. Cold exposure elicited a 2% increment in 24-h EE (P < 0.05), with similar response in the two groups. The slight increase in EE was entirely covered by an enhanced carbohydrate oxidation rate. Fasting plasma norepinephrine (NE) increased from 0.74 +/- 0.08 to 1.29 +/- 0.21 nmol/l under cold exposure (P < 0.05), with no group difference. The cold-induced increase in 24-h EE was positively correlated to the increase in NE concentration (r2 = 0.41, P = 0.01). Sleeping EE was found to be 5% lower in the postobese women than in the controls (P = 0.04). The postobese group also had higher 24-h nonprotein respiratory quotient than the control group (P = 0.04), which was due to a 26% lower lipid-to-carbohydrate oxidation ratio. The study demonstrates that the thermogenic response to cold is normal in women susceptible to obesity, but it supports previous reports of a slightly lower basal EE and lower lipid-to-carbohydrate oxidation ratio in postobese subjects.

Adult↗
PubMed1992

The contribution of body composition, substrates, and hormones to the variability in energy expenditure and substrate utilization in premenopausal women.

Twenty-four-hour energy expenditure and substrate use were measured by indirect calorimetry in respiration chambers on a fixed physical program and related to body composition and plasma concentrations of various substrates and thermogenic hormones. Fifty premenopausal women with a wide range of body weight were examined in the follicular menstrual phase under weight stable conditions. Most of the variance in the sleeping energy expenditure (82%) was accounted for by two covariates, lean body mass (75%, P less than 0.0001), and fat mass (7%, P less than 0.0001). An additional 6% of the variance in sleeping energy expenditure was accounted for by plasma androstenedione concentration (4%, P = 0.0005) and by free T3 index (2%, P = 0.03). Thus physiological variation among individuals in plasma androstenedione concentration may result in a difference in energy expenditure of 908 kJ/day and the corresponding variation in free T3 index may result in a difference between individuals of 594 kJ/day. Fifty four percent of the variation in carbohydrate oxidation rates was accounted for by 24-h energy balance, and by plasma concentrations of insulin, nonesterified fatty acids, and estradiol. Waist circumference, plasma nonesterified fatty acids, and estradiol concentrations explained 49% of the variance in 24-h lipid oxidation. An obese subgroup of women (n = 27) had significantly higher 24-h energy expenditure, lipid, and carbohydrate oxidation rates than an age-matched normal weight group (n = 16), but the entire group difference in energy expenditure was explained by differences in body composition. We conclude that physiological variations in plasma androstenedione and T3 concentrations contribute to the interindividual variance in energy expenditure of women, and their role is not different in obese women. A positive energy balance and increased insulin action may be mediators of the higher carbohydrate oxidation in obesity, whereas an increased substrate availability seems to bring about the increased lipid oxidation.

Adolescent↗
PubMed1992

Dexfenfluramine as adjuvant to a low-calorie formula diet in the treatment of obesity: a randomized clinical trial.

Dexfenfluramine (dF) was compared to placebo as adjuvant to a very energy-restricted diet (1.6-4.2 MJ/24 h). The diet was continued as long as possible or until a satisfactory weight loss had been achieved, and dietary efforts were continued throughout the study. Of the 37 females and five males included, 71 per cent could be followed up for 12 months. Initial BMI ranged from 28 to 54 kg/m2. The lowest body weight was reached 1 month earlier in the dF group (P = 0.037). Throughout the study, the reduction of excess weight (REW) was greater in dF patients (P less than 0.05 only at 4 and 6 months). At 6 months, excess weight had declined by 15 per cent more in the dF group than in the placebo group (95 per cent confidence limits of the median being 1-31 per cent). Between 6 and 12 months, both groups regained weight significantly, the rates of regain differing only insignificantly. At 12 months, excess weight showed a net decrease of only 8 per cent more in the dF group than in the placebo group (95 per cent confidence limits being -7 to +24 per cent). Therefore, REW showed no significant group difference after 12 months. Type of obesity (android or gynoid) as determined by waist to hip ratio had no significant impact on either weight loss, REW, reductions of waist and hip circumferences, or on waist to hip ratio changes. S-alkaline phosphatases and s-uric acid declined significantly in the dF group only. Side-effects were all mild and their prevalence showed no group difference.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The effect and safety of an ephedrine/caffeine compound compared to ephedrine, caffeine and placebo in obese subjects on an energy restricted diet. A double blind trial.

The sympathomimetic agent ephedrine has potent thermogenic and anti-obesity properties in rodents. The effect is markedly enhanced by caffeine, while caffeine given alone has no effect. This study was undertaken to find out if a similar weight reducing synergism between ephedrine and caffeine is present in obese patients. In a randomized, placebo-controlled, double blind study, 180 obese patients were treated by diet (4.2 MJ/day) and either an ephedrine/caffeine combination (20mg/200mg), ephedrine (20 mg), caffeine (200 mg) or placebo three times a day for 24 weeks. Withdrawals were distributed equally in the four groups, and 141 patients completed the trial. Mean weight losses was significantly greater with the combination than with placebo from week 8 to week 24 (ephedrine/caffeine, 16.6 +/- 6.8 kg vs. placebo, 13.2 +/- 6.6 kg (mean +/- s.d.), P = 0.0015). Weight loss in both the ephedrine and the caffeine groups was similar to that of the placebo group. Side effects (tremor, insomnia and dizziness) were transient and after eight weeks of treatment they had reached placebo levels. Systolic and diastolic blood pressure fell similarly in all four groups. We conclude, that in analogy with animal studies, the ephedrine/caffeine combination is effective, while caffeine and ephedrine separately are ineffective for the treatment of human obesity.

Administration, Oral↗
PubMed1992

Three months aerobic training fails to affect 24-hour energy expenditure in weight-stable, post-obese women.

Sedentary 24 h energy expenditure (EE) in seven reduced-obese pre-menopausal women was measured in a respiration chamber before and after a three month aerobic training period. Six of the seven women showed a higher VO2max after the training period, while resting heart rate and blood pressure decreased significantly. No significant effects of training were seen in daytime, sleeping or total 24 h EE. However, change in daytime EE was positively correlated to the change in VO2max. Sleeping and 24 h respiratory quotients were slightly increased after the training period. A negative correlation was found between the change in VO2max and the change in fasting FFA. Change in postprandial glucose concentration was also negatively correlated to change in VO2max. Satiety measured 135 min after lunch was decreased after the training period. It is concluded that the moderate physical training programme was not sufficient to obtain a substantial elevation of sedentary 24 h EE.

Adult↗
PubMed1992

Obesity: an inherited metabolic deficiency in the control of macronutrient balance?

It has generally been assumed that the body is 'energy blind' and calories from all three macronutrients contribute with the same value to energy balance. There is, however, accumulating evidence to suggest that during ad-libitum conditions energy balance is achieved by a separate regulation of carbohydrate, fat and protein balances. Regulation of carbohydrate balance has the highest priority in the hierarchy, which is appropriate because the limited glycogen stores are only capable of covering the carbohydrate oxidation for a few days. Due to the higher satiating power of carbohydrate and protein compared with fat, a reduction in the dietary fat/carbohydrate ratio produces a negative fat balance in normal subjects consuming the diet ad libitum, while an increase in dietary fat/carbohydrate ratio results in a positive fat balance and weight gain. Subjects with a genetically determined predisposition to obesity become obese when they are exposed to a particular range of environmental conditions. The available knowledge suggests that the genetic propensity to weight gain is caused by a susceptibility to dietary fat due to an impaired capacity to increase their lipid/carbohydrate oxidation when fed a high-fat/low-carbohydrate diet. This in turn promotes lipid storage, depletion of carbohydrate stores and increases appetite. By enlarging the fat stores, the accompanying insulin resistance and higher levels of circulating non-esterified fatty acids increase lipid oxidation until it is commensurate with the dietary fat intake. The development of obesity may therefore be viewed as a regulatory mechanism by which the impaired lipid oxidation rate is raised to match a high fat intake. However, by decreasing the dietary ratio of fat to carbohydrate, macronutrient balance may be achieved with a high energy expenditure and a normal body composition. The results support current dietary recommendations, but with less emphasis on carbohydrate source, and they are also applicable for the prevention and treatment of obesity.

Dietary Fats↗