A fenugreek seed extract selectively reduces spontaneous fat consumption in healthy volunteers.

PURPOSE: Fenugreek seeds (Trigonella foenum-graecum L.) are an old herbal remedy used to treat metabolic and nutritive dysfunctions. They have been shown to modulate feeding behaviour in animals, but strong clinical data are lacking. The aim of this study was to investigate the effects of a repeated administration of a fenugreek seed extract on energy intake and eating behaviour in healthy human volunteers. METHODS: Twelve healthy male volunteers completed a double-blind randomized placebo-controlled three-period cross-over trial of two different doses of a fenugreek seed extract (588 and 1176 mg). The three 14-day treatment periods were separated by a 14-day washout period. The main endpoints were energy intake, assessed in volunteers under normal ambulatory and free-living conditions by a 3-day detailed dietary record and during a meal test, weight, fasting glucose level, insulin and lipid profile, visual analogue scale scores of appetite/satiety and blood glucose and insulin levels measured repeatedly after a standardized breakfast. RESULTS: Daily fat consumption was significantly decreased by the higher dose of fenugreek seed extract [3.73 vs. 4.51 MJ day(-1), -17.3% vs. placebo, 95% confidence interval (CI) -1.51 to -0.05, n = 12, P = 0.038]. This specific reduction tended to lower the total energy intake (9.97 vs. 11.29 MJ day(-1), -11.7% vs. placebo, 95% CI -2.91 to 0.26, n = 12, P = 0.094). No significant effect was observed on the other nutrients or other endpoints. CONCLUSIONS: The repeated administration of a fenugreek seed extract specifically decreases dietary fat consumption in humans which, given the traditional use of the plant, constitutes a novel result.

Assessment of single-dose benzodiazepines on insulin secretion, insulin sensitivity and glucose effectiveness in healthy volunteers: a double-blind, placebo-controlled, randomized cross-over trial [ISRCTN08745124].

BACKGROUND: The present study aimed at investigating in healthy volunteers the effects of diazepam and clonazepam on beta-cell function, insulin sensitivity and glucose effectiveness based on the frequently sampled intravenous (0.5 gkg-1) glucose tolerance test with minimal-model analysis. METHODS: The study was designed as a double-blind, placebo-controlled, cross-over clinical trial. Diazepam (10 mg) and clonazepam (1 mg) were infused during 30 min to 15 male subjects with a mean age of 22 years (range: 20-29), after informed consent was given. Benzodiazepines were assayed by capillary gas chromatography with electron capture, insulin by radioimmunoassay and glucose by the enzymatic glucose oxidase method. RESULTS: Both benzodiazepines induced significant psychotropic effects. The acute insulin responses (AIR) were significantly and negatively correlated with the clonazepam plasma concentrations (r = -0.609, P < 0.05, n = 14). However, the mean AIR was not significantly different between the benzodiazepine-treated subjects and the controls. In addition, the parameters of glucose assimilation were significantly decreased as compared with placebo in the subgroup of 7 subjects with plasma clonazepam concentrations higher than 6.0 ng ml-1 (median and lower limit of effective therapeutic concentrations): 1.37 +/- 0.3 versus 2.84 +/- 0.60 x 10(-2)min-1 (P = 0.028) for the coefficient of glucose tolerance (Kg), 2.18 +/- 0.29 versus 3.71 +/- 0.89 x 10(-4)microUml-1min-1 (P = 0.018) for insulin sensitivity (Si) and 1.80 +/- 0.39 versus 3.59 +/- 0.71 x 10(-2)min-1 (P = 0.028) for glucose effectiveness at basal insulin (Sg). These parameters were not significantly modified when diazepam was administered; plasma levels of this drug however, were below the effective therapeutic concentrations (300 ng ml-1) from min 15 after the end of the perfusion. CONCLUSION: The present results suggest that a benzodiazepine, in particular clonazepam, may alter insulin secretion and insulin sensitivity after a single administration in healthy volunteers.

Effects of oral monosodium (L)-glutamate on insulin secretion and glucose tolerance in healthy volunteers.

AIMS: To investigate the effects of glutamate on insulin secretion and glucose tolerance in humans. METHODS: Monosodium (L)-glutamate (10 g) was given orally in a double-blind placebo-controlled cross-over study to 18 healthy volunteers, aged 19-28 years, with an oral (75 g) glucose load. RESULTS: The 75 min insulin response (AUC(0,75 min)), up to tmax of glutamate kinetics, was significantly correlated with the AUC(0,75 min) of glutamate concentrations (r=0.485, P=0.049). Glucose tolerance was not affected. CONCLUSIONS: Oral (L)-glutamate enhances glucose-induced insulin secretion in healthy volunteers in a concentration-dependent manner.