Many, but not all, of the effects of caffeine are mediated via the sympathetic nervous system. The effect of caffeine on lipid mobilization in resting conditions can be interpreted in 2 ways: lipid mobilization alone is insufficient to drive lipid oxidation, or large increments in lipid turnover result in small increments in lipid oxidation.

Calcium supplementation can be used as a means of reducing the absorbable energy value of chocolate. Supplementation with 2.25% CaCO3 had no effect on the taste of chocolate, was well tolerated by the subjects, and reduced LDL cholesterol in a short-term study.

This study describes a rapid and simple method to determine short-chain fatty acid (SCFA) concentrations and their isotopic enrichments (M(0) + 1 and M(0) + 2) in human plasma. Sample preparation involves SCFA extraction and derivatization with 1-(tert-butyldimethylsilyl)imidazole. Gas chromatography/mass spectrometry was performed using chemical ionization with ammonia as the reagent gas. Outstanding resolution, excellent linearity and good detection limits were obtained. Inter-assay and intra-assay repeatability was below 10% and 3% respectively for SCFA concentration. Inter-assay repeatability was below 5%, 4%, 6%, and 14% for isotopic enrichment determination of [1-(13)C]acetate and [1,2-(13)C(2)]acetate, [1-(13)C]propionate and [1-(13)C]butyrate respectively, with intra-assay being below 6%. Such SCFA concentrations and isotopic enrichments were determined in the plasma of rats infused with a (13)C-labeled SCFA. The turnovers of acetate, propionate and butyrate in rats were 19 micromol kg(-1) min(-1), 2.6 micromol kg(-1) min(-1), 0.3 micromol kg(-1) min(-1) respectively.

IntroductionThere has been renewed interest in mushroom medicinal properties. We studied cholesterol lowering properties of Ganoderma lucidum (Gl), a renowned medicinal species.ResultsOrganic fractions containing oxygenated lanosterol derivatives inhibited cholesterol synthesis in T9A4 hepatocytes. In hamsters, 5% Gl did not effect LDL; but decreased total cholesterol (TC) 9.8%, and HDL 11.2%. Gl (2.5 and 5%) had effects on several fecal neutral sterols and bile acids. Both Gl doses reduced hepatic microsomal ex-vivo HMG-CoA reductase activity. In minipigs, 2.5 Gl decreased TC, LDL- and HDL cholesterol 20, 27, and 18%, respectively (P < 0.05); increased fecal cholestanol and coprostanol; and decreased cholate.ConclusionsOverall, Gl has potential to reduce LDL cholesterol in vivo through various mechanisms. Next steps are to: fully characterize bioactive components in lipid soluble/insoluble fractions; evaluate bioactivity of isolated fractions; and examine human cholesterol lowering properties. Innovative new cholesterol-lowering foods and medicines containing Gl are envisioned.

Chicory roots are rich in inulin that is degraded into SCFA in the caecum and colon. Whole-body SCFA metabolism was investigated in rats during food deprivation and postprandial states. After 22 h of food deprivation, sixteen rats received an IV injection of radioactive 14 C-labelled SCFA. The volume of distribution and the fractional clearance rate of SCFA were 0·25 -0·27 litres/kg and 5·4 -5·9 %/min, respectively. The half-life in the first extracellular rapidly decaying compartment was between 0·9 and 1·4 min. After 22 h of food deprivation, another seventeen rats received a primed continuous IV infusion of 13 C-labelled SCFA for 2 h. Isotope enrichment ( 13 C) of SCFA was determined in peripheral arterial blood by MS. Peripheral acetate, propionate and butyrate turnover rates were 29, 4 and 0·3 mmol/kg per min respectively. Following 4 weeks of treatment with chicory root or control diets, eighteen fed rats received a primed continuous IV infusion of 13 C-labelled SCFA for 2 h. Intestinal degradation of dietary chicory lowered caecal pH, enhanced caecal and colonic weights, caecal SCFA concentrations and breath H 2 .The diet with chicory supplementation enhanced peripheral acetate turnover by 25 % (P¼0·017) concomitant with an increase in plasma acetate concentration. There were no changes in propionate or butyrate turnovers. In conclusion, by setting up a multi-tracer approach to simultaneously assess the turnovers of acetate, propionate and butyrate it was demonstrated that a chronic chicory-rich diet significantly increases peripheral acetate turnover but not that of propionate or butyrate in rats.Short-chain fatty acids: Chicory: Kinetics: Rats Dietary fibres are fermented in the large intestine of man by anaerobic bacteria to produce SCFA, such as acetate, propionate and butyrate, and some gases 1,2 . SCFA are found in large quantities in portal vein blood after intestinal absorption and to a lesser extent in peripheral blood. Acetate is the most prominent SCFA in peripheral blood, it is favoured by most cells of the body as an energetic substrate and its oxidation contributes to about 7 % whole-body resting energy expenditure in man 3 . All SCFA contribute to gut health and maintenance 2,4 and may provide further benefits for peripheral metabolism 1 . The intestinal production of SCFA has been assessed in vitro 5 , in in vivo animal models (pigs, dogs, rats) 1 and also in human subjects 6 . Most studies have been limited to the determination of SCFA concentrations in biological fluids in animals and human subjects and only a few have investigated the peripheral turnover rate of acetate or of propionate 3,7 -9 . To our knowledge no studies have investigated the peripheral turnover rates of propionate and butyrate after dietary fibre ingestion in either animals or human subjects.The production of SCFA in the intestine occurs at a rate that depends upon the rate of entry of unabsorbed nutrients into the intestine and bacterial activity within the gut. It varies from a minimum during fasting, to a maximum ...