Sodium propionate

Abstract: Propionate produced in the colon from the fermentation of alpha-amylase-resistant starch and non-starch polysaccharides, is cholesterol lowering and gluconeogenic in animal models. In humans, little is known about the effect of propionate on metabolism. In a double-blind, paired-comparison, placebo-controlled study, the diet of 10 healthy female volunteers, aged 20-22 yr, was supplemented for a period of 7 wk with 7.5 g sodium propionate daily in capsule form, while the diet of the 10 control group members was supplemented with dibasic calcium phosphate in identical capsules as placebo. Propionate supplementation did not lower total serum cholesterol (TC), but increased HDLC (9.5%) (p less than 0.05) and triglyceride levels (16.7%, p less than 0.02) and decreased fasting serum glucose and maximum insulin increments during glucose tolerance tests (p less than 0.05). The results suggest that the improvement in glucose tolerance and insulin sensitivity and the known beneficial effect of dietary fiber on HDL metabolism may in part be mediated through effects of propionate on hepatic carbohydrate metabolism.

Abstract: Summary Twelve young dairy calves equipped with rumen cannulae were fed milk and housed in tie stalls with elevated floors to prevent bedding consumption. Sodium acetate, sodium propionate, sodium butyrate, sodium chloride, and glucose were administered over an 11-wk. period, to study their effect on rumen mucosal development. Two calves served as controls. Administration of solutions of sodium butyrate or sodium propionate caused marked development of the rumen mucosa, whereas the other materials caused relatively little growth. It is hypothesized that the growth of rumen papillae is probably a result of the metabolism of certain compounds by the rumen wall and/or their effect on blood flow in the rumen.

Abstract: Solutions containing 90 mmol sodium acetate plus 30 mmol sodium propionate (90 mM; isotonic), 180 mmol acetate plus 60 mmol propionate (180 mM; hypertonic) or an equivalent volume of isotonic saline were given over a 30-min period in random order by rectal infusion to six healthy subjects. Peripheral venous blood samples were obtained at 30-min intervals over the next 2 h. After the 90 mM infusion, the serum acetate response reached a peak at 60 min and had fallen to baseline by 120 min. The incremental area under the serum acetate response curve after 180 mM was twice that after 90 mM. Propionate was undetectable in serum at any time. Blood glucose fell after all of the infusions, but there was no significant difference between the saline- and short chain fatty acid (SCFA)-containing infusions. SCFA had no significant effect on serum insulin or c-peptide concentrations. However, compared with the saline control, the 180 mM solution resulted in a significant fall in serum free-fatty acids (FFA) and a significant rise in serum total cholesterol and triglyceride, with no change in beta-hydroxybutyrate levels. The data provide strong evidence that colonic SCFA are absorbed and metabolized in the human subject. The fall in FFA suggests that colonic SCFA have an effect on carbohydrate metabolism. In addition, the data provide indirect evidence for utilization of SCFA for lipid synthesis.

Abstract: Incorporation of 3.3 g sodium propionate per 50 g available carbohydrate portion of bread reduced acutely the blood glucose response area in six healthy volunteers by 47.6 +/- 12.1% Similarly, in vitro digestibility was reduced by 47.4 +/- 1.1% (P less than 0.01). One week of dietary supplementation with 9.9 g sodium propionate in bread/d reduced the blood glucose area in comparison with standard propionate-free bread by 38.0 +/- 8.7% (P less than 0.05), but increased fecal bulk by 28.3 +/- 8.7% (P less than 0.05) and anaerobic microflora by 0.564 +/- 0.165 X 10(6)/g feces (P less than 0.05), specifically as bifidobacteria. Day-long breath hydrogen concentrations did not increase after 1 wk on propionate bread but methane production increased in the three methane producers. Although lipid changes were not significant, five subjects showed reduced high-density-lipoprotein and increased triglyceride concentrations, both of which correlated with increased fecal weight (P less than 0.05). Because propionate reduces the rate of starch digestion, studies using oral propionate must take into account its action as an enzyme inhibitor.

Abstract: The combination of plant oils and 3-hydroxyvalerate (3HV) precursors were evaluated for the biosynthesis of polyhydroxyalkanoate (PHA) copolymers containing 3HV monomers by Cupriavidus necator H16. Among various mixtures of plant oils and 3HV-precursors, the mixture of palm kernel oil and sodium propionate was suitable for the biosynthesis of high concentration of PHA (6.8 g L −1 ) containing 7 mol% of 3HV. The 3HV monomer composition can be regulated in the range of 0–23 mol% by changing culture parameters such as the initial pH, and the nitrogen source and its concentration. PHA copolymers with high weight-average molecular weights ( M w ) ranging from 1,400,000 to 3,100,000 Da were successfully produced from mixtures of plant oils and 3HV-precursors. The mixture of plant oils and sodium propionate resulted in PHA copolymers with higher M w compared to the mixture of plant oils and sodium valerate. DSC analysis on the PHA containing 3HV monomers showed the presence of two distinct melting temperature ( T m ), which indicated that the PHA synthesized might be a blend of P(3HB) and P(3HB- co -3HV). Sodium propionate appears to be the better precursor of 3HV than sodium valerate.