Interaction between methane-producing status and diet on serum acetate concentration in humans

About half the population excretes methane in the breath. To see if methane producing status influenced serum acetate, we studied six methane producers and six nonproducers on three separate days. For 36 h they ate a polysaccharide-free diet alone, or with 20 g of unabsorbed sugar lactulose, or 20 g of fermentable fiber, guar, in random order. The mean fasting serum acetate concentration on the three test days in producers was higher than in nonproducers, 84 +/- 5 vs. 69 +/- 5 mumol/L (P < 0.05). Compared to the control diet, both lactulose and guar raised serum acetate concentration significantly in both groups of subjects. However, there was a significant interaction between methane producing status and diet. After lactulose consumption, postprandial serum acetate was similar in both groups of subjects, but guar consumption had a significantly greater effect in producers than nonproducers (98 +/- 8 vs. 73 +/- 5 mumol/L; P < 0.05). We conclude that methane producing status may influence serum acetate concentrations in humans, depending upon the type of fermentable carbohydrate in the diet.