Chronic consumption of fresh but not heated yogurt improves breath-hydrogen status and short-chain fatty acid profiles: a controlled study in healthymen with or without lactose maldigestion

Background: Ingestion of fermented dairy products induces changes in the eq uilibrium and metabolism of the intestinal microflora and may thus have ben eficial effects on the host. Objective: We compared the effects of chronic consumption of yogurt with (f resh) or without (heated) live bacterial cultures (Lactobacillus bulgaricus and Streptococcus thermophilus) on plasma glucose, insulin, triacylglycero ls, cholesterol, fatty acids, and short-chain fatty acids. Design: Two groups of 12 healthy men with or without lactose malabsorption were selected with use of a breath-hydrogen test after a 30-g lactose load. Subjects were randomly assigned in a crossover design to 500 g/d of either fresh or heated yogurt for 2 periods of 15 d each, separated by a 15-d was hout interval. Results: Chronic consumption of fresh or heated yogurt had no detrimental e ffects on plasma glucose, insulin, or fatty acid areas under the curve in r esponse to acute ingestion of 500 g yogurt in healthy men with or without l actose malabsorption. There were also no detectable changes in fasting plas ma glucose, insulin, fatty acid, triacylglycerol, or cholesterol concentrat ions. In contrast, plasma butyrate was higher (P < 0.03) and plasma propion ate tended to be higher (P = 0.059) in subjects without lactose malabsorpti on after fresh yogurt consumption than after heated yogurt consumption. The re were no significant changes in plasma acetate. In subjects with lactose malabsorption, 15 d of fresh yogurt consumption also increased propionate p roduction compared with values at baseline (P < 0.04). In the same group, t he production of breath hydrogen was lower after fresh yogurt consumption t han after heated yogurt consumption (P < 0.01). Conclusions: In men with lactose malabsorption, chronic consumption of yogu rt containing live bacterial cultures ameliorated the malabsorption, as evi denced by lower breath-hydrogen excretion, but increased propionate concent rations. In subjects without lactose malabsorption, such yogurt tended to i ncrease propionate and increased butyrate.