Researchers investigated the relationship between lactose digestion, gastrointestinal transit time, and symptoms in lactose malabsorbers.
They reported their findings in April's Alimentary Pharmacology and Therapeutics.
22 lactose malabsorbers were enrolled in the double-blind trial.
Each received 25 g daily lactose in fresh (living bacteria >108 cfu/g) yogurt, or heated (<102 cfu/g) yogurt for 15 days, followed by a cross-over (15 days) after a wash-out period (14 days).
The H2-breath test, the gastric emptying with a 13C-acetate breath test, and the revealed oro-cecal transit time (OCTT) by 15N-lactose-ureide test were all used to determine lactose digestion.
The H2-breath test indicated more effective lactose digestion after fresh yogurt intake.
The OCTT was found to be shorter after heated yogurt ingestion as compared with the fresh.
In addition, there was lower severity of gastrointestinal symptoms after fresh yogurt intake, and this showed an inverse correlation with OCTT.
Researcher I. Labayen, of the University of Navarra, Pamplona, Spain, concluded on behalf of the group, "Delayed oro-cecal transit time was associated with fewer gastrointestinal symptoms.
"The improved lactose digestion and tolerance of fresh yogurt should be mainly attributed to the presence of living bacteria."