EFFECT OF LACTIC-ACID BACTERIA ON THE INTESTINAL PRODUCTION OF LACTATE AND SHORT-CHAIN FATTY-ACIDS, AND THE ABSORPTION OF LACTOSE

The characteristic fermentation pattern seen with specific saccharides in incubations with pure cultures of Lactobacillus acidophilus and Bi fidobacterium bifidum disappeared when incubated in 16.7% fecal homoge nate. The productions of lactate and short-chain fatty acids in mixed bacterial-fecal incubations were similar to productions in fecal homog enates without L acidophilus and B bifidum and were mainly associated with the specific mono-, di-, and polysaccharides added to the incubat e. B bifidum was cultured from ileostomic contents in eight of nine il eostomists after oral administration (2.4X10(10) cells), but did not i nfluence the concentrations and productions of DL-lactate and short-ch ain fatty acids in the ileostomic outputs and incubates. Large amounts of ingested lactic acid bacteria (4.2x10(10) cells) did not ameliorat e lactose malabsorption measured by the breath-hydrogen test in 12 lac tose malabsorbers. This study shows that ingested lactic acid bacteria are indeed present in the colon, but it does not support the theory t hat they change the pattern of colonic fermentation or the degree of i ntestinal lactose malabsorption.