American Journal of Clinical Nutrition, Vol 25, 763-765, Copyright © 1972 by The American Society for Clinical Nutrition, Inc.

Effect of oral lactobacillus feedings on fecal lacto bacillus counts

¹ From the Gastroenterology Unit, Veterans Administration Hospital and the Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106

Reports suggesting that oral feedings of L. acidophilus with lactose benefited patients with hepatic encephalopathy prompted us to determine if oral feedings of these lactobacilli altered the fecal aerobic (microaerophilic) lactobacillus count. The fecal aerobic lactobacillus counts per gram wet weight of stool were determined in multiple stool specimens from 10 subjects before, during, and following oral administration of a commercial preparation of lyophilized lactobacilli, predominantly L. acidophilus. Prior to administration of oral lactobacilli, the mean FALC differed by as much as a millionfold among the subjects, but the FALC from day to day for each subject showed smaller variations that were one hundredfold or less in nine subjects. During administration of 10⁸ to 10⁹ viable lactobacilli per day, the FALC increased initially in five subjects but returned to pretreatment levels within 10 days despite continued administration of the organisms and in five subjects the FALC did not change. One subject showed an increase in FALC during treatment that persisted at high levels for 3 weeks after lactobacillus feedings were stopped before returning to pretreatment levels. No increase in FALC occurred when this subject was given a second course of oral lactobacilli. In all others, the posttreatment counts were similar to their pretreatment counts. We conclude that oral lactobacillus feedings have no appreciable or sustained effect on the size of the colonic aerobic lactobacillus population as measured by fecal counts.