Calorie Restriction Prevents Age-Related Changes in the Intestinal Microbiota

The effect of calorie restriction (CR) on the microbiome from the cecum and colon of adult and old male mice was compared. Life-long CR increased microbial diversity and the Bacteriodetes/Fermicutes ratio and prevented the age-related changes in the microbiota, shifting it to a younger microbial profile in both C57BL/6JN and B6D2F1 mice. Old mice fed CR were enriched in the Rikenellaceae, S24-7 and Bacteroides families. The changes in the microbiome that occur with age and CR were initiated in the cecum and modified as the fecal material progresses to the colon. Short-term CR in adult mice had a minor effect on the microbiome but a major effect on the transcriptome of the colon mucosa. These data suggest that the primary impact of CR is on the physiological status of the gastrointestinal system, maintaining it in a more youthful state, which in turn results in a more diverse and youthful microbiome.