This week on BBS: Northern latitudes influence intestinal microbiota, and the prebiotic xylooligosaccharides encourages the growth of Bifidobactera.
Northern and Southern Microbiota
Humans that have adapted to colder climates generally have an increased body mass. Because it’s now clear that obesity is associated with changes in the intestinal microbiota, Dr. Taichi A. Suzuki of the University of California at Berkeley considered that microbiota might also change in populations located at different latitudes. They looked at data collected for 23 populations from previously published studies. Changes in the microbiota found in obese individuals were also mirrored in populations located at high latitudes. Specifically, relative amounts of phyla Firmicutes increased while the amounts of Bacteroidetes decreased.
More Prebiotics for Bifidobacteria
Xylooligosaccharides (XOS) are polymers of the simple sugar xylose, and they have prebiotic potential. To determine more about their function in the human gastrointestinal tract, Dr. Sydney M. Finegold of the VA Medical Center in Los Angeles provided 32 healthy adults with XOS for four weeks. Fecal culture samples revealed that XOS increased the Bifidobacteria counts. Those with the highest doses also had increased anaerobic bacteria counts and the species Bacteroides fragilis. Other types of bacteria remained unchanged along with the fecal pH, SCFA and lactic acid.
- Suzuki TA, Worobey M. Geographical variation of human gut microbial composition. Biol Lett 2014; 10(2): 20131037.
- Finegold SM, Li Z, Summanen PH, Downes J, Thames G, Corbett K et al. Xylooligosaccharide increases bifidobacteria but not lactobacilli in human gut microbiota. Food Funct 2014. [Epub ahead of print]