This week on BBS: Diet changes microflora in the obese, Lactobacilli thrive on artificial sweeteners, and L. reuteri probiotics fight cancer.
Dieting Changes Gut Bacteria
Gut microbiota changes may impact weight loss in obese individuals. To determine if dietary changes could change intestinal microbiota in obese individuals, scientists from Finland placed 12 obese people on a very low energy diet and evaluated changes in their intestinal microflora. They found that patients had lowered Bifidobacteria and that changes in the microflora were correlated with dietary intake and not weight loss. This would suggest that diet has a larger impact on the intestinal microbiota than the current weight of the individual.
Artificial Sweetener Stimulates Lactobacilli
Lactic acid bacteria, like Lactobacilli, use sugars as food for growth. To determine the effect of artificial sweeteners on these bacteria in vivo, scientists from the United Kingdom and Switzerland fed pigs different types of sweeteners and examined their intestinal bacteria. Surprisingly, artificial sweeteners (saccharin and NHDC) also encouraged growth of Lactobacilli just like their preferred sugar, lactose. This is the first time that artificial sweeteners have been shown to have prebiotic properties.
Lactobacillus reuteri May Help Cancer
Cancer susceptibility is increased by both genetic predisposition and the typical Western diet. However, modulating the immune system can often reduce cancer, and probiotics are known to influence immunity. With this idea in mind, scientists from MIT experimented in mouse models of breast cancer, attempting to prevent cancer with the probiotic species Lactobacillus reuteri. They found that probiotic supplementation caused increases in regulatory T cells, cells designed to counter-act inflammation. The scientists speculated that L. reuteri supplementation could be a feasible way to counteract some cancer susceptibility in Western populations.
- Simoes CD, Maukonen J, Scott KP, Virtanen KA, Pietilainen KH, Saarela M. Impact of a very low-energy diet on the fecal microbiota of obese individuals. Eur J Nutr 2013. [Epub ahead of print]
- Daly K, Darby AC, Hall N, Nau A, Bravo D, Shirazi-Beechey SP. Dietary supplementation with lactose or artificial sweetener enhances swine gut Lactobacillus population abundance. Br J Nutr 2014: 1-6. [Epub ahead of print]
- Lakritz JR, Poutahidis T, Levkovich T, Varian BJ, Ibrahim YM, Chatzigiagkos A et al. Beneficial bacteria stimulate host immune cells to counteract dietary and genetic predisposition to mammary cancer in mice. Int J Cancer 2013. [Epub ahead of print]