The rate of overweight and obese adults continues to rise in the US and world. Obese women have higher risk and mortality rates from all types of cancers including breast cancer. The intestinal microbiota is composed of a diverse population of obligate and facultative anaerobic microorganisms, and these organisms carry out a broad range of metabolic activities. Previously, we reported that a soy protein diet containing high isoflavone levels promoted 7, 12 dimethylbenz [a]anthracene (DMBA) induced mammary tumor development compared to a casein-based diet and the plasma equol was significantly lower in obese soy-fed rats compared to lean soy-fed rats. Obesity has been linked to changes in the intestinal microbiota, but the effects of obesity and soy protein diet on the composition of the intestinal microbiota have not been studied. The objective of study was to determine the effects of obesity and diet containing soy protein isolate on gut microbiota. Lean and obese female Zucker rats (n = 34) were randomly assigned to 1) casein, or 2) soy protein diets for 8 weeks. Fecal samples, collected at the end of the experiment, were analyzed using 16S rRNA gene sequencing to determine the bacterial populations present. Bacterial DNA was isolated from the fecal samples using a commercial kit and the DNA prepared for sequencing using barcoded primers specific for the Illumina MiSeq platform. Following sequencing, the readings were de-multiplexed and the different taxa identified to characterize the total bacterial populations. Our results suggest that there are differences in gut microbiota associated with diet and the lean/ obese state. Further investigation will be needed to determine the effects of obesity and soy protein diet on gut microbiota in relation to DMBA-induced mammary tumor formation.
Citation: Proceedings of the Inaugural International Conference on Obesity and Chronic Diseases (ICOCD-2016). J Obes Chronic Dis 1(Suppl 1): S1-S49.