Skip to main content
ARS Home » Southeast Area » Little Rock, Arkansas » Microbiome and Metabolism Research Unit » Research » Publications at this Location » Publication #341879

Title: Soy compared with milk protein in a western diet changes fecal microbiota and decreases hepatic steatosis in obese OLETF rats

item PANASEVICH, MATTHEW - University Of Missouri
item SCHUSTER, COLIN - University Of Missouri
item PHILLIPS, K - University Of Missouri
item MEERS, GRACE - University Of Missouri
item CHINTAPALLI, SREE - University Arkansas For Medical Sciences (UAMS)
item WANKHADE, UMESH - University Arkansas For Medical Sciences (UAMS)
item SHANKAR, KARTIK - Arkansas Children'S Nutrition Research Center (ACNC)
item BUTTEIGER, DUSTINE - Dupont Nutrition & Health
item KRUL, ELAINE - Dupont Nutrition & Health
item THYFAULT, JOHN - University Of Kansas
item RECTOR, R - University Of Missouri

Submitted to: Journal of Nutritional Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/17/2017
Publication Date: 5/31/2017
Citation: Panasevich, M.R., Schuster, C.M., Phillips, K.E., Meers, G., Chintapalli, S.V., Wankhade, U.D., Shankar, K., Butteiger, D.N., Krul, E., Thyfault, J.P., Rector, R.S. 2017. Soy compared with milk protein in a western diet changes fecal microbiota and decreases hepatic steatosis in obese OLETF rats. Journal of Nutritional Biochemistry. 46:125-136. doi:10.1016/j.jnutbio.2017.05.004.

Interpretive Summary: Consuming soy-rich diets may impact health of a variety of the body's systems including bone, body fat, and metabolism. However, how consumption of soy diets may mitigate accumulation of fat in the liver is less well appreciated. In this study, a strain of rats prone to develop obesity and fatty liver were provided high-fat, high-sugar diets containing either milk or soy protein. The latter was to test if inclusion of soy protein can ameliorate negative effects of an obesigenic diet. Animals fed soy protein showed significant reduction in fatty liver severity and accumulation of specific lipids (fats) in the liver. These changes were associated with significant shifts in the natural gut bacteria (microbiota) of the rats, with soy diets increasing the abundance of Lactobacillus bacteria and decreasing bacteria involved in bile acid metabolism. Soy diets also modulated other components of hepatic lipid biosynthesis and bile acid/cholesterol metabolism. Overall, these studies highlight novel mechanisms suggesting contributions of microbe populations and bile acid metabolism in beneficial effects associated with soy consumption on liver health.

Technical Abstract: Soy protein is effective at preventing hepatic steatosis; however, the mechanisms are poorly understood. We tested the hypothesis that soy versus dairy protein-based diet would alter microbiota and attenuate hepatic steatosis in hyperphagic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Male OLETF rats were randomized to "Western" diets containing milk protein isolate (MPI), soy protein isolate (SPI), or 50:50 MPI/SPI (MS) (n=9-10/group; 21% kcal protein) for 16 weeks. SPI attenuated (P<0.05) fat mass and percent fat by ~10% compared with MS, but not compared with MPI. Serum TBAR and total and LDL-cholesterol concentrations were lower (P<0.05) with dietary SPI versus MPI and MS. Histological hepatic steatosis was lower (P<0.05) in SPI compared with MPI or MS. Lipidomic analyses revealed reductions (P<0.05) in hepatic diacylglycerols but not triacylglycerols in SPI compared with MPI, which was associated with lower hepatic de novo lipogenesis (ACC, FAS, and SCD-1 protein content, and hepatic 16:1 n-7 and 18:1 n-7 PUFA concentrations) (P<0.05) compared with MPI and MS; however, MPI displayed elevated hepatic mitochondrial function compared with SPI and MS. Fecal bacterial 16S rRNA analysis revealed SPI-intake elicited increases (P<0.05) in Lactobacillus and decreases (P<0.05) in Blautia and Lachnospiraceae suggesting decreases in fecal secondary bile acids in SPI rats. SPI and MS exhibited greater (P<0.05) hepatic Fxr, Fgfr4, Hnf4a, HmgCoA reductase and synthase mRNA expression compared with MPI. Overall, dietary SPI compared with MPI decreased hepatic steatosis and diacylglycerols, changed microbiota populations, and altered bile acid signaling and cholesterol homeostasis in a rodent model of obesity.