Anti-obesity and other health benefits of bioprocessed black rice bran in combination with green tea extract in 3T3-L1 preadipocyte cells and in mice on a high-fat diet

Black rice bran, a waste product from the commercial milling of black rice that removes the bran and germ leaving the starchy endosperm, contains bioactive anthocyanin, phenolic, and phytosteroid compounds that may have health benefits. This study determined the effect of a polysaccharide-rich bioprocessed (fermented) black rice bran and a green tea extract individually and in combination on weight loss in orally fed mice on a high-fat diet and on concurrent changes in blood glucose and insulin as well as in cholesterol, triglyceride, and high-density and low-density lipoproteins (HDL and LDL). At the end of the eight-week feeding study, the combination diet resulted in a 67% lower weight gain than mice on a high-fat diet alone, a greater effect than that of bioprocessed black rice bran or green tea extract individually. The weight loss caused by the combination diet seems to be the result of decreased dietary efficiency. The observed trends in the glucose and insulin data suggest that the combined diet also has anti-diabetic properties, and the corresponding trends in the levels of the serum lipoproteins suggest that the combined diet might also protect against heart disease. Effects on the content, structure, and function of white adipose and liver tissues and on obesity-related biomarkers support the trends in the weight loss data. Based on the observed beneficial effects in 3T3-L1 pre-adipocyte cells and mice, we suggest the need to investigate if the new multifunctional combination food product can also protect against obesity and chronic diseases in humans. Mechanistic aspects that govern the anti-obesity effects and suggestions for future research are discussed.