Recently, Korean traditional fermented soybean paste, called Doenjang, has attracted attention for its
protective effect against diet-related chronic diseases such as obesity and type 2 diabetes. Long-term
fermented soybean pastes (LFSPs) are made by fermentation with naturally-occurring microorganisms
for several months, whereas short-term fermented soybean pastes (SFSPs) are produced by shorter-time
fermentation inoculated with a starter culture. Here, we demonstrate that administration of LFSP, but not
SFSP, protects high-fat diet (HFD)-fed obese mice against non-alcohol fatty liver disease (NAFLD) and
insulin resistance. LFSP suppressed body weight gain in parallel with reduction in fat accumulation i... More
Recently, Korean traditional fermented soybean paste, called Doenjang, has attracted attention for its
protective effect against diet-related chronic diseases such as obesity and type 2 diabetes. Long-term
fermented soybean pastes (LFSPs) are made by fermentation with naturally-occurring microorganisms
for several months, whereas short-term fermented soybean pastes (SFSPs) are produced by shorter-time
fermentation inoculated with a starter culture. Here, we demonstrate that administration of LFSP, but not
SFSP, protects high-fat diet (HFD)-fed obese mice against non-alcohol fatty liver disease (NAFLD) and
insulin resistance. LFSP suppressed body weight gain in parallel with reduction in fat accumulation in
mesenteric adipose tissue (MAT) and the liver via modulation of MAT lipolysis and hepatic lipid uptake.
LFSP-treated mice also had improved glucose tolerance and increased adiponectin levels concomitantly
with enhanced AMPK activation in skeletal muscle and suppressed expression of pro-inflammatory
cytokines in skeletal muscle and the liver. LFSP also attenuated HFD-induced gut permeability and
lowered serum lipopolysaccharide level, providing an evidence for its probiotic effects, which was
supported by the observation that treatment of a probiotic mixture of LFSP-originated Bacillus strains
protected mice against HFD-induced adiposity and glucose intolerance. Our findings suggest that the
intake of LFSP, but not SFSP, offers protection against NAFLD and insulin resistance, which is an effect of
long-term fermentation resulting in elevated contents of active ingredients (especially flavonoids) and
higher diversity and richness of Bacillus probiotic strains compared to SFSP.