# Effects of Japan tallow on gut microbiota in type 2 diabetic mice

## TL;DR

This study shows that Japan tallow improves diabetes symptoms in mice by balancing gut bacteria and improving metabolism.

## Contribution

The study experimentally demonstrates that Japan tallow improves T2DM in mice via gut microbiota modulation.

## Key findings

- Japan tallow improved glycemic control and insulin sensitivity in T2DM mice.
- Japan tallow restored gut microbiota balance toward a healthier composition.
- Tissue damage in the liver, pancreas, and colorectum was reduced with Japan tallow.

## Abstract

Black Japan tallow (BJT) and white Japan tallow (WJT), collectively referred to as Japan tallow (JT), are traditional edible oils widely consumed in the Nujiang region of Yunnan, China. JT has been traditionally used for its potential health benefits, including anti-diabetic effects. However, scientific evidence supporting these claims is limited, and the underlying mechanisms remain unclear. This study aimed to evaluate the anti-diabetic effects of JT and to explore whether its action involves modulation of the gut microbiota.

The lipidomic profile of JT was first characterized. Thirty C57BL/6J mice were randomly divided into five groups (n = 6): control group (ND), T2DM group (T2DM), dietary intervention group (CTRL), metformin treatment group (MET), and JT intervention group (JT). T2DM was induced by a high-fat diet (HFD) combined with low-dose streptozotocin (STZ) injections in all groups except ND. Body weight, food intake and fasting blood glucose (FBG) were monitored weekly. Metabolic responses were assessed using oral glucose tolerance test (OGTT) and insulin tolerance test (ITT). After four weeks, fecal samples were collected for 16 S rDNA sequencing, and tissue samples from the colorectum, liver, and pancreas were harvested for histological analysis.

Lipidomic analysis identified 230 distinct lipid molecules in JT. BJT showed higher abundances of unsaturated ceramide (Cer t18:1_22:1) and OAHFA (42:7). JT intervention significantly improved glycemic control, enhanced insulin sensitivity, and ameliorated tissue damage in the colorectum, liver, and pancreas of T2DM mice. Furthermore, 16 S rDNA sequencing indicated that JT intervention restored gut microbiota balance, shifting its composition toward a healthy state.

JT exhibits significant anti-diabetic effects in a mouse model of T2DM, likely mediated through the restoration of gut microbiota homeostasis and improvement of metabolic parameters. These findings provide experimental support for the traditional use of JT and form a basis for future studies on its translational potential.

The online version contains supplementary material available at 10.1186/s12986-026-01079-3.