Dietary fructans, but not cellulose, decrease triglyceride accumulation in the liver of obese Zucker fa/fa rats

Area of Science:

• Metabolic research
• Nutritional science
• Gastroenterology

Background:

• Obesity is associated with hepatic steatosis (fatty liver disease).
• Dietary nondigestible carbohydrates can modulate gut microbiota and host metabolism.
• The fermentability of carbohydrates influences their metabolic effects.

Purpose of the Study:

• To investigate the impact of dietary fructans (highly fermentable) versus cellulose (poorly fermentable) on hepatic steatosis in obese Zucker rats.
• To explore the underlying mechanisms, including energy intake, body weight, and liver lipid accumulation.

Main Methods:

• Obese Zucker rats were fed diets supplemented with fructans, cellulose, or a control diet.
• Liver fat accumulation was assessed using in vivo nuclear magnetic resonance (NMR) spectroscopy and ex vivo biochemical/histochemical analyses.
• Cecal contents, portal vein propionate concentration, and hepatocyte lipid synthesis were measured.

Main Results:

• Fructan-fed rats exhibited lower energy intake, body weight, and liver triacylglycerol accumulation compared to control and cellulose groups.
• Fructans led to greater cecal contents and significantly higher portal vein propionate levels.
• Propionate selectively reduced acetate incorporation into lipids in isolated hepatocytes.

Conclusions:

• Highly fermentable dietary fructans ameliorate hepatic steatosis in obese rats.
• Increased propionate production from fructan fermentation may contribute to reduced liver triglyceride accumulation.
• These findings highlight the role of carbohydrate fermentability in managing metabolic dysfunction.