Fermented foods improve symptoms associated with a high-fat diet

During the fermentation process, these microorganisms synthesize vitamins and minerals, produce bioactive peptides with enzymes such as proteases and peptidases, and remove some non-nutritional substances. Bioactive peptides are widely known to be produced by the microorganisms responsible for fermentation. Fermented foods have many health benefits, such as antioxidant, antimicrobial, antifungal, anti-inflammatory, antidiabetic and antiatherosclerotic activities.

Recent Research Results

01 Natto alleviates hyperlipidemia in mice fed a high-fat diet by regulating the composition and metabolic function of the intestinal microbiota

Abstract:

Natto has long been considered a medical and edible product with lipid-lowering effects. This study showed that natto can effectively reduce the levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), fasting blood glucose (FBG) in the serum of hyperlipidemic mice, and increase the level of high-density lipoprotein cholesterol (HDL-C). Metabolic analysis showed that natto can increase the level of amino acid metabolites, reduce the content of acylcarnitines, and reverse the level of purine alkaloids, mainly involving the tricarboxylic acid cycle and amino acid metabolism. In addition, natto increased beneficial intestinal microbiota (such as Lactobacillus, Faecalibacterium, and Oscillospira) and reduced pathogenic intestinal microbiota (such as Alternaria and Prevotella-UCG-003). In summary, natto-mediated changes in intestinal microbiota and its related metabolites can support the prevention of high-fat diet (HFD)-induced hyperlipidemia, laying a theoretical foundation for the continued development of natto as a functional food.

Conclusion:

In this study, 8 weeks of natto treatment significantly improved the glucose and lipid metabolism disorders in hyperlipidemic mice. Natto's regulation of dyslipidemia was mainly through inhibiting pathogenic bacteria and stimulating beneficial bacteria to improve the composition and abundance of intestinal flora, as well as the TCA cycle, amino acid metabolism, and purine metabolism of related metabolites. The results suggest that natto has potential application in the prevention of hyperlipidemia. However, the relationship between natto's lipid-lowering properties and its ability to regulate intestinal microbiota, as well as the connection between intestinal microbiota and its metabolites, requires further studies to confirm.

02 Preventive effects of fermented and unfermented millet bran soluble dietary fiber on high-fat diet-induced obesity in mice

Abstract:

Obesity-related diabetes, cardiovascular disease, and hypertension pose many risks to human health. Therefore, in this study, mice fed a high-fat diet were gavaged with rice bran (unfermented/fermented) soluble dietary fiber (RSDF/FSDF, 500 mg/kg) for 10 weeks and various biological indices were evaluated. The results showed that RSDF and FSDF supplementation could prevent fat synthesis by inhibiting sterol regulatory element binding protein 1c gene expression. RSDF could also accelerate fat catabolism by increasing the mRNA expression levels of adipose triglyceride lipase and peroxisome proliferator-activated receptor α. FSDF supplementation could prevent obesity by reducing 3-hydroxy-3-methylglutaryl-CoA reductase expression and increasing cholesterol 7α-hydroxylase expression. In addition, FSDF also controlled the development of obesity by reducing total cholesterol and low-density lipoprotein cholesterol levels in the blood, triglycerides, total cholesterol, and bile acid levels in the liver. It is noteworthy that FSDF supplementation can promote the reproduction of Bacteroides and Prevotella; the excreted propionic acid binds to free fatty acid receptor 2/3, stimulates intestinal epithelial cells to produce glucagon-like peptide-1 and peptide YY, reduces food and energy intake, and ultimately prevents obesity.

Conclusion:

Millet bran RSDF and FSDF can effectively prevent obesity and relieve hyperlipidemia and non-alcoholic hepatic steatosis. The preventive effect of FSDF is better than that of RSDF. Both grain bran SDFs achieve the purpose of preventing HFD-induced obesity through different mechanisms. The mechanisms may include changing the metabolism, digestion and absorption of BA, TG and cholesterol, regulating the expression of TG and cholesterol metabolism-related genes, stimulating the secretion of intestinal anorexigenic hormones including GLP-1 and PYY, reducing appetite and energy intake. Regulating SCFA levels and intestinal flora composition. Therefore, millet bran SDF, especially FSDF, has great potential in preventing obesity and related chronic diseases.

03 Fermented fruits improve obesity by controlling food intake and regulating lipid metabolism in mice fed a high-fat diet

Abstract:

Some fruits have anti-obesity effects after long-term fermentation, but their mechanisms have not been systematically determined. This study aims to screen effective fermented fruits and explore their mechanisms of action. C57BL/6J male mice were fed a high-fat diet (HFD) to establish an obesity model, and 9 fermented fruits were given for intervention. Fermented fruits can significantly reduce body weight gain (BWG), average daily feed intake (ADFI) and adipose tissue index, and alleviate liver steatosis. Serum triglycerides (TG) and total cholesterol (T-CHO) were significantly reduced, and leptin was significantly increased. PPARα and CPT1 were upregulated, while PPARγ and aP2 were downregulated. In addition, fermented fruits improved the intestinal flora structure of mice fed a HFD. Studies have shown that fermented fruits, especially fermented blueberries and fermented apples, can improve obesity by controlling food intake, regulating lipid metabolism and intestinal microbiota dysbiosis, and may replace anti-obesity drugs.

Conclusion:

This study confirmed that fermented fruits, especially fermented blueberries and fermented apples, have highly effective anti-obesity functions, and their mechanisms of action may include controlling food intake through the leptin pathway. Regulating fatty acid lipid synthesis and β-oxidation gene and protein expression, and improving intestinal flora ecology. These properties suggest that fermented fruits have the potential to replace drugs in the treatment of obesity and obesity-related metabolic disorders.

04 Lactobacillus casei fermented radix aconitifolii alleviates non-alcoholic fatty liver disease in a high-fat diet mouse model

Abstract:

Non-alcoholic fatty liver disease (NAFLD) has become a major global health problem due to its high prevalence and lack of effective treatment. Traditional Chinese medicine fermentation has been considered a feasible approach to improve the efficacy of various diseases. This study investigated the potential benefits of Lactobacillus casei fermented radix aconitifolii (LAX) on a high-fat diet model of NAFLD. C57BL6/j mice fed a HFD were given LAX or unfermented radix aconitifolii (AX) with 200 or 100 mg/kg metformin for 6 weeks starting from week 4. LAX significantly attenuated the changes in hepatic lipid accumulation and liver inflammation induced by 10 weeks of HFD (more than AX or metformin) in terms of pathological histology, lipid content, and the contents of inflammatory factors such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β. Oxidative parameters such as reactive oxygen species (ROS) and malondialdehyde (MDA), as well as molecular reverse changes between lipogenic proteins such as glycerol-3 phosphate acyltransferase (GPAM) and sterol regulatory element binding protein (SREBP), and liposoluble proteins in liver tissue, including peroxisome proliferator-activated receptor (PPAR-α) and AMP-activated kinase (AMPK)-α. In addition, abnormal blood lipid parameters (triglycerides, total cholesterol, and low-density lipoprotein cholesterol) were significantly improved. In conclusion, these findings support the potential of LAX as a promising plant-derived drug for NAFLD.

Conclusion:

The results showed that the fermentation process of Lactobacillus casei enhanced the effects of LAX, and LAX may be a promising candidate plant for alleviating NAFLD including metabolic disorders. The potential mechanisms include the balance between lipogenic and lipolytic activities in liver tissue as well as antioxidative and inflammatory effects. Nevertheless, the components of Lactobacillus casei fermented radish remain unclear. Therefore, further studies will include the use of mass spectrometry and network pharmacology approaches to identify the active components in Lactobacillus casei fermented radish.