Fermented Foods and Health

Kathryn Adel December 4, 2025 Diabetes, FODMAP, gastrointestinal health, Health, Heart Health, Weight Loss

Fermented Foods, Gut Microbiome, and Inflammation

A clinical study conducted at Stanford University in California evaluated the effects of a high-fiber diet versus a diet high in fermented foods on the gut microbiota and inflammation. 39 participants were randomized into two groups and followed a diet for ten weeks. Subjects following the high-fiber diet increased their fiber intake to an average of 45g per day, while subjects following the diet rich in fermented foods increased their consumption of fermented foods to an average of six servings per day. Both diets were associated with greater microbiota diversity (i.e., a greater number of different beneficial bacteria in the gut) and a decrease in various inflammatory markers, but the effects were even greater with the diet rich in fermented foods.

Fermented Foods and Cardiometabolic Disease

According to a meta-analysis including ten cohort studies (total of 385,122 participants), the consumption of fermented dairy products is associated with a reduced risk of cardiovascular disease. Another systematic review and meta-analysis including 18 randomized controlled trials (total of 843 participants) evaluated the effects of fermented foods in patients with diabetes and prediabetes. The combined results showed a significant reduction in fasting blood glucose, HOMA-IR index (homeostatic model assessment of insulin resistance), total cholesterol, LDL cholesterol, and diastolic blood pressure in the intervention group compared to the control group. The results of this research indicate that the consumption of fermented foods has the potential to improve cardiometabolic health.

Fermented Foods and Weight Management

Some evidence suggests that by improving the balance and diversity of the gut microbiota, the consumption of fermented foods is associated with a lower risk of obesity. An imbalance in the gut microbiota (dysbiosis) can lead to chronic inflammation and increased intestinal permeability, two factors that can promote fat storage. The metabolites produced by the bacteria in fermented foods appear to influence the genes and hormones that control fat storage, insulin sensitivity, and appetite. In animal studies and small human studies, the intake of some fermented foods has been associated with reduced weight gain, body fat, or stored fat, but larger, longer-term studies in humans are needed to confirm these effects.

Studies have shown that kimchi and lactic acid bacteria derived from it may exert anti-obesity effects in animals and humans. These effects are thought to be attributable to the modulation of lipid metabolism and several enzymes in the liver and adipose tissue, as well as various serum biomarkers. Increased levels of Akkermansia, Lactobacillus, and Bifidobacterium in the gut microbiota (which are beneficial bacteria), maintaining a balanced ratio between Bacteroidetes and Firmicutes, promoting the production of short-chain fatty acids, and repairing intestinal permeability are all processes that may contribute to the anti-obesity benefits of kimchi. However, it appears that the effects of lactic acid bacteria and kimchi metabolites are dose-dependent and strain-specific.

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Author

Kathryn Adel

Kathryn holds a Bachelor Degree in Nutrition as well as a Bachelor and a Master Degree in Kinesiology, all from Laval University. She is a Registered Dietitian and active member of the Ordre professionnel des Diététistes Nutritionnistes du Québec (ODNQ) and of the American Academy of Nutrition and Dietetics. She holds the Monash University's certification for the FODMAP diet and IBS, and has considerable clinical experience in that area. She is also an accomplished athlete, having ran track and cross-country at a national level. Kathryn specializes in sports nutrition, weight loss, diabetes, as well as heart and gastrointestinal health.