Yogurt, kefir, kimchi… why should you include fermented foods in your diet?

Fermented foods , present in the human diet for millennia, have gained renewed interest due to their potential to improve health. In recent years, their impact on the gut microbiota, inflammation, cardiometabolic health, and other factors has been evaluated. This is due to improved availability of vitamins and minerals, and the synthesis of certain vitamins such as vitamin K. Furthermore, as part of their metabolism, they synthesize peptides, short-chain fatty acids, and organic acids, all of which have potentially beneficial effects.

Among the most common fermented foods are dairy products (yogurt, kefir, cheese), vegetables ( sauerkraut , kimchi), beverages (kombucha), and soy (tempeh, miso). The great advantage of these foods is that, in addition to their nutrient content, they provide live microorganisms, known as probiotics, which are largely responsible for their health benefits.

Regarding immune system modulation, a clinical trial by Wastyk et al. of Stanford University showed that a 10-week diet rich in fermented foods increased gut microbiota diversity and reduced inflammatory markers in healthy adults. Significant decreases were observed in inflammatory proteins, such as interleukin-6, which are linked to chronic diseases like type 2 diabetes and rheumatoid arthritis. These effects were consistent across all participants in the fermented food group.

A 2023 systematic review of plant-based fermented foods in people with metabolic syndrome, obesity, or type 2 diabetes found that 73% of studies reported significant improvements in glucose, lipid profile, blood pressure, waist circumference, body fat percentage, and C-reactive protein . Additionally, an increase in beneficial bacteria in the gut microbiota, such as Bifidobacterium and lactobacilli, and a reduction in potentially pathogenic bacteria were observed.

Another systematic review, Fermented foods and cardiometabolic health: Definitions, current evidence, and future perspectives , on fermented dairy products highlights consistent associations between their consumption and a lower risk of type 2 diabetes, colorectal and breast cancer, improved weight control, and cardiovascular health .

Fermented foods can modulate the gut microbiota both in the short and long term, as assessed in the article Health benefits and risks of fermented foods—the PIMENTO initiative , they also intervene in the production of beneficial metabolites and may contribute to the improvement of gastrointestinal symptoms, although the magnitude and duration of these effects vary depending on the food and the individual. The presence of probiotics and bioactive compounds may promote intestinal barrier integrity and reduce low-grade inflammation.

There is growing evidence supporting the positive effects of fermented foods on bone health, immune function, and infection prevention, although further human studies are needed to confirm these findings.

How can we apply this evidence in our daily lives?

• Include yogurt, kefir, kimchi, sauerkraut, miso, tempeh or kombucha in your daily diet .
• Prefer fresh, unsterilized products when safe, as they better preserve live microorganisms.
• Combine fermented foods with a high-fiber diet to enhance their effects on the gut microbiota.
• Consult a healthcare professional if you have immune or gastrointestinal conditions or are taking immunosuppressive medications before increasing your probiotic intake.

Have questions about which fermented foods are best for you? Always consult a dietitian-nutritionist to tailor recommendations to your personal needs.

Fermented foods , present in the human diet for millennia, have gained renewed interest due to their potential to improve health. In recent years, their impact on the gut microbiota, inflammation, cardiometabolic health, and other factors has been evaluated. This is due to improved availability of vitamins and minerals, and the synthesis of certain vitamins such as vitamin K. Furthermore, as part of their metabolism, they synthesize peptides, short-chain fatty acids, and organic acids, all of which have potentially beneficial effects.