Traditional Sardinian Fermented Milk Boosts Gut Health by Reshaping Microbiota

Ancient Sardinian Fermented Milk Shows Promise for Gut Health

Fermented foods have been part of human diets for thousands of years, offering flavor, preservation, and health benefits. Now, modern science is uncovering how these traditional foods influence our gut microbiota, the vast community of microbes living in our digestive systems.

A recent study focused on casu axedu, a traditional Sardinian fermented milk still consumed in Italy’s Blue Zones—regions famous for exceptional longevity. Using 16S rRNA gene sequencing and metaproteomics, researchers discovered that casu axedu reshapes gut microbiota composition, boosts beneficial bacterial functions, and reduces inflammation in a controlled rat model.

Study Design: A Multi-Omics Approach

For eight weeks, researchers fed rats either a standard diet or one supplemented with casu axedu. They then analyzed:

Gut microbiota composition via 16S rRNA gene sequencing
Bacterial metabolic functions via shotgun metaproteomics
Host inflammatory markers in colonic contents

This integrated approach provided insights into both which bacteria changed and what they were doing metabolically.

Key Findings: Microbial and Metabolic Shifts

1. Enrichment of Beneficial Bacteria

Casu axedu consumption significantly increased:

Prevotella – associated with carbohydrate metabolism and fiber fermentation
Phascolarctobacterium – linked to propionate production, beneficial for colon health
Blautia glucerasea – known for anti-inflammatory properties
Lactococcus lactis – a probiotic species naturally present in the fermented milk

Conversely, Bacteroides dorei and Helicobacter rodentium, often linked to inflammation, decreased.

2. Enhanced Metabolic Activity

Metaproteomics revealed:

Higher glycolytic activity in Prevotella through the Embden-Meyerhof-Parnas pathway
Increased succinate production, fueling Phascolarctobacterium to produce propionate, a short-chain fatty acid with anti-inflammatory effects
Greater synthesis of branched-chain amino acids (BCAAs) like L-valine and L-leucine, important for host metabolism

3. Reduced Inflammation and Virulence Factors

Notably, rats consuming casu axedu showed:

Lower levels of bacterial virulence proteins
Reduced host inflammatory markers, including C-reactive protein (CRP) and tissue kallikrein, both associated with gut inflammation

These findings suggest fermented milk supports a healthier gut environment by enriching beneficial microbes and dampening pro-inflammatory signals.

Why It Matters: From Sardinia to the World

Sardinia’s Blue Zone diet has long been linked to longevity and metabolic health. This study provides mechanistic evidence for how one of its staple foods—casu axedu—could:

Support gut microbial diversity
Enhance short-chain fatty acid production
Reduce gut inflammation

Such effects align with growing evidence that fermented foods act as natural probiotics, promoting metabolic and immune health.

Conclusion: Fermented Foods for a Healthier Gut

The research highlights traditional fermented milk as a potential functional food for improving gut microbiota composition and metabolic function. While further human studies are needed, casu axedu and similar fermented foods may offer accessible dietary tools for promoting gut and overall health.

Reference

Abbondio, M., Palomba, A., Serra, M., Fraumene, C., Di Meo, C., Marongiu, F., Sau, R., Pagnozzi, D., Laconi, E., Tanca, A., & Uzzau, S. (2025). Consumption of traditional Sardinian fermented milk promotes changes in the rat gut microbiota composition and functions. BMC Microbiology, 25(1), 578. https://doi.org/10.1186/s12866-025-04333-5