This post has been written by Guillermo Mena-Sanchez and co-authored by Nancy Babio and Jordi Salas-Salvadó, from published article Mena-Sánchez G, Babio N, Martínez-González MÁ, et al. Fermented dairy products, diet quality, and cardio-metabolic profile of a Mediterranean cohort at high cardiovascular riskNutr Metab Cardiovasc Dis. 2018; 28(10):1002-11. doi: 10.1016/j.numecd.2018.05.006.

Fermented foods have been used for thousands of years and they come about through extensive microbial growth. These foods are known for improving shelf life, safety and organoleptic and nutritional properties when compared with the original food substrates. Furthermore, fermented foods that retain living cultures (e.g. yogurt and some cheeses) may reduce the risk of some diseases. Although the impact of fermented foods on human health enjoys a positive perception, well designed studies that objectively evaluate their health benefits remain scarce.

A new cross-sectional study, led by researchers from CIBEROBN centre at the Universitat Rovira i Virgili in Tarragona (Spain) in collaboration with another 23 research groups from the PREDIMED-Plus clinical trial, has found that consuming fermented dairy products is associated with a healthier life-style and greater adherence to the Mediterranean Diet.

This observational study evaluated the associations between consuming fermented dairy products, diet quality and the prevalence of metabolic syndrome (MetS) components in 6,572 Mediterranean men and women (mean age 65 years) who were overweight or obese and suffered from MetS.

Participants who consumed higher amounts of fermented dairy products and especially yogurt showed greater adherence to the Mediterranean Diet. Likewise, they reported higher levels of consumption of healthy foods including fruit, vegetables, fish, nuts and wholemeal bread, while consuming lower levels of white bread, alcohol and cookies. These participants also smoked less, which suggests that consuming fermented dairy products is a possible marker of a healthy lifestyle.

In line with these findings, another previous study by our research group found that yogurt consumption is inversely associated with a lower risk of metabolic syndrome (MetS) incidence, which supports yogurt consumption as a diet quality indicator. These data also add to previous studies supporting the beneficial effect of yogurt on risk factors for type 2 diabetes.

Meanwhile, high levels of cheese consumption were associated with a low risk of hypertriglyceridemia and low HDL-cholesterol plasma levels. These results were observed when comparing participants located in the highest quartile of cheese consumption (±50 grams/day) with those who consumed smaller amounts of cheese. In the case of yogurt consumption, total, low and whole-fat yogurt intake was not associated with any of the MetS components.

The results obtained in this observational study can be explained by the intrinsic components of fermented dairy products. Yogurt and cheese are actually nutritionally dense foods, with a matrix of nutrients that make them unique. These fermented dairy products, and especially cheese, typically have a high content of good quality protein and calcium bioavailability. Fermented dairy products also typically contain other sources of minerals, vitamins and bacteria with potential benefits for human health. Furthermore, the increased bioavailability of insulinotropic amino acids and peptides, as well as the bacterial biosynthesis of vitamin K2, have been proposed as potential mechanisms that explain the results of this observational study.

As we did not analyze participants’ gut microbiota in the study, we are not familiar with the role played by cheese and yogurt bacterial strains in modulating the gut microbiota as a mechanism of action. However, adherence to the Mediterranean Diet was recently associated with higher bifidobacterial counts and higher levels of total short-chain fatty acids, which might explain the gut microbiota’s partial role in mediating the Mediterranean Diet’s health benefits.

The different ways the studies looking at fermented dairy products have been designed means we cannot elucidate how fermented foods contribute to human health. Clinical trials and large prospective epidemiological studies are required to confirm our findings, along with studies specifically designed to address the impact of food fermentation on health outcomes.