ICN 2017, Buenos Aires, Argentina

The Role of Fermentation Products in the Health Effects of Yogurt

Yogurt-fermentation-peptides-health benefits

Numerous epidemiological studies reported that yogurt consumption may be used as a new biomarker of a healthy lifestyle. What could explain the health benefits of yogurt? At the 5th Yogurt Summit, held in Buenos Aires (Argentina) on October 18th, Dr André Marette (Laval University, Québec) presented up-to-date evidence on bioactive compounds produced during fermentation.

Yogurt consumption has been associated with healthy dietary patterns and lifestyles, better diet quality and healthier metabolic profiles. Studies have shown that frequent yogurt consumers do not only have higher nutrient intakes, but also an improved diet quality, which includes higher consumption of fruits and vegetables, whole grains, and dairy products compared with low or non-consumers. This indicates better compliance with dietary guidelines. Dr Marette summarized recent epidemiological and clinical evidence, which also suggests that yogurt contributes to better metabolic health.

Cardiovascular Diseases, Type 2 Diabetes and Obesity

Strong consistent evidence from multiple meta-analysis on the association between yogurt intake and the risk of Type 2 Diabetes (T2D) reported consistent results. Hence, several studies suggest that there is high-quality evidence that supports an inverse association between the intake of yogurt and the risk of T2D. However, to date, there have been few to no randomized clinical trials (RCT), investigating yogurt intake in relation to cardiometabolic clinical outcomes. Therefore, we cannot determine a causal link.

Evidence also suggests that the association between yogurt consumption and CVD risk, as well as for coronary artery disease, hypertension and stroke, is neutral and this assessment is based on moderate-quality evidence.

In a recent systematic review, all epidemiological studies found an association between yogurt consumption and lower body mass index, lower body weight/weight gain, smaller waist circumference and lower body fat. The authors suggest an important role for yogurt in weight management, but cannot determine a cause-effect relationship.

Last but not least, there is a limited number of prospective cohort studies and no meta-analysis on the association between yogurt consumption and MetS (Metabolic Syndrome) risk. The quality of the evidence, relating yogurt intake to the incidence of MetS, is judged to be very low, and thus the association remains uncertain.

The Role of Ferments and Fermentation by-products (bioactive peptides)

In his presentation, Dr Marette also focused on recent evidence showing that dietary proteins are key regulators of immunometabolic factors and the gut microbiota. In addition, fermentation with bacterial strains generates bioactive peptides from dairy proteins resulting in a potentially greater beneficial effect of yogurt on metabolic health compared with non-fermented dairy products such as milk. He specifically outlined potential mechanisms, observed in recent animal studies, that could underlie the inverse associations between yogurt intake and incidence of cardiometabolic diseases (CMD) and these mechanisms seem to be related to its bacterial constituents and bioactive peptides released during fermentation. For example, data suggests that these bioactive peptides have physiological effects such as increased insulin sensitivity and glucose tolerance.

It seems that fermented dairy peptides and especially yogurt-type peptides also exerted greater anti-inflammatory effects (on intestinal inflammation and metabolic endotoxemia) than other dairy products. These immunometabolic effects are associated with taxonomic changes in the gut microbiota. Hence, microbes in fermented foods may contribute to human health in a manner similar to probiotics. However, whether specific bacterial species are modulated by peptides released during lactic fermentation remains to be determined.

In conclusion, these newly proposed mechanisms are surely promising, but require more research before being validated as a key factor in the protection against CMD, like type 2 diabetes or obesity.

Highlights

·       Yogurt consumption may be considered a signature of a healthy diet through its nutritional content, impact on metabolic health including the control of energy balance, body weight and glycemia and its relationships with healthier behaviours and lifestyle factors.

·       Fermented dairy products, like yogurt, generally exert greater metabolic and anti-inflammatory effects.

·       These immunometabolic effects are associated with taxonomic changes in the gut microbiota.

·       Peptides released during fermentation may explain some of the health benefits of yogurt consumption on cardiometabolic diseases