European MyNewGut project coordinated by IATA identifies gut bacteria to combat obesity and stress

  • The MyNewGut project, coordinated by IATA, shows the influence of the intestinal microbiota on the energy balance that regulates body weight and brain function.
  • Identified bacteria may lead to new probiotics to combat obesity and stress, and their complications, such as metabolic syndrome and depression.

The intestinal microbiota (the community of microorganisms that inhabits the digestive system) plays a key role in our organism: it influences the development and functioning of the immune, endocrine and nervous systems. Now, a European project coordinated by researchers from the Spanish National Research Council (CSIC) has shown that a healthy microbiote contributes to regulating appetite, metabolism of nutrients such as glucose, body weight and inflammation associated with obesity. It also demonstrates the influence of microbiota on neurodevelopment and the response to stress, which in turn influences the future risk of developing chronic metabolic and mental pathologies.

The project has identified new intestinal bacterial strains that could lead to a new generation of probiotics capable of more effectively combating chronic pathologies associated with obesity and stress, such as metabolic syndrome and diabetes, and depression.

This project, called MyNewGut (Microbiome Influence on Energy Balance and Brain Development Function into Action to Tackle Diet-Related Diseases and Behaviour), has been funded by the European Union with nine million euros and coordinated by the CSIC researcher Yolanda Sanz, head of the Microbial Ecology, Nutrition and Health group at the Institute of Agrochemistry and Food Technology (IATA) in Valencia. This initiative has revealed important findings on how intestinal microbiota regulates nutrient metabolism and energy balance in the human body, and on how diet, through its influence on microbiota, can contribute to reducing the risk of diseases associated with obesity and stress.

The microbiota can help to reduce the development of obesity

"In this project we have identified the characteristics of the intestinal microbiota that, together with the diet, contribute to the risk of developing obesity and its comorbidities, and that can help us to predict it and thus be able to establish preventive dietary strategies at an early stage. Specifically, "in one of our studies we observed that an unhealthy diet reduced the diversity of the microbiota and increased the abundance of potentially inflammatory proteobacteria (enterobacteria) in children who were initially of normal weight and who developed overweight during the study period (4 years). On the contrary, in children who maintained a normal weight, reductions in this group of bacteria were observed," explains Sanz.

Healthy microbiota helps control intake

In another intervention study, the microbiota has been transferred from healthy donors to individuals with metabolic syndrome, by fecal transplantation. This has shown that a healthy microbiote increases the expression of the brain's dopamine receptor, increasing appetite control and reducing intake. "The findings show for the first time in humans that the intestinal microbiota has a favourable influence on the control of the energy balance and thus improves metabolic health, regulating the intestinal-brain axis", explains Professor Sanz.

The MyNewGut team has also investigated both the effects of the amount of proteins in the diet and the type of proteins (of animal origin such as casein or vegetable such as soy proteins) in overweight volunteers. "Although diets rich in proteins are often effective in losing weight, the increase in protein intake also increases the proportion of protein products that reach the large intestine and are metabolized by the microbiota of the colon, generating toxic compounds," explains Sanz. "Our study shows, for the first time, that not only the amount of protein in the diet is important, but also its quality, and that this results in the production of a greater or lesser number of metabolites toxic to the kidney as a result of the activity of our microbiota. This should be taken into account in future recommendations on high-protein diets, especially when they are maintained for a long time," adds the researcher.

The influence of childbirth and antibiotics on stress response

Members of the MyNewGut consortium have also investigated how intestinal microbiota that are affected by lifestyle-derived environmental variables, such as type of delivery, can influence stress response. Humans have shown that young adults born by caesarean section have an exaggerated stress response compared to young adults.

In addition, they have shown that the use of antibiotics in the first days of life, in children born by caesarean section, together has a negative impact on neurodevelopment.

"This is important, given the relationship between stress and an increased risk of mental (such as depression) and metabolic (such as cardiovascular pathologies) illnesses, especially considering that the number of cesarean deliveries is increasing worldwide," he adds. In the EU the percentage of caesarean births exceeds 30%, while the WHO recommends not exceeding 12%. In experimental models, they have also shown that the microbiota is responsible for obesity-associated depression, and that its modulation (e.g. with probiotics or antibiotics) improves mood alterations.

 

"Based on all these studies, the IATA-CSIC team has generated a biobank of human intestinal bacteria, which is a valuable biological material that can be exploited to combat obesity and associated metabolic and mental complications and for other future applications in nutrition and clinical practice," concludes Sanz. Some of these bacteria demonstrate regular endocrine, neural and key immunological pathways (represented in the figure) and are the origin of new patents.