IATA publishes in "Nature" a study that claims that the gut microbiome conditions the effects of diet on the body and determines its impact on health

The gut microbiome, the set of microorganisms that inhabit the intestine and its genomes, acts as a fundamental intermediary between diet and health. A review published in the journal Nature Reviews Gastroenterology & Hepatology delves into this connection and explores how food influences the composition and functions of these microbial communities and, in turn, how these micro-organisms modify the health properties of the diet, with effects on the metabolism, immune and nervous systems. Yolanda Sanz, researcher at the Institute of Agrochemistry and Food Technology (IATA), located in the scientific-academic area of the Science Park University of Valencia (PCUV) and Severo Ochoa centre of excellence under the Higher Council for Scientific Research (CSIC), leads this work, carried out together with an international team of specialists in nutrition, microbiology, immunology and neurobiology. 

The study shows that a diet with an inadequate supply of nutrients negatively affects the diversity and functions of the microbiome, with negative consequences for physiological processes such as immune response, cognitive functions or control of energy metabolism. This relationship is bidirectional, as the microbiome also modifies the nutritional value and quality of the diet through digestion and transformation of its components into other bioactive compounds, which in turn determine their effects on health. 

"The gut microbiome is a key modulator of dietary effects on various aspects of our health. Understanding how it influences the response to different foods, diets and eating habits is essential for designing more effective nutritional strategies", Yolanda Sanz, researcher of the Microbiome and Innovation in Nutrition and Health group at IATA-CSIC and lead author of the article

This finding is key to understanding the causes of individual variability in responses to the same diet and will contribute to the design of more effective and personalized nutritional strategies, highlight the authors. 

Good and bad for the microbiome

The work identifies nutrients, foods and food groups with most evidence of positive impact on the gut microbiome, including fruits, vegetables, legumes, nuts and fermented foods. It also highlights that the content of fiber and protein in the diet is one of the factors that has a major impact on the microbiome. Conversely, excessive consumption of foods high in fat, sugar or salt (characteristic of ultra-processed products) is associated with adverse effects such as reduced microbial diversity, metabolic alterations and inflammation. 

Habits like meal schedules can affect the impact of the microbiome on digestion, immune response and hormones that regulate metabolism. Eating at irregular hours, for example, can alter the production of bacterial molecules that influence lipid absorption regulation, which could lead to increased body fat accumulation. "The gut microbiome is a key modulator of dietary effects on various aspects of our health. Understanding how it affects the response to different foods, diets and eating habits is crucial for designing more effective nutritional strategies," says Yolanda Sanz, researcher at IATA-CSIC’s Microbiome and Innovation in Nutrition and Health group and lead author of the article.

Between food and organs

Gut bacteria act as a key link between diet and the different organs and systems of the human body that are influenced by nutrients. The metabolites that the gut microbiome produces from food, in coordination with organs such as the liver, regulate metabolism and functions of the immune, endocrine and nervous systems. 

At the immunological level, the microbiome strengthens the intestinal barrier and regulates inflammatory responses, thanks to compounds such as indoles, which are generated from the diet. In the nervous system, it acts on the gut-brain axis by strengthening the blood-brain barrier function and participating in mood regulation by influencing the production of substances such as serotonin, dopamine or gamma-aminobutyric acid (GABA). In the cardiometabolic domain, the microbiome helps regulate appetite, glycemia and inflammatory response, especially in high-calorie diet contexts. It does so partly through the compounds produced by fermenting dietary fibre, such as short-chain fatty acids, or by metabolizing amino acids, such as tryptophan, which give rise to substances with beneficial functions, such as indolacetic acid or indole propionic acid.

"Despite important advances in microbiome science, its integration into nutritional and clinical practice is still very limited. Current recommendations are a good starting point, but could be improved in the future by taking into account the heterogeneity of the population and adapting the diet to the individual microbiome for more effective interventions, similar to the advances applied in personalized medicine", Yolanda Sanz, researcher of the Microbiome and Innovation in Nutrition and Health group of IATA-CSIC and lead author of the article

The study raises the need to update dietary guidelines as knowledge about the role of the microbiome in the health effects of food grows. Although current recommendations promote beneficial habits for the general population (consumption of fruits, vegetables, legumes and low-processed foods associated with a healthy microbiota), do not yet incorporate specific criteria that consider biological variability between individuals.

Towards personalized nutrition

For example, some people produce higher amounts of trimethylamine oxide (TMAO), a substance derived from microbial metabolism linked to an increased risk of cardiovascular disease. In these cases, a diet low in red meat, eggs or dairy products containing precursors of these compounds could be helpful. On the other hand, foods rich in fiber, beneficial for most, can have adverse effects on people with inflammatory bowel diseases, which reinforces the idea that the diet should be adapted to each individual. 

"Despite important advances in microbiome science, its integration into nutritional and clinical practice is still very limited. Current recommendations are a good starting point, but could be improved in the future by taking into account the heterogeneity of the population and adapting the diet to the individual microbiome for more effective interventions, in a similar way to the advances applied in personalized medicine," says the IATA-CSIC researcher.

 

Don’t miss our R&D+ video on the intestinal microbiota and Covid-19, with an explanation by Yolanda Sanz, IATA researcher

 

Source: CSIC Delegation Comunitat Valenciana