The term microbiota refers to the trillions of microorganisms –bacteria, viruses, fungi, archaea and protozoa– that reside in our bodies. Most of these are found in the digestive tract, where they are referred to as gut microbiota. Many of these microorganisms, which have evolved alongside us over millions of years, perform vital functions such as digesting food, producing vitamins, defending against pathogens and regulating the immune system.
The composition of each person’s gut microbiota is unique and varies according to factors such as age, genetics, dietary habits, environment, lifestyle and medication use. A diverse and balanced microbiota is essential for maintaining health.
Since the middle of the last century there has been a growing interest in understanding and studying the community of microorganisms that inhabit the human gut and the role they play. Initially, they were thought to be pathogenic organisms, meaning harmful to humans. However, scientific advances have made it possible to establish the symbiotic relationship we share with them.
Recently, science has gone a step further and new fields of study have opened up. Researchers point out that there is a two-way communication between the gut microbiota and the central nervous system and brain, known as the microbiota-gut-brain axis. This axis, which enables communication between these two systems, influences both mental and physical health.
In recent years, numerous studies have been published linking certain imbalances in the gut microbiota with obesity, diabetes and asthma. There is evidence that these microorganisms may influence our behaviour and mood. It has also been observed that people with conditions such as depression, Alzheimer’s, Parkinson’s or even autism often exhibit alterations in the composition of their microbiota.
Together with three researchers working in this field –Marc Claret, Carlos Ribeiro and Mireia Vallès-Colomer– we will attempt to address some key issues in this debate: How does the microbiota-gut-brain axis work? How do they communicate? What influence does the microbiota have on appetite and metabolism? Is there a relationship between gut microbiota and mental health? What is understood by a healthy gut microbiota? What should the public know in order to take care of their microbiota?
Obesity is one of the main public health problems on a global scale. In Spain, it affects one in five adults and is increasing at a rate of 0.50 % per year. A better understanding of the mechanisms behind this epidemic is essential to develop new therapies. In recent years, research has focused on the role of the microbiota in the development of obesity and diabetes by analysing its possible influence on the regulation of appetite and metabolism. However, less attention has been paid to how the brain affects the microbiota. The team led by Marc Claret has investigated this relationship with the aim of understanding the molecular mechanisms by which the hypothalamus, a region of the brain that regulates energy balance, modulates the composition of the microbiota and gut function.
The food we eat has a significant impact on our mood and behaviour. Recent studies have shown that the relationship between diet and brain function is mediated by the gut microbiota. Carlos Ribeiro and his team are investigating the brain mechanisms involved in food decision-making. Using the fruit fly as an animal model, they have succeeded in demonstrating for the first time that the interaction between nutrients and gut microbiota affects neuronal communication and influences appetite and dietary preferences. These findings open up new perspectives for a better understanding of the interconnection between microbiota, diet and the brain, which is key to maintaining the body’s health.
Microbiologist Mireia Vallès Colomer is an expert in the study of the impact of the gut microbiome on health. Through her research, she has established a link between mental health issues and the gut microbiome by identifying differences in bacterial compositions between people with depression and healthy people. However, it is complicated to determine causality, since alterations in the microbiome could be both a cause and a consequence of the disease. She has also found that the gut microbiota is transmitted not only from mother to child, but also between people living together.
Speakers:
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Marc Claret, leader of the Neuronal Control of Metabolism research group at the Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS).
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Carlos Ribeiro, leader of the Behavior and Metabolism research group, at the Champalimaud Centre for the Unknown.
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Mireia Vallès Colomer, principal investigator of the Microbiome Research Group, at the Universitat Pompeu Fabra (UPF).
Moderator:
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Cristina Sáez, health and science journalist.
Projects supported by CaixaResearch:
