Illustration: Benny Box

Intestinal bacteria and their genetics determine dietary advice

Biotechnology and biochemistry Bacteria and microorganisms Biological systems Genes and genomes Nutrition and dietary habits Health-promoting compounds
Dietary advice should be more personalized and based on knowledge of the composition of the individual person’s intestinal bacteria.

The official dietary recommendations are still to ensure a varied diet, to eat more fish, and to cut down on salt consumption. But in the world of intestinal bacteria, it is far from given that this makes a positive difference. The composition of bacteria in your intestine and their genes are decisive to whether it’s healthy to eat broccoli, an ice cream, or an apple, says newly appointed Professor Susanne Brix Pedersen from DTU Bioengineering

“Research into how intestinal bacteria respond to different types of diet opens up for a personal approach to nutrition and health. We’re therefore trying to understand the significance of the interaction between diet and the response patterns of intestinal bacteria in the individual person, and how this is related to health and the development of various lifestyle diseases. We use this knowledge to prepare strategies for whether you can prevent disease—or even cure it—by increasing the activity of certain specific bacterial groups,” says Susanne Brix Pedersen.

Profile of healthy intestinal bacteria
The research into intestinal bacteria is being conducted by 15 researchers and students in Susanne Brix Pedersen’s research group Disease Systems Immunology.

In 75 current research projects, the researchers are studying the processes involving how the food we eat as individuals is converted by intestinal bacteria, and how they can assimilate, digest, and produce substances known to be beneficial to health.

The researchers particularly focus on diseases such as diabetes, obesity, asthma, and a number of inflammatory conditions, for which there is a documented correlation with diet, lifestyle, and genetic factors.

“Today, we don’t know everything about what defines a healthy intestinal microbiota, which can help prevent that we develop these diseases. Our research is therefore aimed at identifying what defines a wide variety of diseases, to enable us subsequently to take a step back and describe—based on the large amount of data—what defines a healthy intestine. We’re all different, so there will be differences from person to person, but—in the long term—we would like to contribute to describing the characteristic features of a healthy bacterial microbiota in the intestine, and the dietary recommendations which can be given to different groups based on this knowledge,” says Susanne Brix Pedersen.

In some projects, the researchers are—together with clinical partners—studying asthma in children and looking at differences in the immune defence system. The research has not been published yet, but Susanne Brix Pedersen explains that the researchers have ascertained which immune cells are activated many years before the onset of the disease. It is too early to say anything about whether this may be due to the mother’s diet or other exposure of the child in early life.

Diet and lifestyle
In addition, the researchers are looking at the importance of diet to intestinal inflammatory conditions in connection with obesity and type 2 diabetes, and in connection with functional diseases, including chronic fatigue syndrome. And, finally, the researchers are studying possible correlations between diet, intestinal bacteria, lifestyle, sleep, and exercise and mental disorders such as schizophrenia, depression, and autism in a collaboration with external partners.

Susanne Brix Pedersen stresses that although the correlation between intestinal bacteria and diseases is complex, it is possible to derive specific dietary advice.

“Our research shows a correlation between dietary fibres and the presence of some intestinal bacteria which we see in healthy persons. So the simple message is that it’s good for you to have a high-fibre diet with broccoli and whole grain products, and to cut down on meat,” says Susanne Brix Pedersen.