Illustration: Benny Box

Dietary advice depends on gut bacteria and genetics

Bioteknologi og biokemi Bakterier og mikroorganismer Gener og genomer Fødevarer, fisk og landbrug Ernæring og kostvaner
Dietary advice should be more personal and based on knowledge of the composition of the individual's intestinal bacteria, says newly appointed DTU professor Susanne Brix Pedersen.

The official dietary advice is still eating varied, eating more fish and cutting down on salt consumption, but in the world of intestinal bacteria, it is far from certain that it makes a positive difference. The composition of bacteria in the gut and their genes is crucial for whether it is healthy to eat broccoli, ice cream or an apple, says Professor Susanne Brix Pedersen from DTU Bioengineering.

"The research into the reaction of intestinal bacteria to different types of diet opens up a personal approach to nutrition and health. We try to understand the importance of the interaction between diet and bacteria's response patterns in the individual in relation to health and the development of various lifestyle diseases. We use the knowledge to make strategies for preventing disease, or even curing it by increasing the activity of specific bacterial groups.”

Profile of healthy intestinal bacteria

The research in intestinal bacteria is performed by 15 researchers and students in Susanne Brix Pedersen's research group Disease Systems Immunology. In 75 current research projects, the researchers investigate the processes in how what we eat as individuals are translated by bacteria in the gut, and how they can absorb, digest and produce substances that are known to promote health. The researchers have a particular focus on diseases such as diabetes, obesity, asthma and a number of inflammatory conditions, where there is a documented relationship with diet, lifestyle and genetic factors.

“Today we do not know all about what defines a healthy intestinal microbiota, which can help prevent us from getting these diseases. Our research is therefore aimed at mapping what defines a wide variety of disease states, and then to step back and describe, based on the many data, what defines a healthy gut. We are all different, so there will be differences from person to person, but in the long run, we would like to help describe what characterizes a healthy bacterial microbiota in the intestine, and which dietary advice it can give rise to in different groupings of people, ”says Susanne Brix Pedersen.

In some projects, the researchers, together with clinical partners, examine asthma in children and look at differences in the immune system. The research has not yet been published, but Susanne Brix Pedersen explains that the researchers have found the immune cells that are being activated, many years before the disease brakes out. It is still too early to determine whether this is caused by the mother's diet or other exposure of the child in early life.

Diet and lifestyle

In addition, the researchers study the importance of diet in inflammatory conditions in the intestine in connection with overweight and type 2 diabetes and functional diseases, including chronic fatigue syndrome. Finally, in collaboration with external partners, they examine the possible relationships between diet, intestinal bacteria, lifestyle, sleep and exercise and mental illnesses such as schizophrenia, depression and autism.

Susanne Brix Pedersen emphasizes that although the connection between intestinal bacteria and diseases is complex, it is possible to derive concrete dietary advice. "Our research shows a relationship between dietary fiber and the presence of intestinal bacteria that we see in healthy people. Therefore, in its simplicity, the message is that it is useful to eat high fiber foods such as broccoli and whole grains and to cut down on the meat. It is entirely in line with TV2's series "Spis dig rask” (“Eat your way to health”, ed.)", where a number of subjects change their lifestyle and reduce their medication consumption dramatically in 12 weeks," says Susanne Brix Pedersen