Could worms give the answer to obesity?
The humble earthworm gets far too little attention in relation to the benefits it brings to us humans. It could give us some important knowledge about the interaction between molecules and bacteria in the human intestine, according to Knut Rudi, Research Scientist at Nofima Mat.
The earthworm is a simple organism with simple model systems – one of the simplest model systems we can find in fact. But the earthworm has an intestine in which intestinal bacteria extract the nutrition from what it eats, exactly as with people. In earthworms we also find the signal molecule serotonin, which today we mainly associate with the state of mind in human beings.
Rediscovering a signal molecule
“To understand why I am researching earthworms, you need to go far back in time, perhaps as much as 5 million years. Then perhaps the forerunner of what would one day become humans had the same mechanisms as the earthworm does today. If we transfer knowledge about this simple organism to humans, we can better understand the development of our own intestinal flora,” says Knut Rudi.
He pauses, takes a deep breath and continues.
“We believe that the signal molecule serotonin functions as a mechanism that causes the earthworm to stop eating. The truth is that, if the earthworm did not have this little molecule telling it to stop eating, it would eat all the time, until it finally ate so many bacteria that it would be eaten up from inside by bacteria in the intestinal system. This molecule is therefore essential for the worm’s very existence,” explains Knut Rudi.
Connection between mental health and molecules
If we transfer this knowledge over to humans, we could assume that serotonin had the same effect on us around 500 million years ago. Today this molecule is associated with mental health. It is therefore interesting to find out more about the causal relationships.
“Could people with a weight problem have less of the serotonin molecule than others?,” asks the researcher. He is not the first researcher in the world to be fascinated by microbial communities. Charles Darwin was very interested in studying model systems in simple mechanisms like earthworms, and he became interested in how species adapted to their surroundings.
Historical development is important, Rudi believes. He thinks we human beings are concerned about what we see and give no attention to what we don’t see, even though it may be important for our health and our existence. That is why Knut Rudi believes that the humble earthworm, which is perhaps one of the oldest organisms on earth, gets far too little attention.
Knut Rudi has two jobs. At Nofima Mat, he researches into microbial communities. He looks at how microbial communities occur and how they develop. This is a wide field of research, which includes microbial communities in food and the significance of bacteria in the intestine for our health. Knut Rudi is also employed as a researcher at Hedmark University College, where he primarily researches into model systems, using the earthworm as his “guinea pig”.
“They are good experimental animals that don’t make many demands. They don’t need much food and they don’t take up much space. A box of earth makes a good long term residence, and we give them a kind of flour mixture now and then,” laughs Rudi.
About analysis of microbial communities
Analysing microbial communities involves everything from analyses of food to faecal samples from both humans and animals. Nofima Mat focuses on understanding the significance of the intestinal flora for health in both animals and humans, as well as understanding and manipulating the intestinal flora of production animals so as to reduce the extent of dangerous bacteria.
Serotonin is a signal substance in some of the connections in the nervous system. We believe that serotonin is important for regulating body temperature, humour, sleep, vomiting, sexuality and appetite. Low levels of serotonin could be a cause of clinical depression, migraine, tinnitus, fibromyalgia, bipolar disorder, compulsive disorders and anxiety disorders. Disruption of the serotonin system could also be associated with cot death. Serotonin is used in several different systems in the human body; among other things it is both important for and common in the brain and the digestive system. Serotonin is found in many medical preparations for depression.