Obesity changes how our body uses energy and how sensitive our cells are to insulin. Some medicines called “anti-obesity drugs” help with obesity, especially in the USA. Researchers at the Max Planck Institute in Germany looked at people with obesity.
Researchers found that these people have trouble learning specific associations because their cells don’t react well to insulin. But when they took a medicine called liraglutide, things got better. This medicine not only helps with weight, but it also makes it easier for them to learn something.
For making choices, brains need to connect things. Like when we see a red-hot plate, we know it’s hot and can burn us. This connection of things in our brain is called associative learning. It helps us understand what happens after we do something.
The part of our brain responsible for this is the “dopaminergic midbrain.” This area has many spots for insulin and other chemicals our body uses. It helps our brain adapt to what our body needs.
But what if obesity makes the body less sensitive to insulin? Does this affect how the brain works, how we learn things, and how we behave? Scientists at the Max Planck Institute for Metabolism Research wanted to find out. They studied how well people with average weight (30 volunteers) and people with obesity (24 volunteers) learned associations. They also looked into whether the anti-obesity drug liraglutide impacted this learning process.
In the evening, they gave the participants an injection. Some got the drug liraglutide, which activates a part of the body that makes insulin and helps with feeling full. This drug is used to treat obesity and diabetes, taken once a day. The next morning, the participants had to do a learning task. This helped the researchers see how well they learn associations in their brains.
Researchers found that people with obesity didn’t connect things as well as those with average weight. Their brains also weren’t as active in the areas linked to this kind of learning.
After taking just one dose of liraglutide, the people with obesity did better in the task, and their brain activity was similar to those with average weight. It was as if the drug made their brains work like those of people with moderate weight.
These findings are significant. Researchers show that simple things we learn depend on how our body is doing. If we’re overweight, it affects how our brain learns and what we’re motivated to do. The drug helped people with obesity understand better, which matches with other studies that say this drug can make people feel full and eat less.
But it’s also concerning. Even young people with obesity, without other medical problems, had changes in how their brains work. It means we should focus more on stopping obesity in the first place rather than relying on medicine later on. This study’s leader, Marc Tittgemeyer, said, “it’s better to prevent obesity and its problems than to use medication for a lifetime.” Ruth Hanßen, who worked on the study, adds that “we need to think more about preventing obesity and its effects in the future.”
Journal Reference:
- Hanssen, R., Rigoux, L., Kuzmanovic, B. et al. Liraglutide restores impaired associative learning in individuals with obesity. Nature Metabolism. DOI:10.1038/s42255-023-00859-y.