Who smells nothing remains slim

The fact that the sense of smell contributes significantly to the enjoyment of food, knows everyone who does not taste a cold because of the stuffy nose. But as researchers from Berkley have found in experiments with mice, the smell also has an influence on the control of the energy budget.

Scientists have found that particularly smelling mice are growing faster. If the smell is switched off, as in the case of a cold, they do not increase despite a fat-rich diet.

The smell of mammals is not always the same in the course of the day. If they are hungry, the nose becomes more sensitive to facilitate the search for food. After eating, the smell then falls asleep. It is only when the hunger recalls, that the sense of smell also becomes stronger.

But what happens when the smell is completely switched off? This is what Andrew Dillin and his team asked at the University of California at Berkeley. "Our hypothesis was that if you eat a lot of calories, you naturally increase, but we wanted to know if you need to eat what you eat."

Mice that smell nothing lose body fat

Andrew Dillin examined his hypothesis in normal-weight mice, whose sense of smell was artificially eliminated. To his surprise the animals did not increase despite a fat-rich diet. Mice, which were heavily overweight before the start of the experiment, lost nearly one-fifth of their body weight by turning off the odorant, although their appetite remained the same. The weight reduction was due to the fact that the animals lost their body fat. The mass of muscles, bones and organs remained the same.

"At first, we thought that the mice simply did not eat so much, but they are born with a functioning odor and know where the food is in the cage, and when we switch off the smell, they eat normally, even without the food smell Compared to normal smelling mice, they even eat a little more per gram of body weight, which was one of the key moments in the study, and we thought, "Wow, where are all these calories going?" Of fat as with other animals, so what do the mice do with it? "

Mammals have two types of adipose tissue: white storage fat, which is under the skin as an insulating layer and surrounds the organs in the abdomen. And the so-called brown fat, into which mitochondria are embedded, consume energy and convert it into heat. These internal heaters use mice in cold or in stressful situations. And obviously, when they smell nothing more, as Andrew Dillin and his colleagues discovered.

"When we turn off the smell of the mice, they increase the activity of the brown fat, becoming almost black fat because it contains so many mitochondria, and at the same time they convert some of the white fat into brown Calories burned, but at the same time consumes the stored fat. "

Therapy approach for overweight people?

It is unclear how the failure of the olfactory power leads to this metabolism change. Andrew Dillin believes that the connection between smell perception and food intake may play a role. "Probably the following happens: Because they do not smell anything, the animals think all the time that they have just eaten and it is time to burn the calories, normal mice would go through a rhythm, the smell will become more sensitive, they will eat, the smell goes And when they get hungry, he goes back again, but with our animals he is out of control all the time, and we have probably made them think that they eat all the time, even though they do not eat it more than a few times Day. "

The food intake is controlled by the hypothalamus. This part of the brain collects information about the nutrient intake and adjusts the feeding behavior accordingly. Andrew Dillin assumes that the sense of smell communicates with the hypothalamus, and that the failure of the hypothesis disrupts the control. It also suggests that especially smelling mice grow particularly rapidly, as Andrew Dillin learned by chance.

"I told a friendly scientist about our results and he said, 'This is weird, we have smells that smell very well and they are spontaneously bold.' It is a therapeutic approach, and when we dampen their ability to smell, they can also be used as a dietary supplement, They would also lose weight. "

How the communication between Riechnerv and Hypothalamus functions exactly, the researchers therefore want to find the next.