Scientists are still trying to understand how the body knows which nutrients it is lacking.
A new study published in Science suggests that the gut plays a much larger role in this process than previously thought.
A research team from the Institute for Basic Science, Seoul National University, and Ewha Womans University investigated how the body responds when it lacks protein, which is essential for building and maintaining the body.
More than digestion
The researchers used fruit flies in their experiments. They found that the gut not only helps with digestion but also monitors the body's nutritional needs.
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When essential amino acids derived from protein are lacking, the gut sends signals to the brain. This occurs both through the nervous system and via hormones circulating in the bloodstream.
According to the researchers, these signals help the body respond to nutrient deficiencies.
Gut bacteria play a role
The study also showed that gut bacteria play an important role.
Fruit flies without their normal gut microbiota reacted more strongly to amino acid deficiencies than other flies.
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The researchers therefore believe that bacteria in the gut can influence eating habits by altering the signals sent between the gut and the brain.
Experiments in mice
Experiments in mice produced similar results, suggesting that the mechanism is not limited to insects but is also present in mammals.
When the body lacks protein, the gut activates a system that causes the brain to prioritize protein-rich foods. At the same time, interest in sugar decreases.
Sources: SciTechDaily and Science.
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