Gut bacteria signal to brain when you are full

The research may explain why some foods don’t make people feel full earlier as compared with other foods. About 100 trillion bacteria, viruses and fungi live in and on every body surface, from your eyelids to your intestines. This shouldn’t leave you anxious as the majority of these microscopic squatters are not meant for creating troubles for their host.

The place in the human body which hosts the highest number of microbial organism is the digestive system.

When you push away your plate, loosen your belt and announce, “I couldn’t manage another bite!” it may be your gut microbes talking, according to a new study. In fact, as many as a billion new E. coli bacteria may come into being during one of those feeding frenzies. By doing so, the microbes will be able to control their population. So the researchers looked for signs of change in E. coli activity relative to feeding.

Don’t have room for dessert? Different signals are sent to the brain depending on the balance or imbalance of bacteria in the gut. But a recent study suggests that you are full when your gut bacteria say so. According to a press release, the same researchers did experiments on rats and mice and noticed that their brains reduced their appetite.

The new evidence coexists with current models of appetite control, which involve hormones from the gut signaling to brain circuits when we’re hungry or done eating.

The study reveals that bacterial proteins produced by satiated E. coli control the release of gut-brain signals as well as activate appetite-regulated neurons in the brain.

Eating meals introduces nutrients to gut bacteria, and the bacteria responds by dividing and replacing units that were lost in the stool development process.

The researchers found that after 20 minutes of consuming nutrients and expanding numbers, E coli bacteria from the gut produce different kinds of proteins than they did before their feeding.

It takes about the same amount of time for a person to start feeling full or exhausted after a meal – and this is no coincidence, the researchers discovered. “We’re full.” Meanwhile, mice injected with the E. coli proteins over the course of a week ate less at each meal (though they compensated by eating more often.) All of which suggests that the proteins put out by bacteria can influence-and even interfere with-our sense of feeling stuffed.

Further analysis showed that “full” bacterial proteins stimulated the release of peptide YY, a hormone associated with satiety, while “hungry” bacterial hormones did not. The opposite was true for glucagon-like peptide-1 (GLP-1), a hormone known to stimulate insulin release. For example, last year, another group of scientists found out that microbes manipulate not only how much we eat by producing satiety hormones but also influence reward pathways into the brain by producing toxins that alter our moods and hijack our taste receptors. Hence, these bacteria produce proteins that are present in the blood in the long term and adjust pathways in the brain.