For people who where wondering how this would even work on a technical level, the article contains a few pleasantly concrete examples:
> When the researchers investigated the microbiomes of [mice who avoid social contact], they found the animals lacked a common species called Lactobacillus reuteri. When they added a strain of that bacteria to the diet, the animals became social again.
Dr. Costa-Mattioli found evidence that L. reuteri releases compounds that send a signal to nerve endings in the intestines. The vagus nerve sends these signals from the gut to the brain, where they alter production of a hormone called oxytocin that promotes social bonds.
Other microbial species also send signals along the vagus nerve, it turns out. Still others communicate with the brain via the bloodstream.
One of the many chemicals that your gut bacteria produce is butyrate, a short chain fatty acid. Butyrate has many uses in your body, including feeding other gut bacteria, feeding the epithelial cells in your intestines, has anti inflammatory properties, used as a neurotransmitter, and encourages the production of growth hormones. Your gut bacteria also produce a number of other chemicals, including many vitamins.
There are at least 400 different species living in a healthy person's gut (it's difficult to define a species, since they transfer dna between themselves.) Many of these we haven't been able to successfully grow in a lab. Their primary food is resistant starch, which is starch that your small intestines can't split apart and absorb. There are a number of different types of resistant starch, which basically comes down to how the chains of glucose and fructose molecules are arranged. Different bacteria prefer different types of resistant starch, and thus you can majorly influence your biome just by changing your diet. There's a special diet called FODMAP which supposedly helps with IBS and related diseases. I also think that a number of fad diets main benefit is influencing your gut bacteria.
> When the researchers investigated the microbiomes of [mice who avoid social contact], they found the animals lacked a common species called Lactobacillus reuteri. When they added a strain of that bacteria to the diet, the animals became social again.
Dr. Costa-Mattioli found evidence that L. reuteri releases compounds that send a signal to nerve endings in the intestines. The vagus nerve sends these signals from the gut to the brain, where they alter production of a hormone called oxytocin that promotes social bonds.
Other microbial species also send signals along the vagus nerve, it turns out. Still others communicate with the brain via the bloodstream.