Stress is an evolutionary adaptation that provides a quick response for flight or fight in the face of danger. In the short term, stress responses are beneficial because they aid survival, but prolonged exposure to stress or chronic stress is detrimental to health, whether physiologically, emotionally, or behaviorally.

The perception of stress occurs not only in response to environmental dangers but is also related to other factors, including diet type, microbiota diversity, social interactions, etc.

The gastrointestinal system possesses an enteric nervous system made up of more than 100 million nerve cells that line the gastrointestinal tract from the esophagus to the rectum, communicating with the brain and vice versa. It constitutes a circuit of neurons, hormones, and neurotransmitters that sends messages to the brain informing it of the state of the gut, and the brain can send signals that in turn impact the intestinal environment, modifying the microbiota.

The composition of the microbiota directly influences serotonin levels, the neurotransmitter responsible for the feeling of happiness and tranquility. It has been shown that a varied diet and respecting our chronobiology contribute to a diverse and healthy microbiota.

Inadequate quality of the microbiota can alter our perception of the world and produce social behavior deficits, which manifest, for example, in neuropsychiatric conditions such as ASD, social anxiety, depression, or in problems such as the need to eat unhealthy and addictive foods.

Foods rich in prebiotic vegetable fibers are non-digestible dietary components metabolized by the gut microbiota that promote the growth of beneficial bacteria, including the genera Bifidobacterium and Lactobacillus. Diets rich in omega-3 or the intake of supplements have modulated altered behaviors.

Studies on children with ASD showed improvement in microbial composition when chia seeds were added to their diet, which suggests that alterations in the microbiota of autistic individuals may be due simply to the absence of sufficient nutrient intake and the negative effect of some medications that negatively alter the composition.

Modulation of the microbiota through the administration of specific probiotics (Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Lactobacillus acidophilus, and Lactobacillus rhamnosus, among others) has been considered beneficial for the regulation of the microbiota, reducing social deficits.

Bibliography:

Eoin Sherwin, Seth R. Bordenstein, John L. Quinn, Timothy G. Dinan, John F. Cryan*. Microbiota and the social brain, Science 01 November 2019, Vol. 366, Ed. 6465

https://science.sciencemag.org/content/366/6465/eaar2016.full