There is growing evidence that by improving gut health, we can improve mental health and brain health too!!
Clinical trials altering gut microbes, alter mental health and brain health outcomes
Gut healthy diets and brain healthy diets are virtually identical, so a common link makes sense
These diets are: - high in plant foods (veges, legumes, fruit, whole grains -moderate in fat (mostly olive oil, nuts, seeds), and omega 3 - low in red meat, ultra processed foods, refined carbohydrates, added sugar and alcohol
They also contain fermented foods
So here's the science....
The brain and the body are separated by tightly joined cells called the blood brain barrier These filter what gets to the brain, and only allow very small/fat soluble molecules, and some gases through as well as specific larger molecules (such as glucose) via transporter proteins
The blood brain barrier is vital to protect the brain from germs and toxins, while allowing nutrients to pass through
This also means that many medications and chemicals cannot pass through, such as serotonin from the gut (happy hormone)
The gut and brain are directly connected by the vagus nerve however, which constantly sends signals back and forth
This is part of how stress can cause gut issues, and how stress reduction techniques can improve gut health and symptoms (think of how your gut feels when you are nervous!)
We don't REALLY know exactly how the gut brain connection works right now, but the theories are as follows :
gut cells produce most of serotonin in the body, this may affect brain signalling (serotonin from the gut cannot pass directly into the brain though)
the majority of the bodies immune cells also reside in the gut, and produce cytokines (chemical signals), which influence neural pathways, and brain inflammation
good' gut bacteria produce compounds such as butyrate (short chain fatty acids) which can alter the blood brain barrier activity (similar to leaky gut)
some gut microbes also produce neurotransmitters ie dopamine, serotonin, GABA
So if you are trying to improve mental health or brain health, don't forget to think about your gut health too!