We should have listened to our guts all along. Our brains are considered the most complex organs in the human body. The brain is the central control system of the body, controlling everything from involuntary and voluntary behavior to nervous system functioning, including our cognitive functioning and health. Now, a strong correlation has been found between brain activity, brain health, and gut bacteria. Will it change how we perceive development and behavior?
One of the most complex structures in the universe
Planet Earth has undergone significant, uninterrupted evolution for billions of years, gradually transitioning to the life-sustaining world we all know today. However, evolution is not limited to Earth, but also extends to all the living organisms it hosts, including humans. The first human species had significantly different behaviors from those of modern humans today.
Behind the evolution of human behavior lies the evolution of the human brain, which was significantly smaller until 2 million years ago, when it evolved into a larger size to enable the use of tools and create fire. As the climate and the world changed, our brains changed as an adaptive response, ensuring we developed behaviors to help us adapt and survive.
However, recent studies indicate that environmental changes are not the only factor driving changes in brain development and activity. Internal changes specifically linked to our gut have been identified to play a key role.
Our gut’s role in brain activity and development
Our time to evolve may not have to come to an end just yet, as the world continues to adapt to and battle climate change to survive. However, while several technologies have been invented to mitigate the effects of climate change, it has already impacted human health. Our brain health, in particular, is affected by air pollution and extreme heat, which could lead to:
- Cognitive impairment
- Neurodevelopmental risks
- Neurological disorders
- Physical brain changes (myelin plasticity changes)
A 2022 study published in Clinical and Experimental Pediatrics discovered a key relationship between a human’s gut bacteria and brain development and activity. Controlling gut bacteria in a host affects the host and its brain’s development and activity, as gut bacteria communicate with the brain through various neuronal activity and neurotransmitter signals.
This study, along with a study by Northwestern University researchers, also indicates that gut bacteria may play a key role in neurological disorders, increasing insight into mental health.
Clinical importance of the gut and brain relationship
The 2026 Northwestern University study, led by Katie Almato, an associate professor of biological anthropology, analyzed the effects of varying gut bacteria on mice’s brain activity. The study results were interesting, potentially affecting cases of compassion towards ourselves. Gut bacteria from humans, squirrel monkeys, and macaques were introduced to mice lacking gut bacteria.
Results
- Human and squirrel monkey gut bacteria resulted in:
- Increased energy production
- Higher learning and adapting brain activity (synaptic plasticity)
- Macaques’ gut bacteria resulted in:
- Increased patterns associated with autism, ADHD, schizophrenia, and bipolar disorder
“Based on our findings, we can speculate that if the human brain is exposed to the actions of the ‘wrong’ microbes, its development will change, and we will see symptoms of these disorders, i.e., if you don’t get exposed to the ‘right’ human microbes in early life, your brain will work differently, and this may lead to symptoms of these conditions.” – Amato
Amato believes these insights reshape our understanding of how neurological disorders originate. While environmental factors play a role in brain behavior and activity, we should also learn to listen to our guts, as it also impacts our revolutionary outlook. Managing factors that alter our gut bacteria, such as heat and cold stress, is thus essential to our health. This is why more companies are urged to invest in heat-stress combating.
