Research suggests the health of the gut biome as a conduit to optimal brain health.
I'm a neurologist, a sports neurologist, but certainly not a gastroenterologist, so it may seem strange, on the surface, that I'd write an article about gut health. However, there is increasing clinical evidence to suggest (if not yet prove) that our intestinal health may have a significant influence on our brain health and vice versa. The gut-brain connection makes sense when breaking it down as it involves the neural "communication highway." And as a neurologist, I have expertise here. After all, the field of neurology involves the study, diagnosis, and treatment of disorders that affect the nervous system – a portion of which is found in the gut.
A significant derivative of the autonomic nervous system, the enteric nervous system is a meshy layer of neurons that rule over the function of the gastrointestinal tract or the "gut." This stomach lining of neurons has, for quite a while, been nicknamed the "second brain." The enteric nervous system gives us the feeling of "butterflies" in our stomach when we're anxious or joyful and is credited with providing that "gut feeling" when we are highly convicted about something. But beyond these emotional reactions attributed to the gut, research is continuing to explore the ways our enteric nervous system is involved in determining our mental state (for better or worse), as well as the roles it may play in neurological disease.
Researchers at private research university Caltech in Pasadena, California, were recently provided an $11 million grant to study the gut-brain connection related to Parkinson's disease. As more studies are uncovering abdominal abnormalities in the guts of people diagnosed with this progressive nervous system disease, a deeper understanding of how those abnormalities may play a role in the development or trajectory of Parkinson's Disease is crucial. Studies are also diving into the role of the gut-brain connection in people with dementia and other neurologic disorders. A 2019 Alzheimer's & Dementia study linked cognitive impairment in older adults to lower than optimal concentrations of primary bile acid in the gut than those with normal cognition.
In addition to the potential gut-brain connection involved in degenerative neurological conditions such as dementia and Parkinson's Disease, much research is being conducted on the overall inflammatory immune response in the gut to the Standard American Diet (SAD) and its role in reducing optimal brain health. The human gut biome was not designed for the way we eat today, and if we aren't fueling our bodies with the nutrition they were designed to function well on, inflammation can result and impact the brain. So which comes first: a healthy brain or a healthy gut? Certainly, correlational or exploratory studies do not yet equal causation, and more research is needed.
The good news is – plenty of studies have demonstrated that good sleep hygiene and regular exercise benefit both the brain and the gut. Probiotic supplements designed to enhance "good" bacteria in the gut may also help, but they really can't "overhaul" an otherwise poor diet.
Research suggests that parts of the world with primarily plant-based diets tend to present less evidence of neurologic disease and disorder than those with a diet abundant in highly processed, low-fiber, lower nutritional value foods. If eliminating fatty, sugary, or otherwise highly processed foods isn't something you think you can do successfully, aim for moderation instead. Consider starting with a healthy swap for one meal a day – and try it consistently over time. Once you've achieved some consistent success with that goal, try replacing sugary or artificially sweetened beverages for water or no-sugar alternatives, and so on.
An extremely unhealthy diet was not built in a day, so weening off such highly addictive foods can be a challenge. Give yourself time to make substantial and lasting changes in this regard by easing into the effort. For those who like eating "plans" or a place to start – the Mediterranean diet is anti-inflammatory, good for the brain, and associated with longer life expectancy. Again, when adopting dietary changes such as those included in a primarily Mediterranean diet, for lasting success, go for small swaps over time versus a sweeping overhaul. Instead of using vegetable oil when cooking, opt for olive oil. Instead of white bread, consider whole grain. Toss a chicken patty on the grill at the next cookout instead of a beef burger.
I am pleased to see so many connections being made recently to the optimal health of our brains as influenced by the health of other body systems. Even better news in this regard is that each of us possesses an element of control. Knowing we can choose what we put into our mouths as fuel for the body and brain gives us power. So, claim that power and choose wisely. Your belly and your brain will thank you for it.
Sources:
https://www.brainandlife.org/articles/exploring-link-between-gut-brain-health/
https://www.mindbodygreen.com/articles/gut-health-mental-health-connection-from-neuroscientist
https://pubmed.ncbi.nlm.nih.gov/24997029/
https://www.scientificamerican.com/article/gut-second-brain/