Parkinson’s disease, autism, and depression – could diet be the cause of these and other supposed diseases of the brain?
An increasingly compelling body of scientific research suggests it is.
Numerous studies into the branch of the nervous system that lies in the gut – the enteric nervous system (ENS) – indicate that, contrary to popular belief, mood and behavior disorders don’t necessarily originate in the brain. While the ENS regularly communicates with the brain to regulate things like appetite, alteration of the gut environment can distort this communication and result in mood and behavior disorders.
This may explain the puzzling gut symptoms known to occur in patients with neurological diseases and vice versa. For example, patients with Parkinson’s disease often report constipation and bowel-related symptoms up to 10 years before the familiar motor deterioration symptoms of Parkinson’s disease begin.
So, how does it work? Is it what, when or how much you eat that causes the type of gut dysfunction that triggers brain-related conditions? To find the answer, we have to look deep inside the intestine and explore something known as the gut microbiota.
Influence of the gut microbiota on health
The gut microbiota is the collective term for the 100 trillion plus microorganisms that live in the bowels. These organisms include fungi and bacteria and are involved in maintaining normal metabolism, absorption of nutrients and immune function. Disruption of the delicately balanced gut microbiota – either through excess or lack of important microorganisms – is known to result in gastrointestinal conditions, such as inflammatory bowel disease. Disruption of the delicately balanced gut microbiota – either through excess or lack of important microorganisms – is known to result in gastrointestinal conditions, such as inflammatory bowel disease.
But that’s not all. It now appears that upsetting the gut microbiota has repercussions far beyond the bowels.
Scientists have long known that the intestinal microbiota and the substances it produces (known as metabolites) directly affect the gut’s ability to function properly. A loss or excess growth of bowel bacteria and fungi can affect intestinal permeability, how easily nutrients are absorbed into the body and normal bowel movements. This is why bowel conditions like IBS often develop after food poisoning or other gut infections that upset the balance of normal gut bacteria, fungi or viruses.
How the gut communicates with the brain?
You may be familiar with the hormone serotonin. It’s a neurotransmitter that your brain releases after activities such as eating chocolate or laughing. That’s why doing these things feels so good. But did you know that scientists now believe 95% of serotonin is made in the gut, not the brain?
It’s not just the production of neurotransmitters within the gut that links the intestinal microbiota and the brain; there’s also the role of immune cells. Your gut has an extensive immune system that protects your body against infection, inflammation, and damage. When foreign organisms invade the body, the cells of the immune system (both in the gut and elsewhere) release substances to start the fight against the infection.
How antibiotics can upset the gut balance?
The gut does a great job of balancing its levels of the bacteria and fungi that keep it working as it should, but this fine balance can be easily upset by eating and drinking things that kill off gut microorganisms. And that includes medicines, specifically antibiotics. Take these drugs too often or for long periods of time and they can kill off the strains of bacteria the gut needs to function at its best. If you want to maintain a healthy gut, step number one is to avoid unnecessary antibiotic use.
When you do require antibiotics for a bacterial infection, you can prevent them from wiping out your protective gut bacteria by topping up your levels of ‘good’ bacteria with a probiotic supplement or natural foods like ‘live’ yogurt, kefir and pickled vegetables.
What constitutes a gut-friendly diet?
Eating a gut-friendly diet is another way to maintain a healthy gut microbiota. This starts with minimizing your intake of the sugary foods, refined/processed carbohydrates that encourage the growth of ‘bad’ gut microorganisms, like Candida albicans.
So cut out the processed carbs and sugar if you want to maintain optimal gut health (and get your carbs from healthier sources such as vegetables, fruits, nuts, and seeds). And watch your alcohol intake too. The science is clear: what you eat really can impact on your overall health, mood, and mental wellbeing by altering the way your gut’s microorganisms ‘talk’ to your brain. The good news is that you can take control of your gut health today without any need for medication or a complicated treatment plan. And don’t forget to prioritize getting a good night’s sleep.