A healthy gut is essential for a healthy brain. In recent years it has become establish that there are many ways in which the gut communicates with the brain, and vice versa. This includes the production in the gut of neurotransmitters including serotonin, dopamine, noradrenaline and GABA which directly influence the brain; the gut’s ability to absorb critical brain-friendly nutrients such as vitamin B12; its role in controlling inflammation and eliminating potential brain-damaging toxins; and role of the gut microbiome – the balance of trillions of bacteria that populate our gut.
Two gut-related predictors or Alzheimer’s – periodontal disease and lack of stomach secretions required for vitamin B12 absorption – illustrate this microbiome -gut-brain connection.
Having periodontal (gum) disease, a consequence of infection and dysbiosis, is associated with a significant increase of cognitive decline, with increasing dental visits correlating with Alzheimer’s.
Decreasing production of stomach acid, required for vitamin B12 absorption, is a common occurrence in those over age 50. Two in five over 61 have low blood levels of B12. Gastritis, irritable bowel syndrome (IBS),gut infections such as H.pylori, long term use of PPI antacids and antibiotics have all been implicated or associated or with increased risk of cognitive decline and dementia.
The intestinal gut barrier functions much like the blood brain barrier, ideally allowing nutrients to pass while rejecting toxins and ant-nutrients. The integrity of the gut barrier is affected by alcohol, gliadin in wheat, a lack of antioxidants and anti-inflammatory omega-3 fats which influence the microbiota. Gut inflammation may play a role in cognitive decline.
The role of the microbiome in the gut affecting cognition is a new frontier for research. A study giving aged rats a fecal transplant from young rats showed significant changes in cognition illustrates the potential role for probiotics, prebiotics and diets that promote a healthy microbiome. While there is little clinical trial evidence yet there is a growing body of evidence that restoring gut health and eating a diet which supports gut health, is correlated with and likely to be beneficial for protecting cognition.