The trillions of good and bad bacteria that inhabit your gastrointestinal tract are collectively known as the gut microbiome. Disruption – or dysbiosis – of this microbial community occurs when beneficial gut bacteria are depleted or overwhelmed by harmful inflammatory bacteria. Autoimmune diseases like rheumatoid arthritis, multiple sclerosis, and type I diabetes are linked to dysbiosis; so are neurological disorders, including pain, depression, anxiety, autism, and stroke.

Eating kefir and yoghurt help as they provide live bacteria, such as Lactobacillus and Bifidobacterium. Also helpful are prebiotics, the non-digestible carbohydrates that help probiotics survive. The probiotics in the gut ferment prebiotics to use as an energy source. Fermentation releases short chain fatty acids, calcium and magnesium from our food, and discourages pathogenic microorganisms from invading our system. Natural sources of prebiotics include fermented foods (kombucha, sauerkraut, kimchi), ground seeds, asparagus, and garlic, which is both antibiotic and prebiotic, fostering healthy microbes and eliminating unhealthy ones.

Research discoveries

It’s now broadly accepted that the gut is connected to the entire body – something naturopaths have known for centuries – so unsurprisingly, studies show probiotics can benefit many conditions, ranging from infectious forms of diarrhoea, irritable bowel syndrome, and inflammatory bowel disease, to eczema, allergies, colds, tooth decay, and periodontal disease. Some surprising recent discoveries about probiotics include their potential to help with depression, and lower LDL and total cholesterol levels. In a 2016 clinical trial published in Frontiers in Aging Neuroscience, scientists revealed that a daily dose of probiotic Lactobacillus and Bifidobacterium bacteria taken over two weeks yielded significant improvements in scores of Alzheimer's patients on the Mini-Mental State Examination (MMSE) scale, a standard measure of cognitive impairment. Chronic rheumatoid arthritis and inflammatory bowel disease are associated with behavioural symptoms including fatigue, depression, and social withdrawal; a University of Calgary study has found probiotic treatment reduces these behaviours, apparently by altering communication between the immune system and the brain.

But possibly the most exciting discovery of all relates to probiotics’ impact on the secondary effects of traumatic spinal cord injuries, such as loss of bowel control, which cause dysbiosis. Ohio State University researchers found that spinal cord injury alters the type of bacteria in the gut. Mice with the greatest changes in their gut bacteria tended to recover poorly from their injuries, and those animals pre-treated with antibiotics to disrupt their gut microbiomes before spinal cord injury showed higher levels of spinal inflammation and reduced functional recovery. However, when injured mice were given daily doses of probiotics, they showed less spinal damage and regained more hind-limb movement. While previous studies have shown a direct correlation between gut microbes and the central nervous system, this research highlights a previously unappreciated role for the gut-central nervous system-immune axis in regulating recovery after spinal cord injury.

Do you need a top-up?

It can be difficult to meet your probiotic needs from food alone, for example when taking antibiotics. Signs you may be short on probiotics include:
*digestive disturbances, e.g. bloating, gas, constipation, diarrhoea or cramping after meals
*unusual cravings for sugar and other unhealthy food
*erratic sleep patterns
*mood disorders
*skin conditions
*poor immunity
*yeast infections
It's important thing to seek professional advice about supplementation, because probiotic strains must be rotated for maximum effectiveness.

Teresa Mitchell-Paterson BHSc(CompMed) MHSc(HumNut) AdvDipNat is a member of the Australian Traditional Medicine Society.