Secrets of the gut microbiome and how it impacts our long-term brain health

Dr. Laura Cox, an assistant professor at Brigham and Women's Hospital and Harvard Medical School, discusses the gut microbiome and its impact on long-term brain health for the latest episode of Healthful. The gut microbiome is a community of trillions of microbial cells that support our health by producing vitamins, educating the immune system and protecting against pathogens.

Cox explains that the gut microbiome can influence the brain by altering our immune system and metabolism. Her research also investigates whether gut health is linked to neurodegenerative diseases like Alzheimer's and Parkinson's. GLP-1 drugs, used to treat diabetes or obesity, can affect the gut microbiome by acting on the gut barrier and changing immune interactions. These drugs may also have a direct protective effect against Alzheimer's disease.

Parkinson's disease has a strong connection to the gut microbiome, with gut inflammation being a primary pathway through which the microbiome impacts neurological diseases. Alpha-synuclein, the misfolded protein responsible for Parkinson's, may start in the gut and spread to the brain via the vagus nerve. Vagus nerve removal, or a vagotomy, can reduce the risk of Parkinson's, while patients often exhibit a gut inflammatory signature similar to inflammatory bowel disease due to an abundance of lipocalin and calprotectin proteins.

Breastfeeding mothers' gut microbiome changes to resemble their baby's microbiome, with higher levels of "baby bacteria" such as Lactobacillus and Bifidobacterium during breastfeeding. Breast milk composition varies throughout the day, containing different hormones to either help infants stay awake or sleep. Pumped breast milk can be labeled as morning or night milk, with higher melatonin levels in late-night milk and higher cortisol levels in morning milk.

This suggests that separating the two types of breast milk may help babies sleep better. Vitamin B plays several crucial roles in the body, including tuning the immune system and supporting brain health. Researchers can analyze a sample of a person's gut microbiome to determine if it's producing the necessary vitamin B chemicals or lacking them, aiming to maintain a balanced microbiome.