Norah O’Donnell: Secrets of the gut microbiome and how it impacts our long-term brain health
I have always been interested in the idea of food as medicine, and the significant role our diets play in our long-term health. On the latest episode of “Healthful,” I sat down with Dr. Laura Cox, an assistant professor at Brigham and Women’s Hospital and Harvard Medical School.
Cox is an expert on the gut microbiome and what it means for our neurological health.
The gut microbiome “is the trillions of microbial cells that live in our guts,” she explained, describing it as “a community of microbes that supports our health” by making vitamins, educating our body’s immune system and even protecting us from pathogens.
The gut microbiome can affect our brains by changing our immune systems and our metabolism, Cox said.
Her work also focuses on whether gut health is linked to neurodegenerative diseases like Alzheimer’s and Parkinson’s.
Here are some of the takeaways from our conversation — watch it on YouTube and listen wherever you get your podcasts:
Can GLP1s help prevent Alzheimer’s disease?
According to Cox, researchers are learning more about the effects of GLP-1 drugs, which are used to treat diabetes or obesity, on our gut health.
“GLP-1s can affect the gut microbiome because they can act on the gut barrier and change some of the immune interactions,” Cox explained, adding that GLP-1 drugs can have a “direct effect on the brain.”
Researchers often refer to Alzheimer’s disease as “Type 3 diabetes” because of its link to insulin resistance.
“So the GLP-1 might have a direct protective effect in preventing Alzheimer’s disease,” Cox said. “Now in late stage, it doesn’t seem to have an effect. And it may be too late of an intervention there. But there may be a pathway for disease prevention very, very early on.”
The possible link between Parkinson’s, the gut and constipation
Gut inflammation is a “primary pathway” through which the gut microbiome can impact certain neurological diseases, such as Parkinson’s, Cox said.
“Parkinson’s disease is one of those diseases with the most evidence that the gut microbiome is involved,” Cox said.
Neurological diseases have “different signatures,” she said, and research has found that “constipation symptoms can precede” the onset of Parkinson’s by 20 years.
Cox said alpha-synuclein, the misfolded proteins that cause Parkinson’s disease, can sometimes start in the gut and spread up the vagus nerve — the nerve that carries signals between your brain, heart and digestive system.
According to Cox, studies have shown that cutting the vagus nerve, a surgical procedure known as a vagotomy, can reduce the risk of Parkinson’s.
Parkinson’s patients can also have a “gut inflammatory signature” that looks similar to that of inflammatory bowel disease because of an overabundance of proteins called lipocalin and calprotectin, Cox said.
“One of the things that we understand about Parkinson’s is that oftentimes, there’s a genetic risk plus an environmental risk on top of it,” Cox said. “We know that there are many pathways to Parkinson’s. So there are other environmental toxicants that can lead to this. We think the gut microbiome is a really important pathway there.”
Morning and night breast milk have different hormones
During pregnancy, according to Cox, a mother’s gut microbiome changes to look like her baby’s microbiome.
“She gets higher levels of what I like to call baby bacteria,” Cox said, which include the yogurt bacteria Lactobacillus and Bifidobacterium.
And during breastfeeding, studies indicate a mother can respond to the changing microbiome needs of her baby, Cox said.
“There are some studies that suggest that the mom can kind of respond to the baby, and if she senses inflammation, she can kind of send out different signals,” Cox said. “We know that breast milk contains many different components to feed an infant’s gut microbiome.”
Furthermore, new research shows the breast milk a mother produces in the morning is different in composition than the breast milk produced at the end of day, containing higher levels of hormones designed to either help their infants stay awake or sleep.
So mothers who pump breast milk can label the two different types.
“For example, there’s higher levels of melatonin, the sleep hormone, in the late-night milk,” Cox said. “So then there’s higher levels of cortisol, the awake hormone, in the a.m. milk. And so the thought is, if you separate that, you might be able to get your baby to sleep better.”
Vitamin B serves several important functions
Cox said vitamin B is crucial to our health because it plays several roles in the body.
“It tunes the immune system,” Cox said. “It supports brain health. And it’s been linked to many different neurologic diseases.”
Cox explained that researchers can study a sample of your gut microbiome and sequence it to determine what chemicals your microbiome is producing and if it’s potentially the source of a vitamin B deficiency.
“We’re trying to say not just how can I have a generic healthy microbiome, but what is your microbiome lacking?” Cox said. “What is it producing? And so how can we keep everything in balance that way?”
