A Gut Feeling: How Gut Health Impacts Mental Health

The Health series is presented by AdventHealth

We all know what it feels like to have a “gut feeling” about something. While that saying is mostly figurative, there is a bit of truth to it. Our guts house most of the microbes in our body that have a profound impact on not only our digestive and immune health but our mental health too.

“Our health is completely dependent on a healthy microbiome,” says Tereza Hubkova, MD, an integrative medicine physician with AdventHealth’s Whole Health Institute. “Microbiome refers to all the microscopic organisms (bacteria, viruses, fungi, and archaea) that live in us and on us with their genes—which, combined, have millions of genes, vastly more than in our own human genome.”

For much of our recent history, microbes were viewed mostly negatively as the cause of many diseases. However, we have come to understand that most microorganisms are highly beneficial and even crucial to our health and the health of the planet. 

“Microbes have been here on Earth much longer than we have,” Hubkova says. “We have developed a mutually beneficial relationship. They help us absorb nutrients, manufacture important signaling molecules, vitamins, and neurotransmitters, protect us from disease-causing invaders, and are absolutely crucial for a healthy immune system, nervous system (including brain development), as well as metabolism.”

Everyone’s microbiome is shaped by the way they are born, whether they were breast-fed, their lifestyle, the medications they are exposed to, stress level, and more. The biggest leverage we have over our microbiome is based on what we choose to eat.

You Are What You Eat
“If you eat junk food, you’re going to have a ‘junk microbiome,’ which can’t keep you healthy,” Hubkova notes. “Fast food is associated with depression, while a diet rich in fiber and color from a variety of plants has been linked to better brain health. Fast food is full of sugar, fat, and salt, but lacks micronutrients and fiber. It is a double whammy: it feeds the ‘bad’ microbes but starves the good ones. The result is dysbiosis, or a lack of diversity and lack of resilience.”  

The result? Inflammation and leaky gut, resulting in trafficking of bacterial components like endotoxin into the blood and brain—a recipe for disaster. Inflammation and endotoxin in the brain have been linked to mood disorders such as depression and anxiety, the alarming rates of autism, and neurodegenerative disorders like Parkinson’s disease and Alzheimer’s. The devastating effect of poor diet on our microbiome is worsened by antibiotics and pesticide residues in our food.

“Just one course of antibiotics has been associated with a 23 to 25 percent higher risk of developing depression and a 17 percent higher risk of anxiety,” Hubkova says. “Antibiotics can save your life when prescribed appropriately, but sadly, the majority of antibiotics are dished out for the wrong reasons (viral infections). It really comes down to working with your primary care physician and trying to understand when antibiotics are the right choice.”

Tereza Hubkova, Integrative Medicine Physician

Protecting Those Healthy Microbes
Everyone’s microbiome is shaped significantly during gestation and the first three years of life. The healthier a mother’s microbiome is while carrying and delivering her baby, the healthier the baby’s microbiome will be. The child’s microbiome is then influenced by factors like Cesarean section versus vaginal birth, breast-feeding, and environmental factors in those early years of life.

“When little children experience stress or are exposed to antibiotics, it’s so much more harmful than if it happens during adulthood because their microbiome is still developing,” Hubkova says. “Harming the microbiome in the early life can have profound consequences on the immune system and metabolism and also contributes to the epidemic of mental health disease.”   

Prolonged use of antibiotics in midlife has been linked to cognitive decline.
Is there anything we can do to protect our microbiome? In a small study of babies given probiotics versus placebo for the first six months of life, 17 percent of those on placebo developed either autism or attention deficit disorder by age 13, compared to none of the babies given probiotics. 

“I don’t think it was coincidence, but I hope to see more trials like this,” says Hubkova. “Adult volunteers in another study that were given probiotics reported better mood and less distress and had lower stress hormone levels compared to a placebo group. Other studies show improved memory with probiotics, as well as beneficial effect of fiber on memory, multitasking, and maintaining focus.”

Hubkova says she doesn’t think we can reverse all the damage done to our microbiomes just by popping probiotics. “But they do seem to have a role, along with a well-balanced diet rich in fiber, exercise, spending time in nature (including responsible exposure to sunshine), having healthy relationships, and a positive attitude. All of this helps keep our ‘little friends’ in good shape,” she says. “The most important thing is realizing where we are making mistakes, as individuals as well as a society, and correcting them before non-reparable damage is done. The clock is ticking.”