This Is Exactly How Anxiety Can Harm Your Gut Microbiome, From A Therapist

Have you noticed that symptoms like stomachache, headache, gassy belly, or muscle pain might co-occur on days when you feel more frazzled? Like when you wake up with a mild headache, physical discomfort can set you up for a day of impatience, irritability, and overall frazzle-brain. It can feel and sound as if your body were a discordant instrument of noisy discomfort.

The link between gut and mental health

Here's a little gross-ology for you. We are composed mostly of single-celled organisms. Our own cells are outnumbered 10 to one by these organisms, primarily bacteria residing in our gut. Called the microbiome, our gut bacteria transmit from the placenta and amniotic fluid2 in our mother's womb. If your mother experienced severe stress during pregnancy, you might show a decrease of Bifidobacterium associated with proneness to inflammation.

Research with adult subjects showed that those with a rich diversity of gut bacteria had better immune system health. Those with a less diverse microbiome were prone to pro-inflammatory bacteria. Inflammation in the gut can put you at risk for irritable bowel disease3 and other disorders4. "The road to health is paved with good intestines," Sherry A. Rogers quipped. That road to good health begins at birth.

Babies born vaginally and breastfed babies showed a richer diversity of gut bacteria5. Hope is not lost if you or your children missed out on these early natural benefits. The microbiome differences between babies born by C-section or vaginal delivery tend to even out over time6 as babies adapt to a solid food diet. Good early nutrition from birth to age 3 helps babies develop a healthier microbiome.

It is heartening to note that your microbiome adapts to your environment and diet throughout your whole lifespan. Changes in gut bacteria can occur in as little as 24 hours2 after a change in diet. When you foster a more diverse bacterial climate, you obtain many health benefits2, including:

You can reduce stress with well-balanced nutrition7 that includes a variety of fruits and vegetables every day. Good nutrition not only helps your physical health, but it benefits your mental health as well.

How gut bacteria can support mental health — and vice versa

Gut bacteria manufacture about 95% of the body's supply of serotonin. Serotonin is a neurotransmitter or chemical messenger released by a nerve cell. Serotonin is essential in the treatment of depression and anxiety. It also plays a role in the normal operations of most of our brain functions, including regulation of mood, appetite, sexual functioning, memory, and sleep. Deficits of serotonin lead to increased irritability, anxiety, depression, and anger.

In some promising studies with mice, researchers found that anxious mice given water laced with probiotics (helpful bacteria) were less likely to give up during a physical challenge and produced less stress hormone, corticosterone (showing a reduction of symptoms of depression and anxiety). A study with human subjects8 showed a significant decrease in anxiety and depression after only a 30-day course of probiotics.

A growing body of research demonstrates that a healthy mix of bacteria in the gut can improve our physical and mental health. To better understand how this works, let us start with a basic understanding of digestion.

Digestion begins in the mouth. As you chew that crispy McIntosh apple, saliva starts to break down the nutrients. The action of chewing sends a message to your stomach to release digestive enzymes to break down the nutrients further. Muscles and mucosa continue breaking down the foods we eat as they move through our digestive tract (mouth, esophagus, stomach, small and large intestine, rectum, and anus).

When we race through the day, multitasking while shoving food into our mouths, we add stress to the work of digestion. Stress can cause the esophagus to spasm. It can also cause indigestion. Indigestion increases the environment for the growth of unhealthy bacteria in the gut. Harmful bacteria trigger a discordant cascade of unpleasant symptoms.

Over time, chronic, unmanaged stress can lead to inflammatory responses and disease. You can decrease and even eliminate these toxic effects with a daily stress management practice, like the practices offered in this book. When you learn to generate a feeling of internal peace and harmony, your body responds and soothes itself.

A New Yorker cartoon shows a couple at a table. One is reading a science magazine. The caption reads, "It turns out it wasn't the giant asteroid that killed the dinosaurs. It was stress about the giant asteroid that killed the dinosaurs."

While we cannot control all the asteroid disasters in life, we can manage our reactions to those stressors. Your body is built to withstand periodic stressful events without suffering long-term damage. The natural calming mechanisms of the body reset the nervous system once the stressor has passed. Practicing intentional behaviors that activate those natural calming mechanisms will strengthen your resilience.

You can think of the relationship between the brain and the gut as a conversation or a musical duet. Like a musical duet, sometimes one person sings, then the other, and then they sing together. Managing stress effectively requires harmonizing the musical conversation between your brain and your gut:

Top-Down (Brain to gut): Your thoughts and actions can decrease stress by activating positive coping strategies that lower the discharge of cortisol and other messengers that cause the stress response.

Bottom-up (Gut to brain): Gut bacteria, inflammation, and other physiological responses affect brain chemistry, mood, and stress responses. Strengthening the diversity of the gut biome improves overall health and well-being.

It is best to use both top-down and bottom-up remedies to reduce anxiety and stress and improve physical and mental health.