Gut-Brain Axis and Mental Health

Anxiety and depression have become widespread in America, with approximately one-third of the population reporting an anxiety disorder, and over 20% of adults experiencing a major depressive episode at some point in their lives. Alongside these mental health challenges, chronic fatigue and brain fog are becoming increasingly common, both of which are associated with neuroinflammation—an inflammatory response in the brain. A growing body of research has revealed that our diet and gut health play a critical role in mental health through the “gut-brain axis,” as well as through the gut’s ability to protect the body from systemic inflammation that can affect the brain. A healthy gut lining and diverse microbiome act as a robust defense, preventing external factors from overwhelming our bodies and contributing to mental health issues.
The connection between gut health and mental well-being is so profound that studies in animals have shown that simply transferring the microbiome of depressed animals to healthy ones can quickly induce depression-like behaviors.
In my own life, I’ve experienced this gut-mood link firsthand. In my early career, during my stressful, sleep-deprived years as a surgical nurse in a specialized hospital in Middle East, I developed severe gastrointestinal issues. My diet, primarily made up of hospital food, and the constant stressful 12-hour shift and it took a toll on my gut health. Within months, I developed pains in my stomach followed by constipations. At the same time, I was struggling with debilitating anxiety and stress, caused by long hours of intense work and poor eating habits, often not fueling my body with the right foods at the right times. It became clear to me that gastrointestinal issues, along with other health problems like immune system imbalances and thyroid disorders, are often closely linked.
When I moved to the U.S., the stress only increased, and I didn’t realize how different the food here was compared to what I had been used to in the Middle East—healthier, more natural options were harder to come by. Over the next few years, I visited multiple doctors to address my ongoing mood disorders and sudden acne breakouts in my  mid 30s, even though my blood work showed no issues with my thyroid or hormones, and an endoscopy didn’t reveal any abnormalities in my stomach.
It’s clear that many aspects of our modern lifestyle, characterized by stress, sedentary behavior, and a convenience-driven culture, are contributing to the current mental health crisis. Several factors that damage our gastrointestinal function include:

Ultra-Processed Foods (UPFs): These industrially engineered “Frankenfoods” dominate modern diets and often contain artificial additives, preservatives, synthetic flavors, emulsifiers, and pesticide residues—all of which can disrupt the gut microbiome and harm the gut lining.
Excessive Sugar: A high intake of sugar, particularly fructose, promotes the growth of harmful bacteria and yeast in the gut, which can lead to inflammation and weakened gut integrity.
Chronic Stress: Psychological stress can disrupt the gut microbiota and increase intestinal permeability by influencing the gut-brain axis. Chronic stress can stem from various sources: social media, unresolved childhood trauma, work pressures, relationships, negative self-talk, caregiving, and more. Overuse of Antibiotics: Antibiotics can wipe out beneficial gut bacteria, leading to imbalances that weaken the gut barrier and trigger inflammation.
Excessive NSAID and Anti-Reflux Drug Use: Medications like ibuprofen and Aleve, commonly used for pain relief, can cause intestinal inflammation and increase gut permeability. These drugs are often overused and have a significant impact on gut health. Low Fiber and Low Polyphenol Diets: A lack of fiber and polyphenols (found in colorful fruits, vegetables, nuts, and spices) can reduce the production of beneficial short-chain fatty acids (SCFAs) that are crucial for gut health and metabolic function.
Gluten: Gluten can trigger the release of zonulin, a protein that increases intestinal permeability, leading to what’s often referred to as “leaky gut.”
Alcohol: Regular alcohol consumption can inflame the gut lining and disrupt the tight junctions between intestinal cells, contributing to increased permeability.
Poor Sleep: Insufficient or poor-quality sleep disrupts the gut microbiome and increases gut permeability by triggering stress hormones and misaligning circadian rhythms. It is important to be in bed by 9:30 as the needed potassium to regulate Leptin(fat burner hormone) start to absorb from air from 9:30PM to 2:00 AM.
Lack of Exercise: Physical inactivity can negatively alter gut microbiota composition, while regular exercise has protective effects on gut health.
Chronic Inflammation: Low-grade, persistent inflammation—often driven by obesity, metabolic syndrome, environmental toxins, and stress—can damage the gut lining over time.
Artificial Sweeteners: Some artificial sweeteners, like aspartame and sucralose, can disrupt the gut microbiota and compromise the gut barrier.
Environmental Toxins: Exposure to pollutants, heavy metals, and pesticides can damage the gut lining and negatively affect the microbiome, leading to increased intestinal permeability. If you are not having enough reserve energy (this is building up by having perfect cell barriers) the toxins get into your cells while if you have perfect cell barriers(this is get done by calcium) these toxins wont harm your body.
Vitamin D Deficiency: Vitamin D is essential for maintaining gut barrier integrity, and many Americans are deficient. Optimal levels should range from 40-60 ng/mL. I emphasis to get your D from sun light unless you are extremely acidic, so you can take supplements.
Infections: Bacterial and viral infections, including COVID-19, can alter the gut microbiome and compromise gut function.
Not Enough Sunlight: Research has shown that people with insufficient sunlight exposure have less favorable microbiome profiles. The average American now spends over 90% of their time indoors or in a car.

All of these factors contribute to gut dysbiosis and increased intestinal permeability, which in turn can have a profound impact on mental health. Understanding the role of gut health in mental well-being is an essential step in addressing the root causes of anxiety, depression, and other modern ailments.
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