Depression Isn't Just a Serotonin Problem. Here's What Else Matters
ESTIMATED READ TIME: 4-5 MINSFor years, we’ve been told that depression is mostly a "chemical imbalance" caused by low serotonin.
It's true that serotonin can be involved in determining your mood, motivation, sleep, and emotional well-being. However, research suggests the causes of depression are much more complex than abnormal levels of a single neurotransmitter.
After years of working with people struggling with chronic illness—and after walking through my own health challenges—I've come to believe that our emotional health is deeply connected to the health of our entire bodies as well as our lifestyle choices and habits.
I've seen people experience improvements in their mood and overall mental health after restoring their gut health, balancing blood sugar, reducing chronic stress, correcting nutrient deficiencies, sleeping better, spending time outdoors, and reconnecting with God and community.
That doesn't mean someone should stop taking prescribed medications or end professional therapy. Rather, it means we should look at the whole person when attempting to lift their spirits, along with their behaviors and daily patterns.
For anyone dealing with depression, here are three root causes I encourage them to investigate first, alongside appropriate medical care.
1. Poor Gut Health
There's a reason the gut is often called the "second brain." About 90–95% of the body's serotonin is produced in the gastrointestinal tract, although that serotonin primarily regulates digestion and doesn't directly cross into the brain.
More importantly, the gut and brain are constantly communicating through the gut-brain axis—a two-way communication network linking your central nervous system, enteric nervous system, and gut microbiome.
When your microbiome becomes imbalanced, harmful bacteria can flourish while beneficial microbes decline, and this can trigger inflammation and other issues that impact your brain and therefore the way you think.
Researchers have found differences in the gut microbiomes of people with depression compared with healthy adults, including lower gut bacterial diversity, higher levels of harmful inflammation-causing microbes, and fewer bacteria that produce mood-regulating chemicals like butyrate and dopamine.
Several studies also suggest probiotics and fermented foods can often modestly improve depressive symptoms in some, especially when combined with standard treatments.
I believe this is one reason why healing the gut often becomes an important first step. Supportive habits to strengthen your gut-brain connection can include:
Eating fermented foods like sauerkraut, kimchi, kefir, or yogurt to introduce beneficial bacteria.
Drinking bone broth to provide collagen, gelatin, and amino acids that help nourish and support the intestinal lining.
Consuming fiber-rich fruits and vegetables that promote the production of compounds that support both gut and brain health.
Reducing ultra-processed foods, excess sugar, and artificial additives.
Including a quality probiotic supplement in your routine.
2. Chronic Stress and Elevated Cortisol
Our bodies were never designed to stay in survival mode. Stress that becomes chronic and lasts for many months or years causes cortisol to remain elevated.
Initially, cortisol helps us respond to challenges. Eventually, however, chronically elevated cortisol can contribute to depression symptoms such as:
Fatigue
Poor sleep
Anxiety
Low motivation
Inflammation
Impaired memory
Long-term stress also affects other hormones, including DHEA, testosterone, and estrogen levels, all of which influence mood, resilience, and energy.
Research consistently finds that many people with depression show dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, the body's primary stress-response system.
Among those with depression, I believe emotional and spiritual healing are just as important as nutritional healing.
Prayer, gratitude, time outdoors, healthy relationships, rest, and forgiveness help calm your nervous system, allowing you to get more restorative sleep and assisting in hormonal balance.
3. Blood Sugar Dysregulation
One connection to depression that doesn't receive enough attention is blood sugar. Every time blood sugar spikes dramatically and then crashes, stress hormones rise to restore balance.
Repeated insulin spikes can contribute to insulin resistance, which studies have found is associated with a higher risk of depression, independent of someone's body weight.
Additionally, poor blood sugar management and metabolic issues can contribute to chronic inflammation, reduced energy production, high cortisol, and disrupted supply of glucose, which the brain needs to regulate mood and cognitive function.
Many people notice steadier moods simply by stabilizing their blood sugar throughout the day, which can be done by prioritizing:
Protein at every meal (at least 25+ grams)
Healthy fats
Fiber-rich foods
Regular movement
Resistance training
Minimizing sugary drinks and refined carbohydrates.
The Bottom Line: Looking Beyond Brain Chemistry
Depression isn't a sign of weakness, nor is it always explained by a single neurotransmitter. Often it's a sign that something deeper needs your attention.
You might choose to start by:
Restoring gut health
Reducing chronic stress
Balancing blood sugar
Correcting nutrient deficiencies
Improving sleep
Spending time in the sunshine
Strengthening your relationship with God and your community.
If you're struggling with depression, please don't suffer alone. Depression is a real medical condition, and seeking help from a qualified healthcare professional, mentor, or coach is a sign of wisdom, not weakness—especially when combined with other lifestyle changes.
References:
https://pmc.ncbi.nlm.nih.gov/articles/PMC5526216/
https://my.clevelandclinic.org/health/body/the-gut-brain-connection
https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-brain-gut-connection
https://pmc.ncbi.nlm.nih.gov/articles/PMC9355758/
https://pmc.ncbi.nlm.nih.gov/articles/PMC3904694/
https://pmc.ncbi.nlm.nih.gov/articles/PMC11988747/
https://pmc.ncbi.nlm.nih.gov/articles/PMC12035109/
