When I was 14, I fell into a deep depression with suicidal thoughts, triggered by the birth control pill. I stopped smiling, lost all joy in eating (yes, me), and I remember telling my mum, “It feels like something else is controlling me. This isn’t me.”
Years later, during my divorce, it happened again.
I woke up with no motivation and no energy to work. I often cried, felt helpless, and was deeply disappointed in myself for having misjudged someone so completely. I was functioning and making sure things got done. I am immense grateful for my morning habits that I had built over the years, which kept me somewhat grounded. But even the smallest tasks took immense effort.
Eventually, I realised I couldn’t do it alone anymore. I reached out for help to a psychotherapist, a Somatic Experiencing practitioner, and later to a mentor. One of the most healing shifts was reclaiming my self-responsibility for my life and choosing not to be in victim mode. Because otherwise I handed my power away. I am also forever grateful to my supportive friends.
Depression is not a weakness nor a personal failure.
It is a call from the body saying: “Something needs to change.”
And therefore has to be taken seriously.
Sometimes what needs to change is psychological. Yet more often than one might think, psychology alone isn’t enough. Because the real causes lie elsewhere.
What I did not learn at University
During five years studying psychology, I did not learn that a vitamin D deficiency or gut dysbiosis can also contribute to depression.
We never talked about other nutrient deficiencies, inflammation, or the gut–brain axis.
We didn’t discuss how thyroid dysfunction or poor sleep can disrupt the delicate balance of neurotransmitters and hormones that influence our mood.
We didn’t learn that 90-95% of serotonin is produced in the gut. While serotonin made in the gut doesn’t travel to our brain, it can activate the vagus nerve, which directly communicates with brain areas involved in mood regulation.
When someone comes with depression, they are often prescribed antidepressants, therapy, or both, especially for moderate to severe cases. But these treatments have their limits. Meta-analyses show that only about 40-60% of people reach full remission, meaning complete freedom from symptoms.
A comprehensive check-up (blood values, hormones, microbiome, nutrition, lifestyle) can open new doors, especially if therapy has only been partially effective so far.
Depression Has Many Roots
Depression rarely has a single cause. It emerges from the interaction of different factors:
🧬 Genetics: A predisposition may exist, but genes only express under certain conditions.
💔 Psychosocial stress: Loss, trauma, loneliness, discrimination, chronic stress.
💊 Medication and substance use: Birth control, alcohol, drugs, cortisone, betablockers.
🧠 Neurobiology: Dysregulated neurotransmitters, chronic activation of the stress axis.
🌡️ Chronic inflammation: Low-grade inflammation is increasingly seen as a biological root of depression.
🌿 Hormonal imbalance: Postpartum changes, thyroid dysfunction, menopause.
🥦 Nutrition and deficiencies: Vitamin D, B12, B6, B3, folate, iron, zinc, and magnesium are all required for serotonin production.
🌙 Lifestyle: Lack of sunlight, movement, and restorative sleep.
🌾 Gut health: Dysbiosis, poor fibre intake, highly processed food.
When these factors interact, even a resilient mind can start to crumble. That’s why I advocate for a holistic assessment.
The Forgotten Connection: The Gut–Brain Axis
Our gut has its own nervous system, often called the “gut brain.” It communicates directly with the emotional centres of our brain.
If the gut flora is disturbed, this connection becomes more dysregulated. It sends more stress and inflammatory signals rather than beneficial ones.
Studies found that people with depression often have reduced microbial diversity and fewer anti-inflammatory bacteria, such as Faecalibacterium and Coprococcus (which produce anti-inflammatory SCFAs). Research into the role of the microbiome in mental illness is still young. There are for example keystone species such as Bifidobacterium longum NCC3001 that protect against anxiety and depression and other neuro-inflammatory conditions.
Everything that happens in the gut such as inflammation, imbalance, and poor digestion can influence how we feel.
When we constantly feel bloated, tired, and foggy, the body is already sending signals of imbalance. Smelly gas, daily bloating, or sluggish digestion are not normal! They are messages.
Because if our gut cannot absorb nutrients properly, our brain won’t receive what it needs to make serotonin, melatonin, dopamine, and other mood-regulating chemicals.
Vitamin D and morning sunlight
UV-B radiation from sunlight triggers vitamin D synthesis in the skin. This is the primary natural source for most people. However, modern lifestyles often limit our sun exposure. We spend more time indoors, wear more clothing, use sunscreen, and live in areas with pollution that blocks UV-B rays.
With global mobility, many people now live in regions where the sunlight is not ideally matched to their skin tone. Skin colour also influences how efficiently we produce vitamin D. Lighter skin allows faster vitamin D synthesis, while darker skin offers more natural protection against strong sunlight. Meaning it needs much more sun exposure to produce the same amount of vitamin D.
In Switzerland, from November to April, the sun’s zenith angle is so low that UV-B radiation is insufficient for vitamin D production. During these months, 60–70% of the Swiss population is deficient in vitamin D, even among those who already supplement. This holds true for all regions located above 37–40° north latitude, whereas the length may differ. In addition, the skin’s ability to produce vitamin D naturally declines with age.
For these reasons, I highly recommend supplementing vitamin D from September to April for everyone living in Switzerland.
Low vitamin D levels are strongly linked to depressive symptoms, partly because vitamin D ensures that the brain has enough enzymes to convert L-tryptophan, an essential amino acid found in foods like soy, quinoa, nuts, and seeds into serotonin. Vitamin D also has anti-inflammatory properties.
If a deficiency is confirmed, supplementing vitamin D and simply getting more morning sunlight can significantly improve mood and regulate sleep rhythms (circadian rhythm).
Light therapy (10,000 lux), by the way, is one of the most underestimated antidepressants and works very well for Seasonal Affective Disorder (SAD).
The Power of Movement and Nature
Regular physical activity increases the production of serotonin, dopamine, noradrenaline, and endorphins. Lack of exercise increases chronic inflammatory markers (e.g., CRP, interleukins).
Movement also increases the growth factor BDNF (Brain-Derived Neurotrophic Factor), which helps the brain form new nerve cells and to escape rigid, negative loops.
Even a 20-minute walk in nature can start changing brain chemistry. The combination of daylight, movement, nature, and fresh air is like medicine. Not easy when you do not feel in the mood, but it is free and profoundly effective.
Nature shifts us from sympathetic (fight-or-flight) to parasympathetic (rest-and-digest) mode. This is why “forest bathing” (Shinrin-Yoku) is increasingly used in mental health treatment.
A Vicious and a Healing Cycle
Depression weakens the immune system.
We move less, eat less nutritiously, the quality of our sleep decreases, withdraw from others which then further fuels inflammation and deepens the depression.
But the opposite is also true:
Small, loving changes in lifestyle can start a healing spiral.
- Eating more plants (diversity in fiber feeds microbial diversity).
- Checking key nutrients and replenishing what’s missing.
- Spending time outside daily.
- Practising gentle movement instead of perfection-driven workouts.
- Feeling emotions instead of suppressing them.
- Thinking about someone who loves you. Meeting or calling a friend.
- Creating meaningful goals.
- Experiences of self-efficacy.
Healing means learning to distinguishing between your body’s genuine needs and depression’s distorted messages (“I am worthless”, “I have no energy so I shouldn’t do anything”, “Nothing matters”), responding with compassionate action rather than passive compliance, and gradually rebuilding trust in your inner guidance as symptoms decrease.
Healing Is Possible
Even after years of depression, the brain, microbiome, hormones and self-perception can regenerate.
If you’re struggling right now, please know:
It’s not your fault. You are not broken.
Your body is asking for care.
Sometimes antidepressants are necessary to break the vicious cycle and find stability again. Yet, there are also natural plant remedies that can offer a similar, though gentler, effect without the side effects and are worth trying first.
Have you ever suffered from depression, and what helped you?
Minimalist Traveller 
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