How The Gut Biome Impacts Your Physical and Mental Health: The Hidden Connection Between Digestion and Depression

Is Your Gut Secretly Sabotaging Your Mood?

Have you ever felt like your mood swings are out of your control, or that your energy just doesn’t match your active lifestyle? The answer might be hiding in your gut, where trillions of tiny organisms are working tirelessly to keep you balanced—or tipping the scales against you. Remarkably, approximately 57% of the cells in your body are bacterial, with only 43% being human. These microorganisms, known as the gut microbiome, aren’t just passengers—they’re key players in your health, especially when it comes to your mood and mental wellbeing.

The Gut-Brain Connection: How Your Gut Affects Mental Health

One of the most astonishing aspects of the gut is that up to 95% of your body’s serotonin—the neurotransmitter often referred to as the "happy hormone"—is produced in the gut, not the brain. This means that the health of your gut directly influences your mood, linking gut health to conditions like depression and anxiety. So, how exactly does your gut microbiome impact your physical and mental health? Let’s dive in.

Why Gut Bacteria Are Key to Your Digestion and Mental Health

Think of your gut as a bustling city where every microorganism has a job to do. Some produce essential vitamins like B12 and K, while others break down fibre into molecules that help regulate metabolism and immune function. But here’s the catch: without these bacteria, your body can’t fully digest or absorb the nutrients from your food. This means your gut bacteria are not just involved in digestion—they’re crucial for your overall health, including your mental health.

The Connection Between Diet, Gut Health, and Overall Wellbeing

A groundbreaking study shows just how much diet impacts gut health. Researchers had two groups—one from rural Africa, the other from the urbanised West—switch diets for just two weeks. The African participants adopted a Western diet high in fat and low in fibre, while the Westerners ate a traditional African diet rich in fibre and low in fat.

The results were astonishing. The African participants, who started with a diverse and healthy gut microbiome, saw a significant decrease in beneficial gut bacteria and an increase in markers associated with inflammation and disease. Meanwhile, the Western participants saw improvements in their gut health, including an increase in beneficial bacteria and a reduction in inflammation.

This study highlights the profound impact of diet on gut health—and how quickly our gut bacteria can respond to dietary changes. A diet high in processed foods and low in fibre can disrupt the balance of your gut microbiome, leading to a cascade of negative health effects, including mood disturbances and mental health challenges. A Personal Experience: Navigating the Effects of Gut Imbalance

In 2018, I was prescribed two rounds of antibiotics to treat an infection. While these medications were essential for addressing the issue, I noticed some unexpected changes in my health afterwards. Over time, I began experiencing a range of symptoms, including anaemia, chronic fatigue, frequent bruising, changes in my hair, and, unexpectedly, depression.

Tests revealed that I was severely low in iron and vitamin D, which was surprising given my active, outdoorsy lifestyle. Although my vitamin levels were eventually restored, the symptoms persisted, and the underlying cause remained elusive. It wasn’t until a nurse recommended that I consult with a functional health practitioner, who specialized in gut health, that we uncovered the root of the issue. Further testing revealed that the antibiotics had significantly reduced several vital species of gut bacteria, allowing less beneficial ones to dominate. This imbalance was affecting my health both physically and mentally. While antibiotics were essential in eradicating the infection, they also unintentionally disrupted my gut microbiome, highlighting the importance of supporting gut health during and after treatment.

With guidance, I began to restore balance to my gut microbiome. This included a tailored diet rich in fibre, probiotics to help repopulate the healthy bacteria and a wellbeing routine that supported my recovery. Slowly but surely, my health improved, and I began to feel like myself again.

Ways to Support a Healthy Gut

Many aspects of modern life can negatively impact the gut microbiome. I discovered antibiotics, while lifesaving in many situations, can also indiscriminately kill off beneficial bacteria along with harmful ones, leading to imbalances that may affect digestion, immunity, and mental health. Aspects of every day life such as stress and heavily processed foods can also alter gut function and reduce the diversity of beneficial bacteria. Supporting our gut health and restoring our gut forna is essential for good health and wellbeing. Here are 5 ways to support healthier digestion:

1. Eat a diverse range of foods: Include plenty of fruits, vegetables, and whole grains in your diet to nourish your gut bacteria.

2. Incorporate fermented foods: Foods like yogurt, kefir, sauerkraut, and kimchi are rich in probiotics that can help boost your gut health.

3. Consider probiotics: Supplements may help restore balance, especially after taking antibiotics, but it’s best to consult with a healthcare provider.

4. Limit processed foods: High-fat, low-fiber diets can harm your gut bacteria, so focus on whole, nutrient-rich foods instead.

5. Stay active: Regular exercise can promote a healthy gut by enhancing the diversity of your microbiome. Disclaimer: This blog is intended for informational purposes only and reflects personal experiences. It is not meant to provide professional medical advice. If you are looking for further information, please consult your GP, or check out the resources below.

Trusted Resources for Gut Health in the UK

Whether you’re looking to boost your overall wellbeing or manage specific gut-related issues, the latest research on the gut biome is a vital component of understanding mental health. Here are two trusted UK-based resources where you can explore more about gut health:

1. The Gut Health Doctor- Dr. Megan Rossi, also known as "The Gut Health Doctor," is a leading expert in gut health. Her website offers practical, science-backed advice, including blog posts, recipes, and guides to help you improve your gut health and overall well-being.

2. NHS – Digestive Health The NHS provides a wealth of information on maintaining digestive health, including tips on diet, lifestyle changes, and when to seek medical advice. Their resources are reliable and accessible to everyone in the UK.

References

1. Sender, R., Fuchs, S., & Milo, R. (2016).Revised estimates for the number of human and bacteria cells in the body.PLoS Biology, 14(8), e1002533. Link: https://doi.org/10.1371/journal.pbio.1002533

2. Yano, J. M., Yu, K., Donaldson, G. P., Shastri, G. G., Ann, P., Ma, L., ... & Hsiao, E. Y. (2015).Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis.Cell, 161(2), 264-276. Link: https://doi.org/10.1016/j.cell.2015.02.047

3. Mayer, E. A., Tillisch, K., & Gupta, A. (2015).Gut/brain axis and the microbiota. The Journal of Clinical Investigation, 125(3), 926-938.Link: https://www.jci.org/articles/view/76304

4. O’Keefe, S. J., Li, J. V., Lahti, L., Ou, J., Carbonero, F., Mohammed, K., & Zoetendal, E. G. (2015). Fat, fibre and cancer risk in African Americans and rural Africans. Nature Communications, 6(1), 6342. Link: https://doi.org/10.1038/ncomms7342