The gut microbiome – an ecosystem of bacteria and other microorganisms living within the digestive tract – is closely intertwined with the body’s immune system. In fact, around 70-80% of immune cells are found in the gut[1]. This means gut health may influence immune cell development and how effectively the body responds to infection.
Our microbiome also plays a crucial role in metabolism: supporting digestion, producing essential vitamins, and protecting against harmful pathogens[2]. When the gut microbiota is balanced, it helps regulate inflammation and sustain a resilient defence system. However, if this balance becomes compromised – through stress, poor diet, antibiotics, or illness – the immune system may weaken, increasing susceptibility to infections. Recognising and nurturing this gut–immune connection is an important step towards long-term wellness.
Why the Gut Microbiome Matters for Immunity
The gut microbiome plays a vital role in shaping and training the immune system. By exposing immune cells to a wide variety of bacteria and microorganisms, it teaches them to distinguish between harmful, invading pathogens and friendly microbes[3]. Additionally, research suggests that the gut microbiome helps build "immune tolerance", reducing overreaction to non-harmful substances throughout the body[4].
Another important aspect is the gut-brain axis, which is a complex, bidirectional communication network linking the gut and the brain. This dialogue takes place through neural, hormonal, and immune pathways, connecting the central nervous system (CNS) with the enteric nervous system (ENS), often called the "second brain." The gut microbiota produce neurotransmitters, hormones, and other bioactive compounds that can influence brain function, mood, and behaviour. In turn, signals from the brain can impact gut motility, secretion, and immune activity. To learn more about the gut-brain axis, read our blog here.
Together, these interactions highlight the far-reaching influence of the gut on both immunity and overall health. However, further research is still needed to fully unravel the complexity of these relationships.
Improving Gut Health to Boost Immunity
Looking after your gut health doesn’t need to be complicated. Small, consistent changes to your diet and lifestyle can have a meaningful impact on the balance of your microbiome and, perhaps in turn, the strength of your immune system.
From adding fibre-rich foods to considering targeted gut health supplements, each step plays a role in nurturing a healthy gut environment. Below are some practical steps you can take to support both your digestive health and your body’s natural defences.
1. Eat a Diverse Diet
Eating the right foods is one of the most effective ways to nurture a healthy gut microbiome. Aim for variety and balance, as diversity in your diet encourages diversity in your beneficial bacteria. Some top choices include:
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High-fibre foods: Whole grains, oats, beans, lentils, chickpeas, and vegetables such as broccoli, carrots, and spinach.
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Prebiotic-rich foods: Foods like onions, garlic, leeks, and asparagus provide inulin and other fibres that nourish the microbiome.
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Fermented foods (natural probiotics): Yoghurt, kefir, sauerkraut, kimchi, miso, and kombucha contain beneficial bacteria that can support gut balance.
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Polyphenol-rich foods: Green tea, berries, and olive oil offer antioxidants that bacteria thrive on while reducing inflammation.
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Omega-3 sources: Oily fish (such as salmon, mackerel, and sardines), walnuts, and flaxseeds may help balance the microbiome and support immune function.
For a deeper dive into the herbs, vitamins, and minerals that can further strengthen your immune system, explore our full blog here.
2. Support Digestion
Digestive enzymes play a key role in breaking down food into nutrients that the body can absorb and use. While the body naturally produces enzymes, factors such as stress, illness, or poor diet may reduce their efficiency, leading to bloating, heaviness, or sluggish digestion. Supporting enzyme activity can help optimise nutrient absorption and ease discomfort after meals.
One way to encourage healthy digestion is through traditional herbal bitters. Napiers Best British Bitters is a classic herbal digestif that has been used traditionally to support the digestive process. It may be especially helpful after overindulgence in alcohol, rich or spicy food, or shellfish, as it stimulates the production of saliva and bile, aiding the breakdown of food. When taken before meals, it can also act as an aperitif, gently boosting appetite, which is particularly useful for those who have lost their appetite. Its liquid tincture format makes it easy to mix with water or juice. Incorporating herbal bitters into your routine can complement dietary and probiotic approaches, offering an additional layer of support for both gut comfort and overall digestive resilience.
3. Add Prebiotics and Probiotics
Prebiotics (fibres that feed bacteria) and probiotics (live bacteria) support a healthy and thriving gut microbiota. One way these can be incorporated into your daily routine is through supplementation. A great option is Napiers Phytologic Happy Gut Capsules.
These capsules combine:
- 20 billion friendly bacteria across 10 diverse strains
- Inulin and FOS prebiotics
- Digestive enzymes for nutrient breakdown
- Vitamin D3 (NHS recommended dose) for immune and gut interaction support
- Vegetarian-friendly, GMO-free formula
When taken regularly, they may help maintain a balanced gut environment where beneficial bacteria can thrive, supporting digestive comfort and immune resilience. For best results, take 1–3 capsules daily with food. We recommend starting with 1 capsule for the first 3–4 days, then increasing to 2 capsules for the next few days, and up to 3 if needed. This gradual approach allows your gut to adjust comfortably.
4. Manage Stress and Sleep
Studies have shown that stress and poor sleep may reduce microbial diversity and compromise immune balance[5]. Incorporating daily stress management strategies may make a significant difference. Practices such as mindfulness, yoga, or simply spending time outdoor may help calm the nervous system and reduce the impact of stress on the gut. Gentle exercise, like walking or stretching, typically supports circulation and digestion without overloading the body.
It is just as important to create a consistent sleep routine: aiming for 7-9 hours of restful sleep each night may help restore balance[6], giving both the gut and the immune system time to repair and regenerate.
5. Limit Unnecessary Antibiotics
While antibiotics are sometimes essential, they can disrupt the microbiome. Research indicates that this disruption may affect microbial diversity[7], so when antibiotics are prescribed, it can be helpful to include probiotic-rich foods or supplements to help restore balance afterwards.
6. Hydration
Hydration is often overlooked but is essential for digestive and immune health. Water supports nearly every function in the gut, from breaking down food and transporting nutrients, to maintaining the protective mucosal lining that shields the intestines from harmful pathogens. Without enough fluid, digestion may slow down, leading to constipation and discomfort, while the balance of the microbiome may also be affected.
For most people, aiming for 6–8 glasses of water a day is a good target, though needs vary depending on activity levels, environment, and individual health. Limiting excessive caffeine and alcohol is equally important, as both can be dehydrating and irritate the gut.
7. Fresh Air
Spending time outdoors provides more than just a mental reset – it can directly and indirectly benefit gut and immune health. Exposure to natural environments introduces us to a wider variety of microbes, which may help diversify and strengthen the gut microbiome. Regular contact with nature has also been linked to reduced inflammation and improved resilience against stress, both of which play a role in maintaining immune balance.
Fresh air and natural light may help regulate circadian rhythms, improving sleep quality, which in turn supports digestion and immunity. Even simple habits, like a daily walk in the park, gardening, or opening windows to ventilate indoor spaces, may make a difference. Pairing fresh air with light physical activity may further encourage healthy circulation and bowel motility, supporting overall gut function.
8. Professional Guidance
If you are looking for advice surrounding your gut health or wish to tailor your approach, Napiers offer various services that aim to support you with practical, personalised wellness strategies. Book a consultation with us to receive personalised guidance based on your individual health profile.
For more detailed information on immunity and additional tips, check out our immune health guide.
As well as your immunity, your gut may also influence your mental health. To learn more, read our blog on the connection between gut health and mental health.
FAQs
What is the role of gut microbiota in immunity?
Gut microbiota helps regulate immune responses, supports immune cell development, and balances inflammation to prevent overreactions.
How do I check my gut health?
There’s no single test for gut health, but signs such as irregular digestion, bloating, and unsteady energy can indicate unbalance. For a deeper assessment, practitioners may recommend stool tests to examine microbial diversity or food sensitivity testing.
What drink is good for gut health?
Hydration is key—water supports digestion and nutrient absorption. Fermented drinks such as kefir, kombucha, and probiotic-rich yoghurt drinks can introduce beneficial bacteria, while herbal teas like peppermint, ginger, or chamomile may soothe the digestive tract and reduce inflammation.
When should I seek professional help?
If you experience ongoing digestive issues, compromised immunity, or wish for a tailored plan, speaking with a specialist at the Napiers clinic can be very beneficial.
The gut microbiome is closely connected to the immune system, shaping how the body responds to infection and inflammation. Nurturing gut health through a varied diet, probiotics, good sleep, stress management, and mindful use of antibiotics can help strengthen both digestion and immunity.
References
- Wiertsema, S.P., van Bergenhenegouwen, J., Garssen, J. and Knippels, L.M.J. (2021) "The Interplay between the Gut Microbiome and the Immune System in the Context of Infectious Diseases throughout Life and the Role of Nutrition in Optimizing Treatment Strategies", Nutrients, 13(3), pp. 1-14. Available at: NCBI.
- Bajić, D., Todorović, N., Popović, M.L., Plazačić, M. and Mihajlović, A. (2025) "Immunity's core reset: Synbiotics and gut microbiota in the COVID-19 era", Innate Immunity, 31, pp.1–9. Available at: NCBI.
- Suchiita, A., Gupta, N., Nandi, K., Sonkar, S. and Chandra, L. (2025) Harmony within: Unravelling the microbiome–immune system symbiosis for health, Advanced Gut & Microbiome Research [online]. Available at: Wiley.
- Shao, T., Hsu, R., Rafizadeh, D.L., Wang, L., Bowlus, C.L., Kumar, N., Mishra, J., Timilsina, S., Ridgway, W.M., Gershwin, M.E., Ansari, A.A., Shuai, Z. and Leung, P.S.C. (2023) "The gut ecosystem and immune tolerance", Journal of Autoimmunity, 141, p.1-18. Available at: ScienceDirect.
- Wankhede, N.L., Kale, M.B., Kyada, A., Rekha, M.M., Chaudhary, K., Naidu, K.S., Rahangdale, S., Shende, P.V., Taksande, B.G., Khalid, M., Gulati, M., Umekar, M.J., Fareed, M., Kopalli, S.R. and Koppula, S. (2025) "Sleep deprivation-induced shifts in gut microbiota: Implications for neurological disorders", Neuroscience, 565, pp.99–116. Available at: Science Direct.
- NHS. Sleep Problems. Available at: NHS.
- Lathakumari, R.H., Vajravelu, L.K., Satheesan, A., Ravi, S. and Thulukanam, J. (2024) "Antibiotics and the gut microbiome: Understanding the impact on human health", Medicine in Microecology, 20, pp. 1-8. Available at: Science Direct.
