Every year as the weather cools, like clockwork, the conversation turns to immune system health. The go-to defence seems to always start with vitamin C, cold and flu tablets, and zinc supplements.
But if you want to take a proactive approach to your immune health this winter, the most important place to start is somewhere most people overlook entirely. Your gut.
WHAT "70% OF YOUR IMMUNE SYSTEM LIVES IN YOUR GUT" ACTUALLY MEANS
You might have already heard this statement – but what does it really mean?
Your gut is home to a vast network of immune cells, antibodies and tissue that are continuously working to identify what's coming in through your digestive system. Every time you eat or drink, your gut immune system is making calls – distinguishing between the nutrients your body needs and the substances it needs to defend against. That process is happening every single day, whether you're paying attention to it or not.
THE BARRIER PROTECTING YOU IS JUST ONE CELL THICK
Your gut lining is one of your body's primary physical barriers against pathogens, and it's only one cell thick.
That single layer of epithelial cells is all that stands between the contents of your gut and your bloodstream, which means keeping that lining healthy isn't just a digestive priority – it's fundamental to how your immune system functions.
A compromised gut lining doesn't just affect digestion, it directly affects your body's ability to defend itself.
YOUR MICROBES PLAY A HUGE ROLE IN KEEPING YOU HEALTHY
The beneficial bacteria living in your gut don't just support the immune system passively – they help to train it. They help calibrate your immune responses, essentially teaching your immune system to distinguish between genuine threats and harmless substances.
A disrupted microbiome can affect that calibration, which is part of why researchers are increasingly looking at the microbiome as a foundation for immune health, not just digestive health.
WHAT YOU CAN ACTUALLY DO TO SUPPORT YOUR IMMUNITY
Start with your probiotic, but remember that not all strains are equal. What matters is whether the specific species and strain you're taking have clinical evidence behind them for immune health. Certain probiotic species, including Lactobacillus acidophilus and Bifidobacterium animalis, have published clinical research validating their role in supporting immune system health.
Beyond probiotics, diversity in your diet matters. The wider the variety of plants and fibres in your diet, the more diverse your microbiome – and a more diverse microbiome is a more resilient one. This doesn't need to be complicated. It could look like adding one new vegetable a week, eating different coloured produce, including legumes and wholegrains – small changes compound over time.
And be consistent – think long game, not a two-week sprint before winter hits or a two-day sprint before a trip overseas. Your microbiome responds to what you do every single day. Supporting a healthy gut should be a daily practice, not a seasonal one.
THE BOTTOM LINE
Supporting your immunity isn't about a quick fix – it's about prioritising your gut as the foundation of your overall health day in and day out.
The research is clear – your gut and your immune system are closely interlinked, not isolated mechanisms, and we need to start treating them that way.
GUT+ DIGEST is formulated to support both digestive health and immune system health.
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SOURCES
Mabbott, N.A., et al. "Human gut-associated lymphoid tissues (GALT); diversity, structure, and function." Mucosal Immunology, vol. 14, 2021, pp. 793–809. https://www.nature.com/articles/s41385-021-00389-4
Peterson, L.W., and D. Artis. "Intestinal epithelial cells: regulators of barrier function and immune homeostasis." Nature Reviews Immunology, vol. 14, no. 3, 2014, pp. 141–153. https://www.nature.com/articles/nri3608
Yao, X., et al. "Epithelial-immune cell crosstalk for intestinal barrier homeostasis." European Journal of Immunology, 2024. https://onlinelibrary.wiley.com/doi/full/10.1002/eji.202350631
Wiertsema, S.P., et al. "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, vol. 13, no. 3, 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC8001875/
"Lactobacillus acidophilus 74-2 and Bifidobacterium animalis subsp. lactis DGCC 420 modulate unspecific cellular immune response in healthy adults." European Journal of Clinical Nutrition, 2007. https://www.nature.com/articles/1602761
Jaime-Lara, R.B., et al. "Understanding dysbiosis and resilience in the human gut microbiome: biomarkers, interventions, and challenges." Frontiers in Microbiology, 2025. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1559521/full