How to Support Your Immune System Naturally: A Naturopath's Guide
By Kylie Sartori | Kylie Sartori Naturopathy, Spotswood Melbourne
Most of us only think about our immune system when we are already unwell.
The throat starts to scratch, the sniffles arrive, and suddenly, we are reaching for vitamin C and hoping for the best. But immune health is not something you build in the middle of a cold. It is something you build in the weeks and months before one arrives.
The good news is that the foundations of a strong immune system are the same foundations that support your energy, your gut health, your hormones, and your overall wellbeing. When you get those right consistently, your immune system tends to follow.
Here is where to start.
Why Your Gut Is the Centre of the Picture
If there is one thing worth understanding about immune health, it is this.
Approximately 70 to 80 percent of your immune system lives in your gut. The gut-associated lymphoid tissue, the community of immune cells lining your digestive tract, is your body's primary defence system. The bacteria living in your gut microbiome directly regulate how those immune cells behave, how they identify threats, how aggressively they respond, and how quickly they stand down once a threat has passed.
When your gut microbiome is diverse and balanced, your immune system is calibrated well. When it is disrupted, whether from antibiotics, a poor diet, chronic stress, or illness, your immune response becomes less precise and less effective.
This is why supporting gut health is central to supporting immune health, not a separate conversation.
If you would like to understand more about what is happening in your gut microbiome, you can read about functional testing and what investigating it looks like in practice.
Food First
What you eat provides the raw materials your immune system runs on.
Vitamins A, C, D, and E, along with zinc, selenium, and omega-3 fatty acids, are among the most important nutrients for immune function. They support the production of immune cells, regulate inflammatory responses, protect the integrity of the gut lining, and help the body recover faster when it does get sick.
A diet built around whole foods naturally provides most of these. Colourful vegetables and fruits, particularly berries, citrus, kiwi fruit, and leafy greens like broccoli, kale, cabbage, and brussels sprouts, are among the most nutrient-dense immune-supporting foods available. Quality protein from eggs, fish, chicken, legumes, and nuts provides the amino acids the body needs to produce antibodies and repair tissue. Healthy fats from olive oil, avocado, nuts, seeds, and oily fish reduce systemic inflammation and support the gut lining.
On the other side of the equation, processed foods, refined sugars, artificial sweeteners, alcohol, and fried foods suppress immune function, disrupt the gut microbiome, and drive the low-grade inflammation that makes the body more vulnerable to illness.
The most powerful immune supplement is still the food on your plate.
The Nutrients Worth Knowing About
Vitamin D
Vitamin D is essential for immune regulation and is one of the most consistently deficient nutrients in the Australian population, particularly through the winter months when sun exposure drops.
Low vitamin D is associated with increased susceptibility to respiratory infections, slower recovery, and a higher risk of autoimmune flares. Supplementation through winter is appropriate for most people, but getting your levels tested first means you can dose accurately rather than guessing.
Vitamin C and Zinc
These two work synergistically and are among the most well-researched nutrients for immune support. Vitamin C supports the production and function of white blood cells and acts as a powerful antioxidant in immune tissue. Zinc is essential for the development of immune cells, the integrity of the gut lining, and the resolution of inflammation.
Together, they have been shown to shorten the severity and duration of colds and respiratory infections, as well as reduce the likelihood of getting sick in the first place.
NAC (N-Acetyl Cysteine)
NAC is an amino acid precursor to glutathione, your body's most powerful antioxidant. It has strong antiviral and anti-inflammatory properties, is particularly well supported for upper respiratory infections, and is one of the most useful nutrients for thinning mucus and clearing the airways in conditions like bronchitis and sinusitis.
It is also one of the most underused nutrients in immune support, which is worth knowing.
Probiotics
Given how central the gut microbiome is to immune function, probiotic support through winter makes clinical sense. The most important thing is choosing the right strains for the right purpose. Not all probiotics are the same, and a general broad-spectrum probiotic is not always the most effective approach.
Fermented foods, including raw sauerkraut, kimchi, kefir, and yoghurt provide beneficial bacteria alongside the prebiotics and postbiotics that support the broader microbiome ecosystem. These are worth including regularly as food, not just as a winter strategy.
Herbal Medicine for Immune Support
Herbal medicine has a strong evidence base for immune support, and this is one of the areas where it genuinely shines.
Echinacea is one of the most well-researched herbs for reducing the frequency, severity, and duration of upper respiratory infections. It works best taken at the first sign of illness and consistently through the exposure period rather than as a one-off dose.
Elderberry has significant antiviral activity and is particularly useful for influenza. Research supports its ability to reduce the duration of flu symptoms and inhibit viral replication.
Astragalus is a deeply nourishing immune tonic that works best taken consistently over several weeks rather than acutely. It supports the innate immune system and is a good option for people who get sick frequently or take a long time to recover.
The right combination depends on your individual picture, your history of illness, any medications you are taking, and what your immune system specifically needs. This is where working with a naturopath makes a meaningful difference to outcomes compared with self-prescribing off the shelf.
Sleep Is Not Optional
During sleep, the body produces cytokines, immune signalling proteins that regulate both the inflammatory response and the body's ability to fight infection.
Poor sleep, whether that means less than seven hours, broken sleep, or consistently late nights, directly suppresses immune function. Studies show that people who sleep less than six hours a night are significantly more likely to develop a cold when exposed to a virus than those sleeping seven hours or more.
A consistent bedtime, a dark and cool room, screens off at least 30 minutes before bed, and avoiding caffeine after midday are the foundations. They are not glamorous, but they are genuinely more powerful than most supplements when it comes to immune resilience.
Stress and the Immune Connection
Cortisol, your primary stress hormone, directly suppresses immune function when it is chronically elevated.
This is not a design flaw. In the short term, cortisol helps the body manage acute stress by temporarily dialling down immune activity so resources can go elsewhere. The problem is when stress is persistent and cortisol stays elevated week after week. Over time, this impairs immune surveillance, increases susceptibility to infection, and slows recovery.
Managing stress is immune support. Practices like slow breathing, walking, yoga, swimming, and genuinely switching off have a measurable impact on cortisol and immune function. They are not lifestyle add-ons. They are part of the clinical picture.
You can read more about the adrenal and stress connection in my post on burnout and adrenal health.
A Note on Antibiotics and Over-the-Counter Medications
This comes up often in clinic and it is worth addressing directly.
Over-the-counter cold and flu medications manage symptoms but do not address the underlying infection. In some cases, suppressing symptoms like fever can actually prolong illness by interfering with the body's own immune response.
Antibiotics are sometimes necessary and when they are, they should absolutely be taken. But they do not work against viruses, which cause the majority of winter illnesses, and each course has a significant impact on the gut microbiome that takes time and targeted support to recover from.
If you have recently finished a course of antibiotics, supporting your microbiome with targeted probiotics and prebiotic foods in the weeks that follow is one of the most important things you can do for both your gut and your immune health going forward.
The Simple Daily Habits That Compound Over Time
Beyond the specific nutrients and herbs, the daily habits that most consistently support immune health are drinking at least two litres of water each day to support detoxification and mucosal immunity, reducing alcohol which directly suppresses immune function and disrupts sleep, minimising exposure to endocrine-disrupting chemicals in cleaning products, personal care products, and food packaging, and moving your body regularly in a way that supports circulation and lymphatic flow without overtaxing an already stressed system.
None of these are dramatic. But done consistently across the year rather than just when you feel a cold coming, they make a significant cumulative difference to how often you get sick and how quickly you recover.
Working Together
If you find yourself getting sick frequently, taking a long time to recover, or simply want to build a stronger foundation going into winter, we can work together to understand what your immune system specifically needs.
I see clients in person at my Spotswood clinic in Melbourne and via telehealth across Australia.
You can also explore what conditions I work with or find out more about functional testing if you would like to understand more before booking.
Frequently Asked Questions About Immune Health
Why do I keep getting sick even when I take vitamins? Frequent illness usually points to something deeper than a single nutrient deficiency. Poor gut health, chronic stress, disrupted sleep, and an imbalanced microbiome are among the most common underlying drivers. Supplements support an already strong foundation. They work less effectively when the foundations are not in place.
Is it worth getting a flu shot as well as taking natural immune support? Yes. Natural immune support and vaccination work through different mechanisms and are not mutually exclusive. Supporting your immune system through nutrition, sleep, stress management, and targeted supplements improves the overall terrain your immune system operates in, which benefits your response to both infection and vaccination.
How long does it take to rebuild the gut microbiome after antibiotics? Research suggests the microbiome can take anywhere from one to six months to recover after a course of antibiotics, depending on the antibiotic type, the duration of the course, and the state of the microbiome before treatment. Targeted probiotic and prebiotic support in the weeks following a course significantly speeds up that recovery.
What is the single most important thing I can do for my immune health? If I had to choose one thing, it would be sleep. Consistently getting seven to eight hours of quality sleep does more for immune resilience than almost any supplement. Everything else builds on top of that foundation.
Can stress really make me more likely to get sick? Yes, and the research is clear on this. Chronic stress suppresses the production and activity of immune cells, increases susceptibility to viral infection, and slows recovery time. Managing the stress load is not separate from immune support. It is central to it.
Kylie Sartori is a degree-qualified naturopath based in Spotswood, Melbourne, specialising in gut health, immune health, hormonal health, and family wellbeing. She offers in-person consultations at her Spotswood clinic and telehealth appointments for clients across Australia.
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