Winter-Proof Your Immune System: Beyond Vitamin C

Every winter in the UK, many of us feel caught in a revolving door of colds, coughs, and bugs. If you find yourself asking, “Why do I always catch everything?”, the answer is rarely just bad luck. Your immune system is influenced by many interconnected factors - and the good news is, you can support them through simple food and lifestyle choices.

Let’s look at the science of immune resilience, and how you can give your body the tools it needs to thrive this winter.

Why We’re More Vulnerable in Winter

• Cold & dry air helps viruses survive longer.

• Indoor living increases close contact and exposure.

• Low sunlight reduces vitamin D, a key immune nutrient.

• Stress, sleep disruption & comfort eating often peak at this time of year

Four Key Influences on Immune Health

1. Stress

Stress hormones like cortisol suppress immune function when they remain high for too long. That’s why we often come down with a cold after a particularly stressful period.

Support it: Balanced meals to stabilise energy, daily movement, breathing practices, and restorative downtime all help regulate stress responses.

2. Gut Health

Around 70% of your immune system lives in your gut. A healthy, diverse microbiome is essential for strong defences.

Support it: Eat fibre-rich foods (beans, oats, veg), fermented foods (kefir, sauerkraut, kimchi), and plenty of colourful plants to feed gut microbes.

3. Sleep

Sleep is when your immune system “learns” and adapts. Research shows people who sleep less than 6 hours a night are far more likely to catch a cold.

Support it: Aim for 7–9 hours, keep a consistent sleep routine, reduce blue light in the evening, and include magnesium-rich foods (greens, nuts, seeds).

4. Nutrient Status

While vitamin C is important, it’s not the whole story.

Vitamin D is critical for immune regulation - yet deficiency is common in UK winters.

Zinc supports white blood cell activity.

Selenium, iron, omega-3s also play supportive roles.

Support it: Focus on nutrient-dense foods (salmon, pumpkin seeds, leafy greens, citrus, Brazil nuts) and consider a vitamin D supplement from October–April.

Top Foods for Immunity

• Mushrooms – beta-glucans to activate immune cells

• Citrus & berries – vitamin C & antioxidants

• Garlic & onions – prebiotics and natural antimicrobials

• Oily fish – vitamin D & omega-3 fatty acids

• Pumpkin seeds – rich in zinc

• Fermented foods – probiotics for gut health

• Dark leafy greens – folate & magnesium

You can’t avoid every virus out there, but you can build resilience. Small, consistent daily habits — like nourishing meals, good sleep, and stress support — add up to a stronger immune system over time.

Want practical support? Download my free guide “Eat to Beat Winter Bugs” for a 3-day meal planner and immune-boosting recipes