Nourish Your Immune System This Winter

“It’s the Most Wonderful Time of the Year” – a beloved Christmas classic released in 1963 – captures the magic of the season for many. With the holidays just around the corner, Christmas markets are bustling, dazzling lights brighten the streets, and festive preparations are well underway. Yet, for all the joy, one could argue that it’s also “the most snotty time of the year.” As the season unfolds, tissues (or hankies, depending on your generation) become an essential accessory. Nearly everyone knows someone battling a cold, the flu, or another seasonal ailment. For every corner offering mulled wine, there’s another echoing with a symphony of sneezes.

So, why do illnesses seem to spike during the colder months? Let’s take a closer look at the immune system, explore why winter sees more people under the weather, and discuss practical ways to strengthen our defences this season.

Firstly, what is the immune system? 

The immune system is our body’s intricate defence mechanism, comprising a network of cells, proteins, organs, and processes designed to protect us from illness. It operates diligently in the background, often going unnoticed until we face an infection or disease. 

The immune system has three primary tasks:

• Fighting off harmful germs, like bacteria and viruses, and removing them from the body.
• Recognising and neutralising harmful substances.
• Addressing disease-causing changes within the body, like cancerous cells.

Think of the immune system like a security guard: it detects intruders and responds to eliminate them. This system has two main components:

• Innate Immune System: This is our immediate response mechanism, providing non-specific defences against pathogens (disease causing organisms).
• Adaptive Immune System: This develops over time as we are exposed to various pathogens or through vaccinations. It creates specific responses tailored to particular invaders and retains memory for faster responses in future encounters.

When this defence system is compromised, an alarm is triggered, signalling for backup to help fight off invaders effectively.

Why does winter worsen colds and flu?

Winter’s chilly embrace not only calls for woolly scarves, hot drinks, and cosy fires but also brings a rise in respiratory illnesses. Here’s why:

• Cold Weather and Dry Air: Low temperatures and dry indoor air can dry out the mucous membranes in the nose and throat. This compromises their ability to trap and expel viruses, making it easier for infections to take hold.
• Reduced Vitamin D Levels: Shorter days and limited sunlight reduce vitamin D production, an essential nutrient for immune health. A deficiency can make you more vulnerable to colds and flu.
• Increased Close Contact: With more people indoors in crowded spaces, the spread of airborne viruses from coughing and sneezing is heightened. Poor ventilation also contributes to this increased transmission.

Together, these factors create an environment where germs can thrive and spread more easily. Maintaining a strong immune system becomes crucial during these months to fend off illness effectively or reduce its severity.

How does food impact immune health? 

While no single food or supplement can guarantee immunity, a well-balanced diet that meets your body’s energy needs is the cornerstone of a healthy immune system. Nutrients act as building blocks for immune cells and processes, supporting their ability to fight off pathogens. Conversely, diets high in processed foods and low in essential nutrients can weaken our defences and promote chronic inflammation which increases the risk of disease. To support your immune health, focus on maintaining a balanced diet rich in variety from whole foods by ensuring that your main meals include a source of protein, complex carbohydrates, healthy fats, and a colourful array of fruits and vegetables. 

My top 7 tips to feed your immune system this winter 

1. Prioritise Gut Health

Did you know that approximately 70% of the immune system resides in the gut? When I first learned this fact, it sparked my passion for studying nutrition - I found it fascinating! A healthy gut microbiome, rich in beneficial bacteria, plays a crucial role in regulating immune responses, as it houses the majority of our immune system. By nourishing our gut, we are effectively supporting our body’s defences against illness. Think of it as providing the “security guard” and other staff working hard to protect us with the fuel it needs to perform its job effectively.
To support your gut health, aim to incorporate the "3 Ps" into your daily diet: probiotics, prebiotics, and plants.

Probiotic Foods

Probiotic foods contain live bacteria that enhance gut health by introducing helpful microorganisms involved in various health-supporting activities. Examples include Greek yoghurt with live cultures, kefir, sauerkraut, kombucha, and kimchi. Regularly incorporating these foods into your diet can help populate your gut with beneficial bacteria.

Prebiotic Foods

Prebiotic foods serve as fuel for these good gut bacteria. They include garlic, onions, asparagus, bananas, oats, and chicory root. Consuming these foods regularly helps beneficial bacteria thrive and multiply, further enriching your gut microbiome.

Plant-Based Foods

Plant-based foods - such as fruits, vegetables, pulses, legumes, nuts, seeds, herbs, and spices - are excellent sources of fibre and antioxidants. Incorporating a diverse array of plant foods into your diet is associated with a gut microbiome that hosts a variety of beneficial bacteria. Aim for at least 30 grams of fibre daily to support gut health and promote regularity, which is key to eliminating harmful substances from the body.

By focusing on these three components - probiotics, prebiotics, and plant-based foods - you can nourish your gut and strengthen your immune system effectively! 

2. Load Up on Antioxidant-Rich Foods

Antioxidants are crucial for keeping the immune system strong and healthy. They act like the body's “defence squad” by neutralising free radicals which are unstable molecules that cause inflammation and weaken the immune system.  By supporting the production of infection-fighting cells and reducing stress on the body, antioxidants play a key role in helping us stay healthy and recover from illnesses.

Incorporating antioxidants into your diet is easier than you think. Start with vitamin C, a powerhouse that boosts white blood cell production and enhances skin barriers. Add citrus fruits, strawberries, or bell peppers to your meals. Next is vitamin E, which protects cell membranes and supports immune development—enjoy nuts, seeds, and avocado for a delicious dose. Selenium, a trace mineral, helps regulate immune responses and can be found in Brazil nuts and seafood. Don’t forget beta-carotene, which converts to vitamin A for healthy skin and mucosal barriers—load up on carrots, sweet potatoes, and leafy greens. Finally, flavonoids, found in tea, berries, and dark chocolate, bring anti-inflammatory benefits that support overall immune resilience.

Here are a few simple ways to increase your antioxidant intake throughout the day:

• Eat the Rainbow: Enjoy a variety of colourful fruits and vegetables.
• Snack Smart: Opt for a handful of mixed nuts and seeds.
• Beverage Swap: Replace one of your drinks with green tea.
• Indulge Wisely: Treat yourself to 70% dark chocolate as a sweet snack.

3. Embrace Healthy Fats

Healthy fats are essential for the absorption of fat-soluble vitamins (A, D, E, and K) and support the integrity of cell membranes, which is crucial for immune cell function. These fats are also anti-inflammatory, supporting the immune system.
Incorporate healthy fats into each meal by using extra virgin olive oil, enjoying 2-3 portions of responsibly sourced oily fish weekly (like salmon, mackerel, or sardines), or adding walnuts and chia seeds. For those who don’t consume fish, consider an algae oil supplement to ensure sufficient omega-3 intake.

4. Don’t Forget Protein

Protein plays a pivotal role in supporting the immune system and maintaining overall health. It is essential for the production of antibodies—specialised proteins that identify and neutralise harmful invaders like bacteria and viruses. Protein also aids in cellular repair and growth, ensuring that immune cells can regenerate and function optimally to combat infections. 

To maximise these benefits, it’s important to include a source of protein in every meal. This ensures a steady supply of amino acids, the building blocks of proteins, to support the immune system continuously. Great options include lean meats, poultry, fish, eggs, dairy, legumes, tofu, nuts, and seeds. For instance, pairing a salad with grilled chicken or adding beans to a vegetable soup can provide the protein your immune system needs to stay strong.

5. Boost Vitamin D Levels

Vitamin D plays a crucial role in immune health by helping regulate the immune system and promoting the production of antimicrobial proteins that fight off pathogens. It also has anti-inflammatory properties, reducing excessive inflammation that can occur during infections, and is associated with a lower risk of respiratory infections like colds and flu. The body naturally synthesises vitamin D when exposed to sunlight, but this may be insufficient during winter or in areas with limited sunlight. Food sources such as fatty fish (salmon, mackerel, sardines), cod liver oil, fortified foods, and egg yolks provide additional vitamin D. For those with limited sun exposure or dietary intake, vitamin D3 supplements are important. In the UK, a daily supplement of 10 micrograms is recommended during the darker months when sunlight is limited.

6. Consider Echinacea

Echinacea is a traditional herbal remedy believed to support the immune system. Studies suggest it may reduce the severity and duration of colds. Use it at the first signs of illness, following dosage instructions on reputable products.

7. Stay Hydrated

Hydration is essential year-round, but it becomes particularly important in winter when people often feel less thirsty. Adequate water intake supports circulation, allowing immune cells to travel efficiently throughout the body. Dehydration can thicken mucus, making it harder to expel pathogens and increasing the risk of respiratory issues. To stay properly hydrated, aim for pale yellow urine as a sign of good hydration, and incorporate water, herbal teas, and broths into your daily routine for both hydration and comfort during the colder months.

Additional tips to support immunity 

While nutrition lays a strong foundation, lifestyle habits also play a vital role:

• Exercise Regularly: Moderate exercise enhances circulation and immune function. Aim for at least 150 minutes per week.
• Get Quality Sleep: Prioritise 7–9 hours of restorative sleep each night, as this is when the body repairs and regenerates.
• Manage Stress: Chronic stress weakens immunity. Practice relaxation techniques such as meditation, deep breathing, or yoga.
• Practise Good Hygiene: Simple habits like regular handwashing reduce germ spread.

In summary 

While it’s important to focus on your health, remember that wellness is about balance, not perfection. Enjoy festive treats without guilt and rest when needed. Small, consistent steps - like adding more vegetables to your meals or enjoying a calming tea - can make a significant impact over time. If you struggle with a compromised immune system, prioritising a varied and balanced diet can provide crucial support.

Supporting your immune system isn’t about quick fixes or extreme measures. It’s about embracing sustainable, nourishing habits that fit your lifestyle. From eating nutrient-rich foods and staying hydrated to prioritising rest and reducing stress, these efforts build a strong foundation for health.

This winter, as you enjoy the festive season, don’t forget to give yourself the care and nourishment your body deserves. A resilient immune system not only protects you from illness but enables you to fully embrace the joys of the season.