When was the last time you went all winter without getting sick?

In winter the days are long and dark, and our immune system has to work extra hard to protect us from all the germs and bugs poised to bring us down. One of the most common questions we get asked around this time is ‘how do I avoid getting sick?’

In this deep dive we’ll equip you with everything you need to know about boosting your resiliency, so you stay well for longer and recover faster.

We’ll be going deep into the topic, particularly around nutrition, and will share what the latest research has to say. You’ll leave with a strong understanding of the immune system and the ultimate protocol to stay well this winter. 

Your Immune System

Before we begin, it’s worth a quick recap of how our immune system supports us. Coming down with an illness can leave you feeling miserable, missing out on life, and generally less productive. For optimal health, your immune system should spot troublemakers like bacteria and viruses and launch the right response, producing antibodies to take them down. 

It does this by working with a coordinated network of cells and organs that split into two main defense teams. First, the fast-acting crew (including “clean-up cells” and “guardian cells”) jumps in to tackle threats in a broad way. Then, the “special forces” (specialised T and B cells) come on the scene to finish the job with pinpoint accuracy. Plus, they’ll remember those invaders for next time so you can bounce back even faster. 

Okay, so we know what the immune system does but without proper care it can falter. Leaving you vulnerable to attack. So what does science tell us about how to keep it running well, even in the middle of winter? There are two things we can look at here: diet and lifestyle. We’ll mainly focus on diet and nutrition, as that’s our specialty, but first, let’s touch on some other lifestyle factors that can also make a difference.

Stress and Immunity

We know stress can play a big role in our health and chronic stress can suppress the immune system, making us more susceptible to infections. A 2004 meta-analysis of over 300 studies found that long term stresses were consistently associated with suppression of the immune system. This is a challenging area since external stresses are often outside of our control. But creating moments of peace to calm the body’s stress response will go a long way to helping us stay well. Incorporating practices like meditation and yoga into our routine can be powerful tools to reduce stress and support overall health.

The Balancing Act of Exercise

Exercise is one of the most powerful, yet underutilised tools in our arsenal. The beauty of physical activity is that not only does it help support your immunity, but it also helps reduce stress, creating a positive spiral. Its potent effect on the immune system was highlighted in a 2007 study that demonstrated regular moderate exercise is associated with a reduced incidence of infection compared to a sedentary lifestyle.

However, do too much exercise and the effect can be reversed. The same study discovered that athletes who engaged in intensive periods of endurance training may be more susceptible to minor infections due to a temporary immune suppression. As with many things in life, balance is key here. 

Sleep: Your Immune System's Best Friend

How would you rate your sleep on a scale of 1 - 10? 

While most of us try to get good sleep, whether or not we succeed  can often feel outside of our control. Parents and shift workers will know that lower quality sleep has a big impact on your ability to function and fight off sickness But any efforts you can make to improve your sleep will go a long way to boost your resilience.

A 2011 study showed that sleep strengthens the immune system by helping T cells travel to lymph nodes and boosting the production of molecules that fight infections, improving the body's ability to recognise and respond to future threats. For optimal health, adults should aim for 7-9 hours of quality sleep each night. So setting an alarm to tell you when to go to bed might be just as important as the  one waking you up!

Nutrition

Now you know what lifestyle tweaks can help you stay well in winter, let’s get your nutrition sorted. We’ll explore the effects of specific nutrients on the immune system, providing insights into how dietary choices can build your defenses and give you the best chance of building resilience this winter. 

Vitamin D

Vitamin D is an important ally for a healthy immune system. When levels are low, you may become more vulnerable to colds and other respiratory illnesses. This is because vitamin D helps regulate immune responses and supports the body’s natural defenses against viral threats. In some cases, a deficiency can even increase the risk of recurrent infections. Keeping your vitamin D levels in check can be as simple as enjoying a little daily sunlight, eating nutrient-rich foods, and taking a vitamin D supplement.

Best of all, research confirms its benefits and a 2017 meta-analysis of 25 randomised controlled trials found that consistent vitamin D intake reduced the risk of acute respiratory infections by up to 50% among people with low vitamin D levels. Even those starting with higher levels still enjoyed a notable reduction in risk. These findings are reassuring and show that small, steady steps can go a long way toward feeling your best year-round.

Vitamin C

While ensuring enough vitamin D is a great start, vitamin C is another nutrient that can lend extra support to building your resilience in winter. It may not block every cold, but research shows it can help you bounce back faster. For instance, a 2013 review covering seven decades of clinical research found that daily vitamin C intake shortened colds by about 8% in adults and 14% in children. The research also concluded that vitamin C reduced the severity of the cold symptoms.

Incorporating vitamin C into your routine can be as simple as enjoying more fresh produce. Fruits like oranges, strawberries, and kiwi, as well as vegetables such as bell peppers and leafy greens, offer tasty ways to increase your intake. Whole food Vitamin C, made with fruit, is a balanced way to complement these foods and boost your intake.

Zinc

Building on the immune-boosting benefits of vitamins D and C, it’s also worth highlighting zinc, a key mineral that underpins healthy immune function. Zinc not only supports the growth and activity of immune cells, but it also has antiviral properties that can help keep seasonal bugs at bay. In particular, it’s been shown to inhibit the replication of rhinovirus, one of the main culprits behind the common cold.

Research suggests that starting zinc supplementation as soon as you notice the first sniffle can significantly reduce how long you feel under the weather. For instance, a 2013 review found that supplementing with zinc could shorten the duration of the common cold when started within a day of noticing symptoms. Another review published in 2019 highlighted that zinc supports antiviral immunity, indicating it may help our bodies respond more effectively to viral infections such as the flu. 

Selenium

Selenium is a trace mineral that is essential for immune function. It helps to protect cells from damage, supports the production of antibodies, and moderates inflammation. It is particularly effective at fighting viral infections, and one study found that selenium helps with the flu by strengthening the body’s natural defenses and allowing immune cells to respond more effectively.

If you are deficient in selenium, research suggests you’ll be more likely to pick up viral infections. The good news is that selenium supplementation has been proven to have antiviral effects in people with low levels, which is why it's important to ensure you're getting enough selenium in your diet.

Common sources of selenium include Brazil nuts, seafood, and meat. You only need about 1-2 Brazil nuts per day to meet your daily needs.

Probiotics

Our gut plays a crucial role in immune function, and research suggests that probiotics may help boost the immune system and build resilience against infections. A healthy gut microbiome is essential for a strong immune system, and probiotics can contribute to this balance.

A 2006 study found that probiotics significantly shortened the duration of cold episodes in adults by almost two days and reduced the severity of symptoms. Studies involving children have also shown promising results with one study concluding that probiotics reduced the likelihood of them developing common cold symptoms, including fever, cough, and runny nose.

Although it is not clear whether probiotics can prevent you from catching a cold or the flu, there is evidence that they reduce the duration and severity of these illnesses. They also appear to enhance immune responses, which may help explain these effects.

Functional Mushrooms

Functional mushrooms are another potent ally for a healthy immune system, especially throughout the colder months. These unique mushrooms contain specific compounds called Beta-1,3/1,6-glucans. Extensively researched, these beta-glucans are primarily known for their potent immune-supporting properties. They function by activating white blood cells, which strengthens the body’s natural defences. Laboratory studies have highlighted beta-glucans ability to help the immune system, reducing the frequency and symptoms of respiratory infections (like colds or the flu).       

Wrapping Up: Essential Nutrients for Immune Health

While there isn’t a single magic bullet for warding off every cold or bout of flu, getting enough of these key nutrients can give your immune system a helping hand and boost your ability to fight off infections. Here’s a handy rundown of each nutrient’s benefits and the everyday foods you can find them in:

Final Word

All in all, looking after your immune system and overall wellness during the colder months is a team effort, one that includes dialing down stress, finding an exercise balance, carving out sleep time and getting the right nutrients. From vitamin D and C to zinc, selenium, probiotics and chaga, each piece helps keep your defenses strong and ready for whatever winter throws your way. By embracing these simple, research-backed strategies, you’ll not only build a foundation of resilience but also set yourself up for more vibrant days, fewer sick days, and healthier, happier winter ahead.