Although experts agree there’s “no magic fix”, and the term “immune-boosting” is overused, there are ways you can look after your immune system to give yourself the best chance of fighting off future infections. So in addition to having the flu jab and booster vaccines, what else can we do to steel ourselves health-wise ahead of the new season?
Here’s our expert-approved guide.
You should aim to get your essential nutrients from food sources. Your main goal? To avoid deficiencies in vitamin A, C, D, E and K, zinc, selenium and iron. “This doesn’t mean taking supplements, as more doesn’t mean better if you are not deficient,” says immunologist Jenna Macciochi, author of Immunity: the science of staying well. Next, you want to support gut health with a diet rich in different fibre sources. “Seventy per cent of the immune system is found in the gut — this is where gut bugs educate and regulate our immune system,” Macciochi explains. An easy way of doing this is to switch up your weekly shopping list to include a wider variety of fruit, veg, beans, pulses, nuts, seeds, herbs and spices. “These also contain lots of antioxidants, anti-inflammatory, antimicrobial nutrients like polyphenols, curcumin and carotenoids which all support immune function. And get enough protein, as this provides the building blocks for immune cells and antibodies.”
What specific foods should you look for? Chelsea-based nutritional therapist Alice Mackintosh, founder of supplement brand Equi London, says: “Vitamin C is essential for white blood cell production, and many studies have shown that getting at least 250mg daily can ameliorate symptoms and shorten the duration of colds and flu. The body is unable to store it so we need a daily supply.” Rich sources include citrus fruit, broccoli, kale, sprouts, sweet potatoes, butternut squash and peppers, as well as fresh herbs such as parsley. “Vitamin A is vital for supporting the immune system and is found in liver, meat, fish, seafood, eggs, chillies and spinach,” says Mackintosh. While “Zinc helps to support us by promoting the production of antibodies that skilfully remember the details of intruders previously defeated so we can fight them again.” Zinc-rich foods, like poultry, sunflower and pumpkin seeds, chickpeas, cashew nuts, seafood and fish, have the added bonus of being high in protein. Mushrooms, meanwhile, particularly oyster, shiitake and medicinal mushrooms such as cordyceps, reishi and maitake, contain potent immune-supporting “beta-glucans”. Add them to meals, along with garlic (which has antibacterial and antiviral properties), ginger (antimicrobial and anti-inflammatory) and antioxidant-rich and anti-inflammatory spices like cinnamon and turmeric, she recommends.
When to sup
Vitamin D is one of the few nutrients we struggle to obtain enough of from our diet. Usually, we produce it when our skin is exposed to sunlight, so the NHS recommends we supplement (10 micrograms per day) in the darker winter months from October to March. “Some people may benefit from year-round vitamin D supplementation depending on age, skin colour and time spent outside,” Macciochi says. She also recommends an omega 3 supplement if you don’t eat any oily fish, “it’s an important anti-inflammatory fat that helps turn off unwanted immune responses and lower unwanted inflammation. I’d also keep vitamin C and zinc in the house for when you do fall sick — these don’t need to be taken every day but can reduce symptoms.”
Probiotic foods like sauerkraut, kimchi, kefir and live yoghurt are known to help support gut health, but if you don’t consume these foods regularly, you may want to consider taking a probiotic supplement which can help to readdress the balance of friendly bacteria in the gut. “The beneficial bacteria that reside in the gut are our first line of defence, on which the immune system is highly reliant,” says Mackintosh. “Given our bacteria is so sensitive to what we eat, stress levels and medication such as antibiotics, it’s no wonder that it can easily become imbalanced, putting our immunity at risk.” If you do choose to supplement, Equi London’s Immunity Edition (£33 for a 30-day supply) contains a blend of vitamin D, reishi mushroom extract, probiotics and other protecting and nourishing vitamins and herbs.
Partaking in consistent, moderate exercise is a great way of steeling yourself ahead of flu season. “The immune system is really responsive to exercise,” says functional medicine practitioner and sports scientist Pete Williams, founder of Functional Medicine Associates. “The increase in blood flow and pressure that comes from exercise creates a better exchange of blood and lymph, increasing the ability to deliver cells around the body, a term we call ‘immunosurveillance.’” Moving daily has a “training effect” on the immune system, making it “much more ready for battle when needed,” he adds. And that doesn’t have to mean hours in the gym. “Even short periods of exercise can lead to more immune cells maturing out of the places that they are developed and into the bloodstream, those fresh immune cells are good at combating bugs and pathogens,” says Ryan Thwaites, an immunologist at Imperial College London. Which type of exercise is best? Simply put, pretty much anything that elevates your heart rate and body temperature. That could be jogging or a Pilates or Yoga class that gets your heart pumping a little. Strength training is crucial, too. “Muscle mass is really important to immune health so aim to incorporate at least two muscle strengthening exercises into your week,” Macciochi advises, “and be sure to get up from your desk regularly and break up sedentary periods.”
Factor in self-care
Addressing other lifestyle factors, such as stress levels and sleep quality, is all part of the immune health picture, too. “Sleep is huge in how well our immune system works — aim for between seven and nine hours, stick with a consistent bedtime and wake time and be sure to get some sunlight during the day to help you regulate your circadian rhythm,” says Macciochi.
Adopting a regular meditation practice could also help. A 2016 review looked at the effects of mindfulness meditation on the immune system and found possible promising effects on inflammation, cell-mediated immunity and biological ageing. If you’re not already familiar with the Wim Hof method, there could even be a benefit in taking a cold shower first thing — another larger study found that a routine cold shower reduced the number of sick days taken by employees by 29 per cent. Taking the odd bone-warming sauna and going for a wild swim could have a place in your self-care regimen. “There is emerging evidence around regular sauna use and regular cold water swimming,” says Macciochi. “ These work on various levels to support your immune system and are also a form of self-care and stress relief, they also can be a source of social wellbeing which we also know is good for our immune system.”