As the days get colder and darker, winter often brings more coughs, colds, flu, and sickness bugs. We spend more time indoors and in closer contact with other people, while some viruses also spread more effectively in colder, drier conditions.
Although no single food or supplement can prevent winter illness, there are plenty of things we can do to support our immune system.
How can we make our immune systems more resilient before winter?
In the UK, sunlight isn’t strong enough for most of us to make enough vitamin D through our skin during autumn and winter. NHS guidance recommends that adults and children over four consider taking 10 micrograms of vitamin D each day during these months.
Other nutrients important for normal immune function include vitamins A, C and zinc. Colourful plant foods also provide antioxidants, which help protect cells from oxidative stress and support a healthy inflammatory response.
Rather than waiting until you already have a cold, focus on the foundations: balanced meals, hydration, regular movement, enough sleep and stress management. Listen to your body; if you feel run down, make more of an effort to get an earlier night and some extra recovery time. Rather than trying to reduce stress where it may not be in your control, finding suitable ways to counteract stress can help. For example, an app with relaxing music, a few minutes of deep, calm breathing, scheduling downtime with family. It sounds boring, and we’re all busy, but it can make a huge difference to your immune system.
What does gut health have to do with fighting off viruses?
The walls of the intestines are one of the body’s major barriers to the outside world. It contains a large network of immune tissue, known as gut-associated lymphoid tissue (GALT), which helps the body recognise harmful microorganisms while maintaining tolerance to food and beneficial gut bacteria. The traditional grandma’s remedy for illness - long-simmered chicken soup rich in the amino acid L-glutamine- helps to strengthen the intestinal lining barrier and is warm and comforting.
Our gut microbiome also communicates closely with the immune system. Beneficial gut microbes ferment fibre and produce compounds that help support normal immune balance. One of the best ways to support the microbiome is to eat a variety of fibre-rich plant foods. For people with IBS, some fibres can trigger symptoms, but there are still plenty of lower-FODMAP choices such as kiwi, oats, carrots, green beans, sourdough bread, nuts and seeds. Fermented foods such as live yoghurt, kefir and sauerkraut can also be useful if tolerated. People suffering with gut conditions may benefit from working with a registered Nutritional Therapist or Dietitian to improve their gut and immune resilience, where some specific, safe and suitable prebiotic or probiotic supplements may be beneficial.
Can we shorten the duration or severity of colds, flu and sickness bugs?
There is no reliable way to stop a viral infection once you have caught it, but nutrition can support recovery. Regular vitamin C intake may slightly reduce the duration of a cold. Good food sources include oranges, kiwi, strawberries, blackcurrants, peppers, kale, broccoli and Brussels sprouts. A whole orange may be better than orange juice for those with certain FODMAP intolerances. Check the Monash FODMAP app for portion sizes of fruit and vegetables. Vitamin D is found in oily fish such as salmon, mackerel, sardines and herring, as well as eggs, some mushrooms and fortified foods. Zinc-rich foods include meat, shellfish, eggs, pumpkin and sunflower seeds, cashews and lentils. Always consult a GP if supplementing, as high zinc doses can causes nausea/ vomiting and copper imbalances. Vegans or vegetarians may struggle to meet their vitamin D and zinc needs. Antioxidant-rich foods include brightly coloured fruit such as berries and vegetables, ginger, turmeric, green tea, herbs, nuts, dark chocolate and extra virgin olive oil.
Key takeaways
There is no single food, supplement or remedy that can guarantee you won’t catch a winter cold or sickness bug. Instead, focus on building resilience before winter arrives:
- Eat a colourful, Mediterranean-style, varied diet with enough protein and foods rich in vitamin C, vitamin D, zinc and antioxidants.
- Don’t forget the basics: stay hydrated and prioritise sleep, movement, calm and recovery.
- Look after your gut microbiome with a range of fibre-rich foods you tolerate.
- If you become unwell, keep things simple: fluids, rest and simple, nourishing foods you can tolerate. Batch cooking can be a great way to keep homemade meals ready in the freezer. With vomiting or diarrhoea, replacing fluids and electrolytes becomes especially important.
- Looking after your immune system isn’t about eating perfectly. It’s the small things you do consistently that matter most.
Written By Naomi Grieve, Registered Nutritional Therapist specialising in IBS and gut health.
