With over 70% of the immune system residing in the gut, it is key to keep this area in its best health. Colourful and nutrient-dense fruit and veg will support gut health and the microbiome. Aim to eat 30 different plants a week – a diverse range of foods like this will not only provide different nutrients each supporting different functions, but will encourage a diverse gut microbiome. Citrus fruits, squash and kiwis are all rich in vitamin C which stimulates the white blood cells key for fighting infections. Orange-coloured fruit and veg are rich in beta-carotene, a pre-cursor to vitamin A that maintains the mucosal linings in the respiratory and digestive tracts, which act as a first line of defence. 

Mushrooms contain beta-glucans, which have been shown to enhance immune function and increase the body’s natural defences. They are also a food which can absorb vitamin D, so leave them on the windowsill to soak up the sunshine before you consume them. Alternatively, a good mushroom supplement blend is Hifas da Terra Mico Five.

Oily fish such as sardines, mackerel, anchovies and salmon are rich in omega-3 polyunsaturated fatty acids, which help with the structure of our cells. They are key for regulating immune cell function as well as maintaining the integrity of our gut lining. A supplement like Bare Biology Rise and Shine combines Omega-3 and Vitamin D in one. 

Fermented foods such as kefir, sauerkraut and miso contain probiotic foods to help maintain a healthy gut, which is, of course, crucial for a strong immune system. Vadasz does a good unpasteurised sauerkraut.

Zinc-rich foods like red meat, oysters and pumpkin seeds enable the immune system to function optimally. Zinc is critical for the development of immune cells as well as being a key anti-inflammatory nutrient. Maintaining adequate intake will help to keep the immune system functioning – Biocare Immune Intensive combines zinc and other key vitamins and minerals for an overall support. 

Green leafy vegetables such as cavolo nero, brussels sprouts and cabbage are rich in B vitamins, as well as vitamins C and K, antioxidants and iron to support a healthy immune system. They are also a good source of fibre to aid detoxification.

Vitamin D is key to regulating the immune system, but current figures show one in five UK adults are deficient in it. Up to 90% of vitamin D is synthesised from the sunshine, but from October to April the sun in the UK is too weak for our skin to synthesise its vitamin D. That’s why the NHS recommends supplementing with 10mcg per day during these months. To test your own vitamin D levels, book an appointment with your GP – or the likes of BetterYou and MediChecks sell at-home kits to test yourself and can advise on supplementation.

Sleep is essential for general recovery and to strengthen the immune system. Aim for 7 to 9 hours sleep a night, keeping consistent sleep and wake times, and ensuring you get natural daylight first thing in the morning to help set the circadian rhythm. To aid restorative sleep, you could try adding Epsom salts to a bath. 

Dehydration hinders the body’s ability to detoxify and remove pathogens. To stay hydrated as the temperature drops, move to herbal teas, broths and warm drinks. Electrolytes are a useful addition to ensure you are replenishing lost minerals. Watch out for added sugars and sweeteners in some products and go for cleaner options like Elete Water.

Chronic stress can weaken the immune system. The lead up to Christmas can be busy, but try and take a bit of time out for yourself. Moderate exercise, walking and stretching can all help keep your immune system in good shape, improving circulation, aiding the lymphatic system and flushing out toxins.