With only a few weeks to go before the clocks change, the nights are drawing in and the winter cold and flu season will soon be upon us. It’s time to make sure your diet is packed with the nutrients that will support your immune system through the winter months. Here are my top nutrients to help you fight off the germs.
Zinc affects the activity of the white blood cells in the immune system and has been shown to reduce the duration of colds.1 The best sources of this mineral are shellfish, meat, fish, nuts and seeds, especially pumpkin seeds.
Tip: add pumpkin seeds to your breakfast cereal and as a topping on soups. Swap sugary snacks for a handful of nuts and seeds.
This vitamin is vital for resistance to infections by supporting healthy mucous production by the mucous membranes lining the nose and lungs. Good sources of vitamin A include oily fish, cheese, eggs and liver (but note that you should not have liver or liver pate more than once a week to avoid potentially having too much vitamin A). We can also convert the beta-carotene found in vegetables such as butternut squash and sweet potatoes into vitamin A.
Tip: Click here for my recipe for butternut squash and kefir soup – butternut squash is ideal for increasing your resilience to winter bugs as it contains not only vitamin A, but also vitamin C and zinc.
Vitamin C is known to support the normal functioning of the immune system. While most studies have shown that this vitamin does not prevent colds, it can, like zinc, help to reduce the length of the infection.1 Good sources of vitamin C are dark green leafy vegetables, peppers, kiwi fruit and citrus fruit.
Tip: fresh fruit and salads provide a richer source of this vitamin compared to cooked plant foods as cooking reduces the amount of vitamin C.
Low levels of vitamin D are common in the UK – one study showed that almost 50% of adults aged 45 years have insufficient levels of this vitamin during the winter and spring.2 Recent evidence has shown that vitamin D reduces the risk of respiratory infections.3 In the UK, during the late autumn and winter we draw on our bodies’ vitamin D stores and can obtain some vitamin D from food, including oily fish, egg yolks, butter and liver.
Tip: It’s worth looking out for foods that are fortified with vitamin D, such as breakfast cereals and yoghurts.
Garlic has been used for thousands of years in various remedies. This culinary plant contains vitamin C, but it’s the sulphur-containing compounds, allyl sulphurs, that are of particular interest with regard to its therapeutic benefits. It has to be said that evidence for its effect on the immune system from modern studies is based mainly on its antibacterial and antiviral properties demonstrated in the laboratory, although one clinical study did show that daily garlic tablets reduced the frequency of colds.4
Food is just one way to support your immune system. Don’t forget:
• Make sure you get your flu jab if you’re in a vulnerable group
• Keep up your exercise over winter
• Try to get 8 hours of good quality sleep.
1. Nahas, R. and Balla, A. (2011) Complementary and alternative medicine for
prevention and treatment of the common cold. Canadian Family Physician, 57, 31-36.
2. Hypponen, E. & Power, C. (2007) Hypovitaminosis D in British adults at age 45y: nationwide cohort study of dietary and lifestyle predictors. American Journal of Clinical Nutrition , 85 (3), 860-868.
3. Martineau, A.R. (2017) Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. British Medical Journal, 356 (i6583), doi:10.1136/bmj.i6583.
4. Josling P. Preventing the common cold with a garlic supplement: a double‐blind, placebo‐controlled survey. Advances in Therapy 2001;18(4):189‐93.