With flu season and COVID-19 unfortunately on the rise again we need to find ways that we can support our immune system to help us fight off any nasty infections. We’ve all been in a situation where we feel a cold coming on and so we start to increase our fruit and veg intake, take some vitamin C tablets, or drink a big glass of orange juice. But, how much can our diets and nutrition actually impact the way our immune system functions?
The link between nutrition and immunity
Recent research has shown that the functioning of our immune system can be affected by the food we eat (1), with some studies even suggesting that diet and nutrition are some of the most important external factors that play a role in our immune response to disease (2). During times of infection or illness our body’s immune system works quickly and efficiently to help fight it and to make us feel better. Without certain nutrients, particularly those known as micronutrients (i.e. vitamins and minerals), the body would be unable to do this. Below are some important nutrients which help to support immune function and some examples of foods in which they are found (3).
Vitamin A: anti-inflammatory
- Animal products – cheese, eggs, oily fish, liver, milk and yoghurt
- Plant products – yellow, red and green veg (spinach, carrots, sweet potato, peppers) and yellow fruits (mango, apricots)
Vitamin C: encourages the production of white blood cells which are important in getting rid of infections
- Citrus fruits such as oranges, peppers, strawberries, blackcurrants, broccoli, brussels sprouts
Vitamin D: decreases susceptibility to infections
- Oily fish such as salmon and mackerel, red meat, liver, egg yolks, fortified foods
- The body creates Vitamin D from sunlight and so in the winter (October to March), when sunlight exposure is reduced, it is advised to take a Vitamin D supplement (10 micrograms or 400 IU)
Copper: helps improve immune response to infections
- Nuts, shellfish, offal
Folate: helps maintain white blood cell function
- Broccoli, brussels sprouts, leafy green veg, peas, chickpeas and kidney beans, liver, fortified breakfast cereals
Iron: encourages the production of white blood cells
- Animal products – liver, red meat
- Plant sources – beans such as kidney beans, edamame beans and chickpeas, nuts, dried fruits, fortified breakfast cereals
Selenium: reduces susceptibility to infection and disease
- Brazil nuts, fish, meat, eggs
Zinc: helps maintain white blood cell function
- Meat, shellfish, dairy foods such as cheese, bread, cereal products
Immunity and gut health
Having a healthy gut microbiome is also super important when it comes to our immune function as almost 70% of our immune system can be found within our gut (4)!! Here are some top tips to keep your gut happy and healthy to help support your immune system:
- Aim for the recommended 30g of fibre per day
- High fibre foods include, fruit and veg, wholegrains, nuts, and seeds
- Eat foods which are high in polyphenols such as fruits, veg, and dark chocolate
- Include probiotics or fermented foods such as yoghurt, kefir, sauerkraut, and kimchi
Although nutrition is important, here are some other ways that you can help to boost your immune system (5)
- Exercise regularly – even just a walk or some gentle yoga
- Get adequate sleep
- Keep stress to a minimum
- Maintain good personal hygiene
- Frequently wash your hands
- Drink alcohol in moderation
- Keep up to date with all the current vaccines
So, in conclusion the food we eat can have an impact on our immunity. Like most things in nutrition, eating a balanced and varied diet will help to benefit our immune systems. Issues arise when important nutrients, like the ones mentioned above, are not consumed and this means that our immune systems cannot function adequately. This leads us to having an increased susceptibility to infections and disease.
It is important to note that we cannot actually ‘boost’ the activity and function of our immune systems, it is more that we can supporthealthy immune function by consuming the right foods, such as vitamins and minerals.
Contribution by Registered Associate Nutritionist, Ellie Morris
References
- Venter C, Eyerich S, Sarin T, Klatt KC. Nutrition and the Immune System: A Complicated Tango. Nutrients. 2020; 12(3):818. https://doi.org/10.3390/nu12030818
- Barrea L, Muscogiuri G, Frias-Toral E, Laudisio D, Pugliese G, Castellucci B, Garcia-Velasquez E, Savastano S, Colao A. Nutrition and immune system: from the Mediterranean diet to dietary supplementary through the microbiota. Critical Reviews in Food Science and Nutrition. 2021; 61(18):3066-3090. https://doi.org/10.1080/10408398.2020.1792826
- https://www.nhs.uk/conditions/vitamins-and-minerals/
- Vighi G, Marcucci F, Sensi L, Di Cara G, Frati F. Allergy and the gastrointestinal system. Clinical and experimental immunology. 2008; 153 Suppl 1(Suppl 1):3–6. https://doi.org/10.1111/j.1365-2249.2008.03713.x
- https://www.health.harvard.edu/staying-healthy/how-to-boost-your-immune-system
