The immune system is what protects us from infection and informs the body’s response to injury. It is very complex and many different parts of the body are involved including the skin, bone marrow, lymphatic system and mucous membranes.
Many factors affect our immune function including age, gender, genetics, stress, smoking, exercise, vaccination and infection history. When we talk about nutrition related factors we can consider diet, obesity, nutrient status, alcohol intake and gut health as having an effect our immune function.
We talk about eating certain foods to boost our immune systems. In reality, our immune systems boost themselves in response to a perceived threat – like an infection and sometimes in overreaction – like in an autoimmune condition. There is no food or supplement that acts as a switch to boost it. So, a boosted immune system is not exactly what we are after.
We want to support and optimise the normal functioning of the immune system.
When our immune system is activated, and enters action mode in response to a threat, there is an increased demand for energy (calories) and some nutrients. This is provided by the food that we eat and the stores we already have in our bodies.
Many nutrients in food are involved in the functioning of the immune system including:
| Nutrient | Food Sources |
|---|---|
| Protein | Meat, fish, poultry, eggs, dairy, peas, beans, lentils, tofu and nuts. |
| Vitamin A | Liver, whole milk, cheese, butter and many reduced fat spreads (retinol). Carrots, dark green leafy vegetables and orange-coloured fruits, (carotenoids). |
| Folate | Green leafy vegetables, brown rice, peas, oranges, bananas and fortified breakfast cereals. |
| Vitamin B6 | Poultry, white fish, milk, eggs, whole grains, soya beans, peanuts and some vegetables. |
| Vitamin B12 | Meat, fish, milk, cheese, eggs, yeast extract and fortified breakfast cereals are all dietary sources. |
| Vitamin C | Fresh fruits especially citrus fruits and berries; green vegetables, peppers and tomatoes and potatoes. |
| Vitamin D | Sunlight is the main source. Food sources include oily fish, eggs, fortified cereals, meat and fat spreads. **10 µg per day supplementation is recommended in winter** |
| Vitamin E | Vegetable oils, nuts and seeds. |
| Copper | Shellfish, liver, kidney, nuts and wholegrain cereals. |
| Iron | Liver, red meat, pulses, nuts, eggs, dried fruits, poultry, fish, whole grains and dark green leafy vegetables are all sources of iron |
| Selenium | Brazil nuts, bread, fish, meat and eggs. |
| Zinc | Meat, milk, cheese, eggs, shellfish, wholegrain cereals, nuts and pulses. |
A healthy balanced diet including a variety of foods including those listed above is the best way to support our immune system from a dietary perspective. Irelands healthy eating guidelines and the food pyramid are helpful to guide healthy food choices. It is also important to look after gut health by including lots of fruits, vegetables, wholegrains and legumes to protect the gut flora.
It is important to remember that diet is only one of the controllable factors affecting immune function. Physical activity, sleep hygiene and stress management are the other vital factors it is important to manage in order to support a healthy immune system.
New Product Development
Covid-19 has led to many people learning more about the human immune system and trying to keep themselves healthy. Consumers are aware of the effects of the foods they eat on their health are looking to their diet for ways to support their immune systems.
Consumers now recognise Vitamin C, Vitamin D, Selenium and Zinc in particular as having a role to play in immune function. The development of new food products containing significant levels of these nutrients will appeal to the health conscious consumer, as will food products to improve sleep quality and stress management.
If you have an idea for an innovative new food product which might support immune function, get in touch to see how we at MET might be able to support your progress.
Sources and further information:
- Chandra, R.K., 2002. Nutrition and the immune system from birth to old age. European journal of clinical nutrition, 56(3), pp.S73-S76.
- Childs, C.E., Calder, P.C. and Miles, E.A., 2019. Diet and immune function.
- Food Safety Authority of Ireland (2020) Vitamin D Scientific Recommendations for Food-Based Dietary Guidelines for Older Adults in Ireland
- Food Safety Authority of Ireland (Healthy eating, food safety and food legislation A guide supporting the Healthy Ireland Food Pyramid https://www.fsai.ie/publications/healthy_eating_guidelines/
- https://www.fsai.ie/faq/coronavirus.html
- https://www.hse.ie/eng/about/who/healthwellbeing/our-priority-programmes/heal/healthy-eating-guidelines/
- https://www.hse.ie/eng/about/who/healthwellbeing/our-priority-programmes/heal/food-pyramid-images/food-pyramid-simple-version.pdf
- Iddir, M., Brito, A., Dingeo, G., Fernandez Del Campo, S.S., Samouda, H., La Frano, M.R. and Bohn, T., 2020. Strengthening the immune system and reducing inflammation and oxidative stress through diet and nutrition: considerations during the COVID-19 crisis. Nutrients, 12(6), p.1562.
- Maggini, S., Pierre, A. and Calder, P.C., 2018. Immune function and micronutrient requirements change over the life course. Nutrients, 10(10), p.1531.
- Nutrition and Immunity – Science At-A-Glance – KHNI (kerry.com)
- Venter, C., Eyerich, S., Sarin, T. and Klatt, K.C., 2020. Nutrition and the immune system: a complicated tango. Nutrients, 12(3), p.818.
- Vitamins and minerals – British Nutrition Foundation
- Vitamins and minerals – Vitamin D – HSE.ie
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