Immune System Boost

As Winter draws near and the threat of Covid-19 lingers on it is an opportune time to think about what we can do to support our immune system. The health of our immune system is influenced by many factors including sleep, the amount of water we drink, stress and the food we eat.  


Our individual “Nutritional status has been accepted as a key factor in the outcome of a variety of different infectious diseases”  (1).  Diet and nutrition are critical for a strong immune system and there are many ways we can naturally and effectively boost our immune system to support it in resisting viruses such as the common flu and perhaps even Covid -19.  There has been much debate and interest in the value that Vitamin C, Vitmain D and other nutrients can offer in the fight against Covid -19. One thing is certain by having a strong immune system we can reduce the likelihood of getting sick and also improve our ability to overcome illness.


A starting point is looking at our diet and see if it is missing any of the key nutrients our immune system needs.  Top of the list to consider in order to boost your immune system are Zinc, Selenium, Vitamin C and Vitamin D.



Selenium is a powerful antioxidant and immune cell development and is available in red meat, poultry, eggs, Brazil nuts, brown rice to name a few. A serving of a few Brazil nuts a few times a week is generally sufficient to meet recommended daily amounts of Selenium Interestingly research has also shown that Selenium also supports a stronger vaccine response (3).


Zinc is an essential nutrient that our bodies are unable to produce or store so we must absorb it from food we eat or supplements. Although its functions within our body are numerous it is particularly critical for development and function of immune cells and also has anti-inflammatory benefits. (4)


Research has shown that zinc supplements can reduce the risk of infections and immune response in older adults and respiratory infections. (5, 6) Zinc is a must to build up our immune strength approaching winter.


Food Sources: Zinc

Zinc is available in red meat, shellfish (oysters, mussels, crabmeat), Chickpeas, Lentils, Seeds (pumpkin, sesame and hemp).

Vitamin C

Vitamin C is generally the first port of call to give a boost to immune system in particular for a winter cold. Vitamin C is an essential nutrient and supports your immune system in several ways:

Vitamin C is an antioxidant – it helps your body break down free radicals and can help reverse any damage caused by free radicals and reduce inflammation.

Although Vitamin C is unlikely to prevent you getting the flu or infections it is believed to help your body in fighting against an illness. This is due to its role in boosting the activity of phagocyte and lymphocyte immune cells. (2)

A well balanced varied diet with lots of fresh fruit and vegetable will ensure optimum levels are maintained. In winter this can be more challenging – here is a list of widely available Vitamin C rich foods and a recipe for a immune boosting smoothie and soups.

Food Sources: Vitamin C

Foods rich in Vitamin C include Blackcurrants, Strawberries, Kale, Broccoli, Brussel Sprouts, Lemons and Oranges.

Vitamin D - the sunshine vitamin.

Widely known as the sunshine vitamin as our bodies produce Vitamin D naturally during sun exposure. There is much discussion about Vitamin D due to its wide reaching benefits including mental health, immune system, bone health. Vitamin D is crucially important for the normal functioning of our immune system. Research has shown that Vitamin D can reduce likelihood of developing the flu. (7) and as an anti-inflammatory vitamin D can reduce the impact of inflammation in respiratory infections.(8)

For people living in Ireland, Vitamin D is often lacking due to our climate. It is advisable to get your Vitamin D levels checked with your GP before taking any supplements. 

Food Sources: Vitamin D

As well as through the Sun, Vitamin D is also available in in foods such as egg yolks, oily fish such as Salmon, Mackerel and Cod liver Oil.


In general a well-balanced wholefood diet will ensure you get all the nutrients you need. If you feel your immune system is under the weather give us a call and we can discuss in detail and recommend a immune boosting protocol to get you back to optimal levels. Call us to make an appointment on 086 8145559 or email:

Hope you enjoyed this feature!

Until next time

Tara and Venetia

Dun Laoghaire Nutrition Alliance


Recipes for Immune Boost:

Immune Boosting Pumpkin and Coconut Soup.



3 tbsp. Coconut oil

2 onions, peeled and roughly chopped

2 of garlic, peeled and finely chopped

800 g Pumpkin chopped

1 red pepper chopped in to small chunks.

2 tbsp. peeled and finely chopped root ginger

800 ml chicken or vegetable stock

400 ml tin of organic full fat coconut milk

Salt and freshly ground black pepper

Tip: if you like spicy food you could add some chili flakes.

2 tbsp. chopped coriander to serve


1.     Pour the coconut oil into a large saucepan on a medium heat and, when hot, add the onions and garlic.

2.     Cover with a lid and sweat for six to eight minutes or until softened but not browned.

3.     Stir in the pumpkin with the ginger and then cover again with the lid and cook, stirring occasionally, for 10 minutes or until the vegetables have softened.

4.     Add the red pepper and continue to cook for 5 minutes.

5.     Pour in the stock and coconut milk, bring to the boil, then reduce the heat and simmer for two to three minutes.

6.     Remove from the heat and liquidise the soup in a blender, or use a hand-held blender, then place back on the hob and heat through again.

7.     Season with salt, pepper and chili (if desired) and serve with a sprinkling of fresh coriand



Smoothie Recipes for Healthy Immune System 


Go Green



1 medium avocado

1 medium ripe banana

1 cup baby kale

1 1/2 cup milk of your choice (dairy, almond, oat)

2 tbsp almond butter



Place ingredients in blender and blitz until smooth.


Berry Sunshine Burst.




2 cups of mixed berries including blackcurrants and strawberries if possible.

1 cup vanilla Greek Yoghurt

1 cup milk of your choice

Juice from 1 orange

2 tbsp nut butter (almond or cashew)




Place ingredients in blender and blitz until smooth.





1. Calder P, Carr A, Gombart A, Eggersdorfer M. Optimal Nutritional Status for a Well-Functioning Immune System Is an Important Factor to Protect against Viral Infections. Nutrients. 2020;12(4):1181.


2. Hemilä H. Vitamin C and Infections. Nutrients. 2017;9(4):339.



3. Avery J, Hoffmann P. Selenium, Selenoproteins, and Immunity. Nutrients [Internet]. 2018 [cited 3 October 2020];10(9):1203. Available from:



4. Prasad A. Zinc in Human Health: Effect of Zinc on Immune Cells. Molecular Medicine [Internet]. 2008 [cited 3 October 2020];14(5-6):353-357. Available from:



5. Haase H, Rink L. The immune system and the impact of zinc during aging. Immunity & Ageing [Internet]. 2009 [cited 3 October 2020];6(1). Available from:


6. Martinez-Estevez N, Alvarez-Guevara A, Rodriguez-Martinez C. Effects of zinc supplementation in the prevention of respiratory tract infections and diarrheal disease in Colombian children: A 12-month randomised controlled trial. Allergologia et Immunopathologia [Internet]. 2016 [cited 3 October 2020];44(4):368-375. Available from:



7. Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. The American Journal of Clinical Nutrition [Internet]. 2010 [cited 3 October 2020];91(5):1255-1260. Available from:


8.Hughes D, Norton R. Vitamin D and respiratory health. Clinical & Experimental Immunology [Internet]. 2009 [cited 3 October 2020];158(1):20-25. Available from:


 9. Selenium [Internet]. The Nutrition Source. 2020 [cited 3 October 2020]. Available from: