If only there was one magical food that could fight off the winter germs! In reality, the key to winter wellness is a varied diet with an array of vitamins, minerals, and protein to help support your immunity. Our Swisse Dietitian is here to talk about foods that support the immune system.

Foods to boost immunity 

Supporting the immune system with foods can be achieved by consuming sufficient nutrients through a healthy and varied diet in order to boost the health and function immune cells ⁽¹⁾. It also gives the body the micronutrients it needs to activate the different stages of its immune response ⁽¹⁾. Here are some key foods for an immune system boost, that you can consider adding to your diet to help keep you fighting fit this winter.

1. Seafood

People are often hesitant about cooking seafood at home. However, as far as foods that boost the immune system go, it’s worth trying as seafood is packed with valuable nutrients that might help you get through winter a little healthier.

Seafood is a valuable source of protein, which helps with building immune system cells. Oily-types of fish, such as sardines, salmon and maceral, along with oysters, have higher levels of zinc, which supports immune system ⁽²⁾ function and wound healing.

Oily fish ⁽³⁾ also contains vitamin A and vitamin D, which support healthy functioning of the immune system. Not many foods contain vitamin D, we obtain most of it from exposing our skin to the sun.

2. Legumes

Legumes ⁽⁴⁾ are a beneficial food source for the gut, as they support the growth of good gut bacteria which in turn supports a healthy immune system. Legumes contain prebiotic fibre which is what your good gut bacteria likes to eat. Prebiotic fibre travels undigested through the digestive system to the large intestine where it is fermented by  bacteria. This fermentation produces short chain fatty acids and gases that are healthy for your gut and enter the blood stream to signal different parts of the immune system ⁽⁵⁾.

As well as being a food beneficial  for immune system health, legumes are also very versatile. You can add legumes such as chickpeas, kidney beans, lupins and lentils to casseroles, soups and curries. Black beans go well in stir frys and even in chocolate brownies!

3. Yoghurt

Thanks to your increased intake of fibre, your gut bacteria is well fed. Now, let’s look at how else we can enhance your gut bacteria colonies.

Eating foods containing 1 billion CFU (colony forming units) probiotics per gram or more will help nourish your good gut bacteria.

Consuming a variety of other foods, such as fermented teas (kombucha), fermented vegetables that are not pasteurised (e.g. sauerkraut found in the fridge section of the supermarket, rather than the shelf variety), miso (fermented soy beans), fermented yoghurt drinks (e.g. kefir or Filmjolk),  will provide you with a range of different beneficial bacteria. These immune-boosting foods might not contain high levels of bacteria themselves, however the variety of metabolites they produce during the fermentation process are beneficial for your gut and therefore your immune system ⁽⁶⁾.

4. Extra virgin olive oil (EVOO)

Foods that are rich in antioxidants are good for the immune system. We often think of fruits and vegetables when we think of antioxidants and while these are a major source of antioxidants, fresh high quality extra virgin olive oil also provides us with antioxidants⁽⁷⁾. Antioxidants help mop up free radicals, damage caused by oxidation in the body.

Extra virgin olive oil helps with the absorption of fat-soluble vitamins, such as vitamin E, which also provides antioxidant support. Pouring extra virgin olive oil on vegetables makes them taste nicer which means you will eat more of them, further boosting your vitamin and mineral intake!

5. Vitamin C-rich fruits

Last but not least, keep up your vitamin C levels by eating fruits and vegetables that are rich in this nutrient. Fruit is well known as being amongst one of the best foods for the immune system, so aim to consume at least two pieces of fruit each  day.

Which fruit is best for immunity?

Fruits that are best for immunity are citrus fruits (oranges, kiwi, lemon, grapefruit), and strawberries – which all have high vitamin C content ⁽⁸⁾.

Does lemon boost the immune system?

Lemons are an excellent source of vitamin c and therefore help support immune health⁽⁹⁾. Switching out your morning orange juice with a glass of lemon water will ensure you get the same vitamin boost with far less sugar and calories ⁽⁹⁾.

Finally, in winter we often spend more time indoors. A fun indoor winter activity is having a cook up with family and friends. It is a great way to bond and enjoy food together. It can also be a relaxing experience to sit and enjoy a long lunch, dinner or weekend breakfast with family and friends.

References:

1. Harvard School of Public Health. The Nutrition Source: Nutrition and Immunity. https://www.hsph.harvard.edu/nutritionsource/nutrition-and-immunity/ Accessed 29 July 2023.
2. Lin PH, Sermersheim M, Li H, Lee PHU, Steinberg SM, Ma J. Zinc in Wound Healing Modulation. Nutrients. 2017;10(1):16. Published 2017 Dec 24. doi:10.3390/nu10010016
3. https://www.heartfoundation.org.au/getmedia/873a7533-e4d1-43ea-9e6a-7a4f9a0c61af/190729_Nutrition_Position_Statement_-_Fish_and_Seafood.pdf
4. https://www.glnc.org.au/keep-your-immune-health-on-track-with-legumes/
5. Corrêa-Oliveira R, Fachi JL, Vieira A, Sato FT, Vinolo MA. Regulation of immune cell function by short-chain fatty acids. Clin Transl Immunology. 2016;5(4):e73. Published 2016 Apr 22. doi:10.1038/cti.2016.17
6. Bell V, Ferrão J, Pimentel L, Pintado M, Fernandes T. One Health, Fermented Foods, and Gut Microbiota. Foods. 2018;7(12):195. Published 2018 Dec 3. doi:10.3390/foods7120195
7. Rafehi H, Ververis K, Karagiannis TC. Mechanisms of action of phenolic compounds in olive. J Diet Suppl. 2012;9(2):96-109. doi:10.3109/19390211.2012.682644
8. Harvard School of Public Health. The Nutrition Source: Vitamin C. https://www.hsph.harvard.edu/nutritionsource/vitamin-c/ Accessed 29 July 2023.
9. Texas A&M University. The health benefits of lemon. https://vitalrecord.tamhsc.edu/health-benefits-of-lemon/ Published 18 August 2016.