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Vitamin C: Boosting your Immune System this Winter

Winter is very much here. There are so many colds and flus going around currently, and we still have very high Covid case numbers around. It seems like all of our immune systems could do with a boost.

There are so many vitamins and minerals that play a massive part in supporting our immune system. These include Vitamin A, C and D as well as Zinc. Other key foods that support the immune system are antioxidants, some herbs and spices, flavonoids, prebiotics, probiotics, high quality protein and an abundance of fruits and vegetables. Reducing highly processed foods and high sugar foods may support our immune systems as well. Let us delve into Vitamin C, one of the most important nutrients for our immune systems this Winter.

Vitamin C

Vitamin C is an essential vitamin in supporting the immune system, especially regarding upper respiratory system viruses.

Vitamin C is important for so many reasons, including:

  • Brain chemicals to send messages (neurotransmitters)

  • The Immune System and infection fighting. Cells called lymphocytes need Vitamin C to function properly.

  • Being a Strong Antioxidant. Antioxidants destroy compounds in our body that damages our cells. These molecules are called free radicals and they destroy cell membranes, the surrounding that protects a cell. Antioxidants destroy these free radicals to protect our cells.

  • To make Collagen. Collagen is used by our bodies to heal wounds, to strengthen bone, skin and blood vessels.

  • Helping to increase iron absorption. If you are low in iron, combining a Vitamin C food source with an iron source (beans, lentils) may help enhance your iron absorption.

Vitamin C is crucial for our good health, but the human body cannot make Vitamin C. This means we need to eat foods and drink beverages containing Vitamin C. Our bodies do not store Vitamin C for long periods either, so we need to include it in our diet on a regular basis.

Vitamin C in foods

Luckily, foods with Vitamin C are so readily available from your local supermarkets. There are so many sources of Vitamin C in fruits and vegetables.

The best sources of Vitamin C are:

  • Fruit: Guava, blackcurrants, cantaloupe / rock melon, kiwi fruit, lemons, lychees, papaya/paw paw, strawberries, oranges, mangoes, grapefruit

  • Vegetables: broccoli, kale, yellow or red pepper/capsicum, brussels sprouts

  • Herbs: Parsley, thyme

What affects the amount of Vitamin C in food?

There are a few things that may reduce the Vitamin C content in food:

  • Prolonged storage

  • Cooking food in water as Vitamin C is water Soluble. This means that if you cook a vegetable in water, the Vitamin C from the food item leaches out into the water.

  • Heat. If you cook a vegetable that has Vitamin C, the nutritional content may be lost as Vitamin C is sensitive to heat.

If increasing Vitamin C is your focus, aim for fresh raw fruits and vegetables to minimise the amount of Vitamin C being reduced through long storage, heat or cooking in water.

So how much Vitamin C do I need?

45mg per day is the Recommended Dietary Intake for adults. If you have more than 200mg per day, our bodies excrete it.

What does this look like in a day?

45mg is easily achieved in a day. 1 medium kiwi fruit or ½ cup of fresh strawberries, sliced and you’ve already gone over the 45mg recommendation per day!

Need help achieving your recommended Dietary intake of Vitamin C? Seeing a Dietitian always helps - OSCAR Care Group has a great team of Accredited Practising Dietitians, enquire here.

Orange you glad that Vitamin C is good for you?

We can keep things super simple to start with an orange:

¼ medium orange to meet about 40% of the Vitamin C recommendation per day

½ medium orange to meet about 80% of the Vitamin C recommendation per day

¾ medium orange to meet about 117% of the Vitamin C recommendation per day

1 medium orange to meet about 155% of the Vitamin C recommendation per day

If you simply aim for the recommendation of 5 serves of vegetables and 2 serves of fruit per day, you should be gaining a variety of important vitamins and minerals every day! Reach out to an Accredited Practising Dietitian for personalised support.


Kiarra Martindale, APD, BBiomedSc, MDiet, Lead Dietitian (APD) & Allied Health Manager for OSCAR Care Group

Kiarra Martindale is a Gut Health, IBS and FODMAP-trained Dietitian. She is a nationally recognised Accredited Practising Dietitian, Sports Dietitian, Anthropometrist, Nutritionist and Presenter.


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