Vitamin C is a water-soluble vitamin that you can only get through your diet. It's good for your skin, bones and blood vessels. Vitamin C also supports your immune system, protecting you from infections — like the common cold.

What is vitamin C?

Vitamin C, also known as ascorbic acid, is a water-soluble vitamin — a type of nutrient. Your body can’t make vitamin C so you must get it from your diet. You also can’t store vitamin C so you must continually get enough from your diet.

What does vitamin C do?

Vitamin C has many important functions in your body. Firstly, vitamin C is needed to produce a structural protein called collagen. Collagen is a type of protein that makes up an essential part of connective tissue — found in your skin, blood vessels, ligaments, bones, cartilage, and so on. And because of this, vitamin C is important for proper wound healing.

Vitamin C is also a powerful antioxidant, which helps protect your cells against damage from oxidative stress. Oxidative stress has been linked to chronic diseases like cancer and heart disease, so a high intake of antioxidants might help protect against these. Vitamin C might also help regenerate other antioxidants in your body, like vitamin E.

Vitamin C has also been shown to build up in immune cells called phagocytes, possibly enhancing their function. These are cells that ingest and destroy something that’s harmful, like bacteria and viruses.

Vitamin C also helps increase the absorption of calcium and non-heme iron (the type of iron in plant foods) in your body. 

How much vitamin C do you need?

The recommended amount of vitamin C is 40 mg a day for adults aged 19-64 years — equivalent to about an orange a day.

Food source of vitamin C — tomatoes

What foods contain vitamin C?

Good sources of vitamin C include:

  • kiwis — particularly gold kiwifruit
  • citrus fruits — like oranges, lemons, and satsumas
  • dark leafy greens — like spinach and cabbage
  • peppers
  • broccoli
  • tomatoes
  • potatoes

What can cause vitamin C deficiency?

Not having enough vitamin C as part of your diet is the main cause of low vitamin C levels — as your body can't make it. But a deficiency is quite uncommon. You might develop a mild deficiency if you follow a poor or very restricted diet.

What are the symptoms of vitamin C deficiency?

Symptoms of low levels of vitamin C include:

  • fatigue (low energy and motivation)
  • muscle and joint aches
  • bleeding gums

Vitamin C deficiency has also been linked to a weakened immune system, increasing your susceptibility to infections. 

Extreme cases of vitamin C deficiency is called scurvy. 

How to improve vitamin C levels

A balanced and varied diet should provide you with all the vitamin C you need. 

If you do take a vitamin C supplement, don't take too much as this could be harmful. Less than 1,000 mg of vitamin C supplements a day is unlikely to cause any harm. If you take more than this a day, it can cause stomach pain, diarrhoea, and flatulence. It’s always a good idea to speak to your pharmacist or GP before starting any supplement.

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Hemilä, H. (2017). Vitamin C and infections. Nutrients, 9(4), 339.

National Institute of Health (2020). Office of dietary supplements. Vitamin C: Fact sheet for health professionals. Retrieved 17 March 2020 from

National Health Services (2017). Vitamins and minerals: Vitamin C. Retrieved 17 March 2020 from