A member of the British Dietetic Association, Juliette Kellow has worked in the NHS and for the food industry, and is the former editor of magazines Slimming and Top Santé. She's also the former editorial...

This water-soluble vitamin has many functions in the body. It has a vital role to play in making collagen (a component of our blood vessels, bones, cartilage, gums, skin and teeth) so it’s important for helping wounds heal.

It’s also needed for our nervous system, helps give us a strong immune system and, as an antioxidant, it mops up cell-damaging free radicals.

Can I have too little or too much vitamin C?
It’s very rare in the UK to suffer with a deficiency of vitamin C, which results in scurvy, a condition that’s practically unheard of these days. Average daily intakes of vitamin C are around 80mg a day across most age groups, so the majority of us get plenty.

Large amounts (over 1,000mg a day) can cause side effects such as stomach pains, diarrhoea and flatulence, but you’re only likely to get this much through supplements. Symptoms usually disappear once you stop taking the supplements.

How much vitamin C do I need each day?
The Nutrient Reference Value (NRV) for vitamin C, which you’ll see on food labels, is 80mg a day. But there are more detailed guidelines in the UK for vitamin C needs at specific ages and stages in life, and these tend to be lower than the value used for labelling purposes.

how much vitamin c do we need

Where to find vitamin C in foods
The main sources are fruits and vegetables. Particularly rich sources include citrus fruits and their juices, strawberries, peppers, blackcurrants, green leafy veg and kiwis. Because in the UK we eat large amounts of them, potatoes are another main contributor of vitamin C.

food with vitamin c

Do vitamin C supplements stop colds?
Sadly not, unless you’re regularly doing endurance activities, such as running marathons, or are frequently exposed to very cold environments, where they may halve your risk of catching a cold.

However, there is evidence that vitamin C supplements of 200mg or more a day may help a little to reduce the length of time you experience symptoms. Studies have found that taking vitamin C may reduce the length of a cold by 8% in adults and 13% in children.

Vitamin C as a food preservative
The antioxidant effects of vitamin C mean it’s often used as an additive in food processing in a similar way to preservatives. Listed on food labels using its technical name, ascorbic acid, or E300, it helps to extend the shelf life of products and improve the taste and look of food.

For example, it’s used to stop cut fruits, pulps and juices discolouring (it’s why we squeeze vitamin C-rich lemon juice over sliced apples or avocados to stop them browning) and added to beers to improve their shelf life. It also helps to maintain the colour of meat and is used in baked products as a flour improver.

Regular vitamin C top-ups
Vitamin C can’t be stored in the body, so it needs to be included in our diet every day. It’s very sensitive to heat and water, both of which destroy it, so eating fruit and veg raw whenever you can will make full use of the vitamin C they contain. When cooking, keep them in large pieces, use the minimum amount of water and cook for a minimal amount of time (vegetables should be eaten al dente rather than mushy).

Related article: Why we need vitamin A