What is Vitamin C

The cold, dark days of winter are upon us. As we herd together on trains and buses and in schools and work places, colds spread easily. Over 20 million work days[1] are lost to minor infections like the common cold so is there anything we can do to prevent catching them?

The twice Nobel laureate Linus Pauling thought there was. In his book ‘Vitamin C and the common cold’ published in 1970, he promoted the idea that taking large doses of vitamin C could reduce the duration and severity of the common cold. However, his beliefs about the ability of vitamin C to prevent and cure colds has been called into question. So let’s find out more about vitamin C and the common cold.

What is Vitamin C?

Vitamin C, also known as ascorbic acid, is involved in making collagen required for the normal structure and function of skin, cartilage, bones and blood vessels (hence the bleeding gums seen in scurvy). It is an important nutrient for the healing process, Vitamin C also helps the body to absorb iron from food. Iron is a mineral necessary to ensure healthy growth in young children.

Vitamin C and scurvy

Vitamin C has a fascinating history. It was known even in the 18^th century that sailors on long voyages, deprived of eating fresh fruit and vegetables succumbed to a disease known as scurvy, where their gums bled and their hands and feet became swollen and painful. If the sailors were given oranges and lemons to eat their scurvy disappeared. It was later discovered that it was vitamin C in fruit and vegetables that cured and prevented scurvy.

Which foods are good sources of vitamin C?

Fresh fruits especially citrus fruits and berries; green vegetables, peppers and tomatoes are all sources of vitamin C. It is also found in potatoes (especially new potatoes).

How much vitamin C do we need?

Adults (over 19 years) need 40mg of vitamin C daily. Children and babies need about half that[2].

You should be able to get all the vitamin C you need from your daily diet for example, a kiwi fruit contains about 50mg; a large orange contains 70mg.

Vitamin C daily cannot be stored in the body and so it needs to be consumes daily. It is also heat sensitive and can be destroyed during prolonged cooking.

Is taking too much vitamin C harmful?

A daily dose of 2,000 mg or more can cause nausea, diarrhoea, abdominal pain, and it may interfere with tests for blood sugar. At doses above 400mg, vitamin C is excreted in the urine.

Can Vitamin C prevent or treat cold symptoms?

An extensive scientific review conducted in 2013[3] found that among extremely active people—such as marathon runners, skiers, and Army troops doing heavy exercise - taking 200 mg of vitamin C every day appeared to cut the risk of getting a cold in half. But for the general population, taking daily vitamin C did not reduce the risk of getting a cold. However, a regular daily dose of 200mg of vitamin C did slightly reduce the duration of cold symptoms in the general population.

Should you take a supplement?

It is always better to get vitamin C from food as you also get other important nutrients. If you eat five pieces of fresh fruit and vegetables a day you will get enough vitamin C in your diet to remain healthy. So rather than taking a pill at breakfast, eat a couple of kiwi fruit, or make a fruit shake and don’t forget those green vegetables at dinner time.

[1] www.ons.gov.uk

[2] British Nutrition Foundation

[3] Vitamin C for preventing and treating the common cold