Vitamin C, also known as ascorbic acid and ascorbate, is a vitamin found in various foods and sold as a dietary supplement. It is used to prevent and treat scurvy. Vitamin C is an essential nutrient involved in the repair of tissue and the enzymatic production of certain neurotransmitters. It is required for the functioning of several enzymes and is important for immune system function. It also functions as an antioxidant.
Evidence does not support its use for the prevention of the common cold. There is, however, some evidence that regular use may shorten the length of colds. It is unclear whether supplementation affects the risk of cancer, cardiovascular disease, or dementia. It may be taken by mouth or by injection
Foods containing vitamin C include citrus fruits, kiwifruit, guava, broccoli, Brussels sprouts, capsicum (bell peppers) and strawberries. Prolonged storage or cooking may reduce vitamin C content in foods.
Sources of Vitamin C
(mg / 100g)
|Yellow Capsicum (bell pepper)||183|
|Red Capsicum (bell pepper)||128|
(mg / 100g)
|Green Capsicum (bell pepper)||80|
|Loganberry, Redcurrant, Brussels sprouts||80|
|Passion fruit, Spinach||30|
(mg / 100g)
|Potato, Honeydew Melon||20|
|Apricot, Plum, Watermelon||10|
|Carrot, Apple, Asparagus||6|
Animal-sourced foods do not provide much vitamin C, and what there is, is largely destroyed by the heat of cooking. For example;
- Raw chicken liver contains 17.9 mg/100 g, but fried, the content is reduced to 2.7 mg/100 g.
- Chicken eggs contain no vitamin C, raw or cooked.
- Vitamin C is present in human breast milk at 5.0 mg/100 g and 6.1 mg/100 g in one tested sample of infant formula, but cow’s milk contains only 1.0 mg/ 100 g.
Vitamin C chemically decomposes under certain conditions, many of which may occur during the cooking of food. Vitamin C concentrations in various food substances decrease with time in proportion to the temperature at which they are stored. Cooking can reduce the vitamin C content of vegetables by around 60%, possibly due to increased enzymatic destruction. Longer cooking times may add to this effect.
Another cause of vitamin C loss from food is leaching, which transfers vitamin C to the cooking water, which is often decanted and not consumed. Broccoli may retain vitamin C during cooking or storage more than most vegetables.
Vitamin C dietary supplements are available as tablets, capsules, drink mix packets, in multi-vitamin/mineral formulations, in antioxidant formulations, and as crystalline powder. Vitamin C is also added to some fruit juices and juice drinks. Tablet and capsule content ranges from 25 mg to 1500 mg per serving. The most commonly used supplement compounds are ascorbic acid, sodium ascorbate and calcium ascorbate. Vitamin C molecules can also be bound to the fatty acid palmitate, creating ascorbyl palmitate, or else incorporated into liposomes.
In 2014, the Canadian Food Inspection Agency evaluated the effect of fortification of foods with ascorbate in the guidance document, Foods to Which Vitamins, Mineral Nutrients and Amino Acids May or Must be Added. Voluntary and mandatory fortification was described for various classes of foods. Among foods classified for mandatory fortification with vitamin C were fruit-flavored drinks, mixes, and concentrates, foods for a low-energy diet, meal replacement products, and evaporated milk.
Ascorbic acid and some of its salts and esters are common additives added to various foods, such as canned fruits, mostly to retard oxidation and enzymatic browning. The relevant European food additive E numbers are:
- E300 ascorbic acid (approved for use as a food additive in the EU, U.S. and Australia and New Zealand)
- E301 sodium ascorbate (approved for use as a food additive in the EU, U.S. and Australia and New Zealand)
- E302 calcium ascorbate (approved for use as a food additive in the EU, U.S. and Australia and New Zealand)
- E303 potassium ascorbate (approved in Australia and New Zealand, but not in U.S.)
- E304 fatty acid esters of ascorbic acid such as ascorbyl palmitate (approved for use as a food additive in the EU, U.S. and Australia and New Zealand