The Nutrition Information Centre of the
University of Stellenbosch (NICUS)
Nutrients
Vitamins: Vitamin C
What is it?
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin, which is essential for normal functioning of the body. Unlike most mammals, humans do not have the ability to make their own vitamin C and, therefore, must obtain it through their diet.
Functions - what does it do?
Collagen. Vitamin C is required for the production of collagen, an important structural component of blood vessels, tendons, ligaments, and bone. Deficiency, therefore, leads to poor healing of wounds, fractures, pinpoint bleeding, and bleeding gums.
Antioxidant. Vitamin C is also a highly effective antioxidant. Antioxidants such as vitamin C act to protect your cells against the effects of free radicals, which are potentially damaging compounds produced as by-products of normal metabolism, as well as through exposure to toxins and pollutants (e.g. smoking). Free radicals can cause cell damage that may contribute to the development of cardiovascular disease and cancers, and other diseases.
Vitamin C may also be able to reactivate other antioxidants such as vitamin E so that it can be resused.
Enhanced iron absorption. Vitamin C enhances iron absorption from non-haeme sources, which is found primarily in fruits, vegetables, dried beans, nuts and grain products. Therefore, increasing vitamin C-rich foods can be beneficial to those with poor iron stores.
Immune system. Vitamin C is vital for the fucntion of the immune system and promotes resistance to infection.
Requirements - How much do we need?
| Recommended Dietary Allowance* (mg/day) |
Life-Stage (years) | Males | Females |
0 - 0.5 | 40# | 40# |
0 - 0.5 (0 - 6 months) | 50# | 50# |
0.5 - 1 (7 - 12 months) | 15 | 15 |
4 - 8 | 25 | 25 |
9 - 13 | 45 | 45 |
14 - 18 | 75 | 65 |
Ages 19+ | 90 | 90 |
Life-Stage (years) | Pregnancy | Lactation |
18 and younger | 80 | 115 |
19 - 30 | 85 | 120 |
Ages 31 - 50 | 85 | 120 |
*The Recommended Dietary Allowance (RDA) is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals in each life-stage and gender group. #Adequate Intakes (AI) are used as no RDA is established. The AI is a recommended daily intake level based on observed or experimentally determined approximations of nutrient intake by a group of healthy people who are assumed to be maintaining an adequate nutritional state.
|
Sources - Where is it found?
Food Groups | Food Sources | Nutrient Density | High | Medium | Low |
|
Fruit | Citrus fruit,Cantaloupe, Guava, Pineapple, Strawberries |
Vegetables | Tomatoes, Potatoes, Cauliflower, Green vegetables |
Bread, cereals, rice and pasta | Some fortified breakfast cereals |
Meat, poultry, fish, dry beans, eggs, and nuts | |
Milk, yoghurt and cheese | |
Fats, oils, and sweets | |
Vitamin C is very easily lost in processing and cooking, because it is highly soluble (mixable) and is often discarded in cooking water. It is easliy destroyed by air, especially in the presence of heat and an alkaline solution.
Deficiency - When you have too little
Scurvy. Severe deficiency of vitamin C causes scurvy. Symptoms of scurvy include bleeding and bruising easily, hair and tooth loss, joint pain and swelling. These symptoms are due to the loss of the cementing action of collagen resulting in weakening of blood vessels, connective tissue, and bone.
Toxicity - When you have too much
High doses of vitamin C can lead to gastrointestinal disturbances including diarrhoea, and iron toxicity, caused by iron overabsorption.
| Upper Limit+ (mg/day) |
Life-Stage (years) | Males | Females |
0 - 0.5 (0 - 6 months) | ND | ND |
0.5 - 1 (7 - 12 months) | ND | ND |
1 - 3 | 400 | 400 |
4 - 8 | 650 | 650 |
9 - 13 | 1200 | 1200 |
14 - 18 | 1800 | 1800 |
Ages 19+ | 2000 | 2000 |
Life-Stage (years) | Pregnancy | Lactation |
18 and younger | 1800 | 1800 |
19 - 30 | 2000 | 2000 |
Ages 31 - 50 | 2000 | 2000 |
+Upper Limits (UL) = The maximum level of daily nutrient intake that is likely to pose no risk of adverse effects. Unless otherwise specified, the UL represents total intake from food, water, and supplements. ND = Not determinable due to lack of data of adverse effects in this age group and concern with regard to lack of ability to handle excess amounts. Source of intake should be from food only to prevent high levels of intake. |