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Updated on 22/03/2019

Vitamin C or ascorbic acid

Presentation, food sources and nutritional needs

Keywords : Nutrition, Vitamins

Vitamin C is involved in key functions in our body, such as defence against certain infections, or iron assimilation. Learn more about its role, the foods in which it is found, and the intake necessary for different population groups.

Definition, functions and roles

Vitamin C or ascorbic acid is involved in key functions in our body: defence against viral and bacterial infections, protection of the blood vessel walls, iron assimilation, antioxidant action (capture of free radicals), and healing. Vitamin C also promotes iron absorption.


Foods that are rich in vitamin C and sensitivity of the vitamin

Vitamin C is present in all plants but in variable quantities.

Vitamin C is the most fragile of all the vitamins: it is sensitive to air, heat and light. For example, at ambient temperature, food can lose half of its vitamin C content in 24 hours. It is therefore important to choose appropriate storage and cooking processes to reduce these losses.


Population reference intakes

The population reference intakes take account of vitamin C needs in the context of its dual role: antiscorbutic and antioxidant properties. Vitamin C needs are very high during certain illnesses (fracture, infections, cancer treatment) but also in certain lifestyles (intense physical activity, excessive alcohol consumption, smoking).

The population reference intakes (PRI) for adults were updated in 2016. They are 110 mg/day in both men and women.

The PRIs for other categories of the population are currently being re-assessed.


Risk of deficiency and excess intake

In people who are not deficient, the plasma vitamin C concentration is a good indicator of their vitamin status. Epidemiological studies (SU.VI.MAX in particular) have estimated optimal plasma vitamin C concentration at 60 µmol/L in young adults. This corresponds to the concentration which ensures the maximum antioxidant potential necessary for protection against risks of cardiovascular and neurodegenerative diseases, cancer and cataracts.

The disease most closely associated with vitamin C deficiency, is scurvy. It manifests itself through œdemas (tissue swelling due to excessive hydration) and haemorrhages, and may be fatal if it lasts for several months. Moderate deficiency, however, which is still common, can cause loss of appetite, weight loss and fatigue.

Vitamin C is eliminated in urine. However, excessive vitamin C can lead to stomach pains, diarrhoea and kidney stones.

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