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French Agency for Food, Environmental and Occupational Health & Safety

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Updated on 27/02/2017

Vitamins à la carte

The role of the various vitamins and their food sources

Keywords : Vitamins, Nutrition, Food composition

Vitamins are divided into two groups according to their ability to dissolve in water (hydrosoluble vitamins) or in fat (liposoluble vitamins). Below is a review of the role of water-soluble vitamins in the body and the foods that contain them.

  • Vitamin A

it is indispensable for proper vision, in particular at twilight. It also helps maintain the skin and mucous membranes in good condition. Furthermore it strengthens the immune system and acts on cell differentiation and growth.

Vitamin A is only found in animal products, and fish and animal liver oils contain large amounts.

This vitamin is sensitive to oxygen and light. To preserve it correctly, foods that are rich in Vitamin A should be stored for only short periods and =kept in air-tight packaging.


  • Beta-carotene

Beta-carotene is in fact a provitamin. It is a plant precursor of Vitamin A.

It also has antioxidant properties since it is capable of scavenging free radicals.


The B group of vitamins

The eight B vitamins are found in almost all food groups (meat, fish, eggs, dairy products, cereals, fruits and vegetables). They are involved in many different processes within the body.

  • Vitamin B1 (or thiamin)

Vitamin B1 acts on the transmission of nerve impulses. It also plays an essential role in the energy metabolism of carbohydrates. It is therefore important to ensure sufficient vitamin B1 intake with a high-carbohydrate diet.

It is particularly sensitive to high temperatures. Foods that are rich in vitamin B1 should thus be cooked moderately and eaten immediately after cooking.


  • Vitamin B2 (or riboflavin)

Vitamin B2 is involved in all of the biochemical reactions that produce energy from carbohydrates and fats. It is also involved in sight and helps keep skin and mucous membranes in good condition.

It is sensitive to light. To protect it, foods should simply be kept out of the light and only very fresh products should be purchased.


  • Vitamin B3 (or vitamin PP or Niacin)

Vitamin B3 is part of the make-up of enzyme systems which are essential for the metabolism of carbohydrates, fats and proteins. It thus helps cover the body's energy needs.

It also contributes to the functioning of the nervous system.


  • Vitamin B5 (or pantothenic acid)

Vitamin B5 is involved in the metabolism of carbohydrates, fats and amino acids. It thus promotes cellular activity in particular for skin, hair and mucous membranes.


  • Vitamin B6 (or Pyridoxine)

Vitamin B6 is involved in protein metabolism. It is thus important to ensure an adequate intake of vitamin B6 if a diet is rich in proteins. It also intervenes in the synthesis of neurotransmitters, the release of glucose from glycogen (the stored form of glucose) and in the formation of haemoglobin in red blood corpuscles.


  • Vitamin B8 (or biotin)

Vitamin B8 participates in many biochemical reactions at cell level, for the metabolism of carbohydrates, proteins or fats.


  • Vitamin B9 (or folates)

Vitamin B9 plays a key role in renewing all of the body’s cells: red and white blood corpuscles, cells of the skin, liver, intestines, nerve cells, etc. Consequently women of childbearing age should ensure that they have an adequate intake of this vitamin.

It is also involved in the synthesis of neuromediators which are indispensable for the healthy functioning of the brain and the nervous system in general.

Finally, vitamin B9 acts on red blood corpuscles and promotes the oxygenation of cells.

It is a particularly fragile vitamin as it is sensitive to air, light and heat. To preserve it, fresh foods should be stored as briefly as possible, and always out of the light. Likewise, to preserve vitamin B9, food should not be overcooked and should be eaten immediately after cooking.


  • Vitamin B12 (or cobalamin)

Vitamin B12 is necessary for the formation of red blood corpuscles: it is an anti-anaemic.

It is indispensable for the renewal of cells and consequently helps maintain the skin and nerve cells in good condition.


  • Vitamin C

Vitamin C plays many roles. In particular it stimulates the defence reactions of the body against infectious attack (bacterial or viral) and thus reinforces our immune systems. It is also involved in mechanisms by means of which the intestines absorb iron. It controls the formation of connective tissue (collagen) and the protein matrix of bone tissue.

Due to its antioxidant properties, it can scavenge free radicals and thus protect cells against their toxic effects.

It is found in fruits (citrus, soft fruit) and vegetables (bell peppers).

Note that vitamin C is very fragile. It is sensitive to oxygen and heat, and is soluble in water. To preserve it you should store fresh food for as brief a time as possible, limit soaking and cook it only a short time and in very little water.


  • Vitamin D

Vitamin D plays two essential roles. On the one hand it ensures optimum mineralisation of bones during growth and their renewal throughout the body's lifetime. On the other hand it modulates the intestinal absorption of calcium and contributes to the stability of calcium concentration in the blood and in tissues.

Part of our needs are covered by regular and moderate exposure of the skin to the sun. Vitamin D is also found in oily sea fish such as salmon, herring and sardines.

This vitamin is sensitive to oxygen and light. To preserve it, it is recommended that foods which are rich in vitamin D be stored for short periods only and out of the light. Furthermore food packaging should be airtight.


  • Vitamin E

Vitamin E has antioxidant properties. It acts in particular at the level of cell membranes and lipoproteins. Vitamin E is normally found in oilseed crops (olives, walnuts, rapeseed, etc), or in vegetable oils and their derivatives. This vitamin is sensitive to light. To preserve it, foods that are rich in vitamin E should be stored out of the light.


  • Vitamin K

Vitamin K is indispensable for blood clotting and promotes the fixation of calcium on the protein matrix of bone.

It is sensitive to oxygen and especially to light. To preserve it, foods that are rich in vitamin K should be stored only briefly and always kept out of the light.