Vitamins A 

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Vitamin A plays an important role in vision, especially in terms of the eye's adaptation to darkness. It is also involved in bone growth, reproduction and regulation of the immune system.

It contributes to the health of the skin and mucous membranes (eyes, respiratory and urinary tract, intestines), which constitute our first line of defense against bacteria and viruses.

The benefits of Vitamin A

  • Vitamin A is essential for vision, involved in triggering nerve impulses to the optic nerves.
  • It is essential for growth, since it is involved in cell differentiation.
  • It also stimulates cell renewal and is, as such, important for the skin and all the mucous membranes.
  • It contributes to the functioning of the immune system.
  • Beta-carotene, for its part, has an antioxidant action: in synergy with other micro-nutrients (vitamins C and E, selenium, etc.), it helps protect the organism from premature aging1.

Vitamin A or axerophtol is a fat soluble vitamin.

It is in its alcoholic or retinol (vitamin A1) form that vitamin A is transported in plasma, cerebrospinal fluid, eye fluids and urine, associated with prealbumin.

Retinol is one of the three available forms of vitamin A, along with retinal and retinoic acid .

The body is not able to synthesize this vitamin naturally, it is therefore necessary for it to draw this source in the food.

Be careful, however, vitamin A is teratogenic, and therefore contraindicated in pregnant women.

Vitamin A (beta-carotene) in the diet

Vitamin A is supplied to us in the form of carotene or provitamin A via :

  • Milk
  • Raw dairy products
  • Liver
  • Carrots
  • Spinach
  • Fish oils
  • Plants
  • Butter
  • The egg yolk
  • Orange and yellow vegetables

Good to know: Vitamin A or retinol and beta-carotene are not very sensitive to cooking. They can, on the other hand, be degraded by oxidation, hence the advantage of keeping food in a cool place, away from air and light.

How to choose the right vitamin A food supplement in pharmacies?

The recommended nutritional intake is 800 micrograms per day for men, and 600 micrograms per day for women. A balanced diet covers vitamin A requirements.

The daily requirement for vitamin A is expressed in retinol equivalents or in international units. They change according to age and sex:

  • Up to 3 years: 300µg.

  • From 4 to 9 years old: between 450µg and 600µg

  • From 10 to 15 years old: between 550µg and 700µg

  • From 16 to 19 years old: between 600µg and 900µg

  • In adulthood: between 800µg and 900µg for men, between 600µg and 700µg for women

  • For pregnant women: between 700µg and 800µg

  • During breastfeeding: between 1.200µg and 1.300µg

Vitamin A comes in the form of tablets, soft capsules, oily solutions or products to be applied to the skin.

The doses of vitamins A are expressed in micrograms of retinol, in retinol equivalents (RE) or in international units (IU):
1 µg of retinol = 1 ER = 3.3 IU.

In 2012, the European health authorities (EFSA, European Food Safety Authority and the European Commission) estimated that food supplements containing vitamin A can contribute to the actions mentioned above if and only if these products contain at least 120 micrograms of vitamin A (retinol) per 100 g , 100 ml or per package if the product contains only one serving.

Food supplements provide an average of 1,500 micrograms per day. This amount corresponds to the maximum dose that a pregnant woman can ingest each day.

Decision of the European health authorities on vitamin A

In 2012, the European health authorities (EFSA, European Food Safety Authority and the European Commission) commented on certain health claims for foods and food supplements containing vitamin A (retinol). After examining the scientific data, they considered that these products can claim to contribute:

normal energy metabolism,
the maintenance of normal skin and mucous membranes,
to normal vision,
the normal functioning of the immune system,
cellular specialization,
normal iron metabolism,
if and only if these products contain at least 120 micrograms of vitamin A (retinol) per 100 g, 100 ml or per package if the product contains only one serving.

Symptoms of vitamin A deficiency

Vitamin A deficiency can be caused by poor dietary intake, malabsorption, or increased use or excretion due to common illnesses.

Vitamin A deficiency causes keratinizing metaplasia of the epithelia (production of tissue different from that usually made by the lining tissues, and impregnated with keratin), which can cause:

  • Conjunctivitis
  • Keratomalacia (softening of the cornea)
  • Night blindness (significant decrease in vision in low light)
  • Dry and rough skin
  • Growth retardation
  • Dry and brittle hair
  • Night blindness
  • Eye damage

In underdeveloped countries, vitamin A deficiency is the leading cause of blindness.

On the other hand, hypervitaminosis in vitamin A can cause:

  • Headaches
  • Peeling of the skin
  • Bone thickening
  • Hepato-splenomegaly
  • Ease of fracture, especially of the neck of the femur

You will understand, vitamin A promotes blood circulation and visual acuity. It prevents or reduces infections, oxidation, acne, hair loss, insomnia, weight loss and is used in particular as a supplement in many cancers. This vitamin is used in the formation of rhodopsin, which is a pigment involved in the twilight vision synthesizing glycoproteins.

The carotenoid is a precursor of vitamin A, indicated in the protection of the immune system whose plant sources are carrot, apricot, peach, peppers, spinach, lettuce, tomato, sweet potato , broccoli, squash, apricot, and especially spirulina Arthrospira platensis.

Precautions for use with vitamin A for pregnant women and smokers

Smokers should not take vitamin A or beta carotene supplements : smokers who take vitamin A supplements may be associated with an increased risk of lung cancer.

During pregnancy, too much vitamin A can cause fetal malformations. For this reason, pregnant women should avoid enriching their diet with vitamin A and carotenoids; they must be satisfied with those contained in their food. Same precaution for breastfeeding women.

For more information, do not hesitate to ask your pharmacist for advice.

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