Vitamin A (also called axeroftol or retinol), has long been known for its essential role on the organ of sight, especially because it is necessary for the formation of the visual pigments of the retina, which allow the adaptation of vision when light decreases.
It also has many other important and essential roles as a factor in the growth and renewal of mucous membranes and skin cells, intervening in the body’s resistance to infection, and in the formation of certain hormones.
Unlike other vitamins such as vitamin B1, our body has quite substantial reserves of vitamin A, especially at the level of the liver, which normally has sufficient quantities to cover requirements for several months.
The importance of these reserves explains why, for example, vitamin A poisoning can occur if excessive amounts are taken in.
What is vitamin A?
Vitamin A is a vitamin popularly known as retinol, although it is also less commonly known as antixerophthalmic. It is characterized by being a fat-soluble vitamin, which means that it is a nutrient that is not solubilized in water, but it is in fat.
In other words, vitamin A is an essential nutrient capable of being stored in the fatty tissues of our body, above all in the liver and in the adipose tissue, so that an excess in its consumption can cause problems of toxicity, since its elimination by our organism tends to be more difficult.
In fact, vitamin A toxicity can cause skin, bone, visual and teratogenic disorders (in pregnancy it can cause fetal malformations).
As we will see below, there are different types of vitamin A, there are other molecules known as carotenoids, which work as provitamin A, when transformed into it in the liver and intestine (the most abundant is β-carotene or beta-carotene).
Do you know that there are two types of vitamin A?
There are two types of vitamin A depending on their origin:
Preformed vitamin A: we find it in foods of animal origin and derivatives, such as beef, poultry, fish and dairy products.
Provitamin A: we find it in vegetables, fruits and other foods and products of vegetable origin.
Functions of Vitamin A. What is it for?
It helps in the formation and maintenance of teeth, white tissues, bones, mucous membranes and skin.
Promotes good vision, especially in dim light. In addition, it produces the pigments in the eye’s retina.
It intervenes and participates in reproduction processes.
It participates in the natural immunity of our organism.
It helps the embryo to develop normally during pregnancy.
Advisable during breastfeeding.
Recommended Daily Amounts of Vitamin A
Age
Men (ug/day)
Women (ug/day)
0-12 months
350
350
1-6 years
400
400
7-10 years
500
500
+ 11 years
600
600
+ 15 years
700
700
Pregnancy
700
Breastfeeding
950
The best way to get the recommended daily requirement of vitamin A is to eat a complete and varied diet, rich in fruits, vegetables, legumes, whole grains, meat and fish.
It is important to note that the amount of each vitamin, like vitamin A, that each person needs depends on age and sex, as well as other factors, such as pregnancy, breastfeeding or the individual’s own health status.
Consequences of vitamin A deficiency
Although vitamin A deficiency is difficult to produce as it is found in a wide variety of foods, it is possible that it will appear.
When the deficiency in vitamin A is mild or marginal, the person may suffer some weakening of the immune system, which will lead to a greater susceptibility to infections, especially in the epithelials of the respiratory tract, or to skin problems.
When the deficiency is more severe, the person may notice a loss of vision due to various physical changes in the eye, especially in both dim light and nighttime situations. If the deficiency is maintained, it could eventually lead to blindness.
Therefore, the best way to provide vitamin A to our body is by adopting a balanced and complete diet, but without exceeding it, since an excess can produce hypervitaminosis, and water or chronic intoxication.
Food Sources of Vitamin A
Foods rich in vitamin A or retinol
Food
Vitamin A content
(ug/100 gr.)
Halibut liver oil
900.000
Lamb’s liver
19.900
Cod liver oil
18.000
Margarine
800
Butter
985
Cheddar cheese
363
Eggs
190
Pork kidney
160
Milk
56
Mackerel
45
They fear
10
Sardines
7
In addition to the foods listed above, we can also find vitamin A in fruits such as apricots, mangoes, melons and peaches, or in vegetables such as pumpkin. Also in legumes such as peas.
Foods rich in β-carotene
Foods such as green vegetables stand out above all. Carrots, spinach, cabbage, sweet potatoes, lettuce and broccoli also stand out.
Food
Content on β-carotene
(ppm)
Spinach
690 ppm
Carrot
673 ppm
Barley
659 ppm
Watercress
560 ppm
Spirulina
478 ppm
Chives
475 ppm
Pepper
465 ppm
Beet
438 ppm
Peanut
360 ppm
Parsley
267 ppm
Beans
245 ppm
Endive, endive
241 ppm