Vitamin A - retinol
English: vitamina a acid
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Occurrence and structure of vitamin A.
Beta-carotene, the precursor to vitamin A, can be split into two retinal molecules, which consist of four isoprene units and a simple ring system.
Vitamin A is supplied through food and is particularly found in animal food sources. The liver contains a particularly large amount of vitamin A, as the fat-soluble vitamin is stored in this organ. Other sources are milk and dairy products such as butter, eggs (especially egg yolks) as well as fish. The need can also be covered by a vegetarian or vegan diet.
The so-called provitamin A (β-carotene), which the body can convert into vitamin A. Provitamin A is particularly found in carrots. Other plant-based foods high in provitamin A are apricots, kale, spinach and pumpkin. The advantage of provitamin A is that the body only converts it into vitamin A when it is needed, so there is no risk of oversupply. However, an oversupply of animal foods is also rather rare.
And once again briefly summarizing the occurrence of vitamin A:
- vegetable (Carrots, oranges, spinach, brcolli, kale)
- animal (Liver products, fish, egg yolks, milk products)
function
Retinal is essential for that Visual process. Here it is part of the receptor complex that is sensitive to light. Incidence of light changes the structure of the retinal, which leads to the activation of a G protein. Ultimately, this chain of reactions results in the light being perceived as such.
From retinal can through transformations Retinol and Retinoic acid arise. The former protects epithelia (inner and outer body surfaces), The latter is involved in gene expression and therefore has an influence on development and growth.
Vitamin A deficiency
The first symptoms are usually night blindness. If it is more pronounced, the Cornea (Cornea, contributes most to the refraction of light and thus to vision). This is the number one cause of child blindness in underdeveloped countries!
Other symptoms of a vitamin A deficiency include cornification of the mucous membranes.
Vitamin A can also have too much intake. The so-called hypervitaminosis (over / too much) develops. Signs of this are dizziness, vomiting, headache and - if it persists - hair loss and skin dehydration.
Read more about: Vitamin deficiency.
Consequences for the skin from vitamin A deficiency
Vitamin A is important for normal skin function. Accordingly, a deficiency has a variety of effects on our largest organ, which, however, on their own are unspecific.This means that other causes are also possible and that the overall picture must always be considered.
One of the possible consequences of a vitamin A deficiency is dryness of the skin due to reduced sweat and sebum production. There is also increased wrinkling and a decrease in skin elasticity (see also: Dry skin - causes and care tips). Brittle nails and hair loss can also result.
In addition to dry mucous membranes, a lack of vitamin A also increases the risk of cancer. In addition to a dry mouth, reduced saliva production also results in an increased susceptibility to inflammation of the teeth and gums.
Consequences for the eyes of vitamin A deficiency
Since vitamin A is particularly important for the eyes and our sense of sight, a deficiency is often the quickest to show. Typically there is what is known as night blindness. This means that you can see much worse in the dark than before, or compared to healthy people without a lack of vitamin A. The cause is disturbed light-dark vision. In addition, visual acuity decreases. So you see more blurred and you can recognize faces more poorly and have problems reading.
In addition, the lacrimal glands and the conjunctiva dry out, resulting in dry, itchy eyes. In addition, yellow and keratinized spots can form. Ulcers can also form on the cornea. If a vitamin A deficiency is not compensated for, it can ultimately lead to blindness.
Read more on the topic: Dry eyes - what are the causes, what helps?
Hair loss due to vitamin A deficiency
Vitamin A deficiency is one of many possible causes of hair loss. If symptoms of a vitamin A deficiency are present in the eyes and skin at the same time, the suspicion is reinforced. However, only a blood test and the professional assessment of a doctor can provide evidence. If only hair loss is noticed, a vitamin A deficiency is unlikely to be the cause.
A doctor can also clarify what is causing the hair loss. It is a widespread condition, especially among men but also among many older women. The cause are mostly hormonal problems. Under no circumstances should you attempt your own therapy with vitamin A preparations in the case of hair loss. If there is no deficiency, there is a risk of oversupply with dangerous consequences for the liver, for example.
Read more on the topic: Hair loss
Anti-acne remedies containing vitamin A
Medicines containing vitamins are very effective drugs for treating acne. The sebum glands of the skin are severely restricted in their function by therapy, which usually lasts for several months.
The skin is less oily and the pimples will decrease over time. Due to the large number of possible side effects, treatment should only be given if other measures are futile, the patient is under great strain and the patient understands and accepts the risks. This is especially true if the drug is to be used as an oral tablet.
In addition to minor adverse effects such as increased sensitivity to glare, in some cases psychological changes can even lead to depression. Less effective, but also with fewer side effects, can be treated with creams containing vitamin A for acne.
Often they are also used for maintenance therapy. That is, if the acne is treated with tablets, for example, and you want to prevent the disease from recurring. It is essential to use reliable contraception during treatment with vitamin A preparations of all kinds in women and girls of childbearing age. Otherwise, pregnancy could lead to serious deformities in the child.
Read more about this: Acne - That works best!
Cream containing vitamin A
Creams that contain preparations containing vitamin A can be used for various skin diseases. Most often they are used for acne. They counteract the excessive keratinization of the sebum ducts. This will reduce the occurrence of blackheads and reduce pimples. The inflammatory reaction, which plays an important role in acne, is also counteracted by the vitamin A in the cream.
Often the creams contain an additional active ingredient called benzoxyl peroxide. But there are also creams that only contain vitamin A preparations, which are also called retinoids, as an active ingredient. The advantage of a cream is that it can be used externally. This means that it is applied directly to the diseased skin and no medication has to be taken.
Nevertheless, there may be side effects of vitamin A therapy, as the active ingredient is also absorbed into the blood through the skin. However, the risk of adverse effects on the eyes or liver is significantly lower with a cream containing vitamin A than, for example, when the active ingredient is taken in tablet form.
Nevertheless, the creams require a prescription and should only be prescribed by a dermatologist after professional advice. Under no circumstances should they be passed on to third parties, even if they suffer from acne. A dermatologist must always be consulted before therapy can take place.
Eye drops containing vitamin A
In the case of dry eyes, eye drops containing vitamin A can be obtained on the advice of a doctor. Depending on the severity of the symptoms, a dropper is placed in the eye 3 times a day up to once an hour. The drops contain a small amount of the vitamin, which can specifically develop its effect on the eye. However, the dosage is not so great that there is a risk of oversupply. Therefore, the eye drops can also be used in pregnant women.
Short-term vision impairment can occur. Therefore, caution is required when driving and operating machines. The eye drops must not be given to people with hypersensitivity reactions to components of the drug. The vials are best stored in the refrigerator box to protect them from light. As with all medicines, it should be kept out of the reach of children.
Read more on the topic: Eye drops for dry eyes
Vitamin A in pregnancy
In women, the need for vitamin A is slightly higher during pregnancy because the growing child has to be cared for.
Vitamin A is important for the child's normal growth and development. A deficiency would therefore have particularly fatal consequences and would, for example, lead to deformities in the child.
However, caution is advised with the additional administration of vitamin A preparations, as it can easily lead to an oversupply (Hypervitaminosis). This also leads to growth disorders and damage to the eyes, liver and skin in the child.
As long as no deficiency has been proven, dietary supplements containing vitamin A should be avoided. The consumption of foods that are very rich in vitamin A, such as liver, should also be avoided during pregnancy.
A supply of provitamin A (also called β-carotene), as it is contained in plant sources, is harmless, as the body only converts it into the effective vitamin A when needed and therefore there is no risk of hypervitaminosis.
Read more on the topic: Vitamins in pregnancy
