About the Disease
Vitamin A deficiency can be accompanied by various biochemical disturbances, with the retina of the eye and skin cells being particularly sensitive. Vitamin A refers to a group of substances with similar chemical structures, including retinol and other retinoids, which exhibit similar biological effects. Vitamin A deficiency is a global problem, with children, pregnant women, and patients frequently suffering from infectious diseases and inflammatory processes being particularly at risk.
The physiological role of vitamin A in providing vision in low-light conditions was established in the first half of the 20th century. It was found that retinol and its “relatives” help synthesize visual pigments. However, the function of retinol is not limited to dark adaptation of the eyes. This vitamin is essential for all cells in the body, including skin cells. Research has shown that low levels of retinol and its analogs are often associated with colorectal cancer, xerophthalmia, Crohn’s disease, and other adverse consequences. In women, vitamin A deficiency can lead to menstrual cycle disorders and cervical ectopy, where the vaginal part of the cervix is covered by a single-layered cylindrical epithelium, which has a lower protective potential. Vitamin A is also necessary for the normal tissue maturation of the lungs.
Types
From an etiological point of view, two types of vitamin A hypovitaminosis are distinguished:
Primary – associated with nutritional deficiency;
Secondary – develops against the background of concomitant pathologies, including infections.
In terms of clinical course, three stages of vitamin A deficiency in the body are distinguished:
First – clinical manifestations are absent, deficiency is detected only by laboratory methods;
Second – symptoms appear affecting the eyes and skin, and a slight decrease in immune activity is observed (treatment is carried out with orally administered drugs);
Third – severe disturbances occur, including organ insufficiency (therapeutic drugs are administered by injection).
Symptoms of Vitamin A Deficiency
The earliest symptom of vitamin A deficiency is impaired night vision, where visual acuity sharply decreases in poor lighting. Insufficient retinol in the bodies of adults and children negatively affects the condition of epitheliocytes, which are the main cells of the skin and mucous membranes. This is accompanied by the following processes:
Follicular hyperkeratosis – increased keratinization of hair follicles, leading to the appearance of “goosebumps”;
Erosive-ulcerative lesions of the mucous membrane of the digestive tract;
Inflammatory processes affecting the bronchi, bladder, and urethra.
How does epithelial damage, resulting from depletion of vitamin A reserves in the body, manifest? The main symptoms in men and women include:
Dryness and flaking of the skin;
Roughness of the skin (due to follicular damage);
Brittleness of nails and loss of natural shine of nail plates;
Dryness of the eye conjunctiva (shedding of the epithelium clogs tear ducts) – over time, xerophthalmia is replaced by keratomalacia, where ulcers form on the softened mucous membrane;
Loss of transparency of the cornea due to secondary infection.
Causes of Vitamin A Deficiency
Vitamin A is a group of substances that are well soluble in fats and poorly soluble in water, while performing similar functions. The main representatives of this class are retinol, retinal, and retinoic acid. Food products contain both active vitamins and their proforms. The most significant provitamin is β-carotene, the metabolism of which in the body leads to the formation of two molecules of retinol. Retinyl esters break down in the small intestine, releasing retinol. Carotenes are found in plant products. However, their bioavailability, compared to animal sources, is low – only 1/6 is absorbed. Therefore, it is important to consume both plant-based and animal-based foods to meet the body’s vitamin A needs.
The main causes of vitamin A hypovitaminosis can be:
Insufficient intake of vitamin from food products;
Diseases of the digestive system, which disrupt the absorption of the vitamin;
Previous operations on the gastrointestinal tract;
Increased needs during infections, pregnancy, and periods of active child growth.
Diagnosis
In the presence of clinical signs suspicious of vitamin A deficiency, the following examinations are indicated:
Evaluation of retinol levels in the blood;
Measurement of retinol-binding protein concentration;
Electroretinography – assessment of the electrical activity of the retina;
Ophthalmoscopy – examination of the fundus of the eye;
Determination of visual acuity;
Assessment of dark adaptation of the eyes;
Radiography of the gastrointestinal tract with contrast.
Treatment of Vitamin A Deficiency
Treatment of vitamin A deficiency is carried out using appropriate vitamin preparations, which may be available in oral or injectable forms.
Conservative Treatment
According to clinical recommendations, in cases of established vitamin A deficiency, replenishing its reserves in the body solely through dietary products is not effective. Medicinal preparations containing retinol and analogs are required. Retinol can also be used topically (ointment, oil solution) for inflammatory skin conditions and conditions associated with dryness and slow healing (dermatitis, eczema, atopic dermatitis outside exacerbation, cheilitis, fissures). Local forms of retinol are also used to activate reparative processes in various dermatoses.
Surgical Treatment
Surgery may be indicated only for certain gastrointestinal disorders associated with impaired absorption, requiring surgical correction alone to prevent recurrence of hypovitaminosis.
Prevention of Vitamin A Deficiency
Prevention of vitamin A deficiency involves balanced nutrition with sufficient intake of orange vegetables and fruits, as well as butter, eggs, seeds, and other foods rich in this nutrient.
Rehabilitation
After the main course of treatment, supportive therapy is recommended to replenish retinol stores in the body’s depot. Proper nutrition is also important.