Vitamin A deficiency
Vitamin A deficiency
Description, Causes and Risk Factors:
Vitamin A: Any ionone derivative, except provitamin A carotenoids, possessing qualitatively the biological activity of retinol.
Vitamin A deficiency is a common form of micronutrient malnutrition affecting 21.1% of preschool-age children and 5.6% of pregnant women worldwide. Vitamin A is most critical for vision, but it is also important for the maintenance of the skin, lungs, and intestinal tract.
Vitamin A is found in meat and dairy products, as well as fruits and vegetables. It is a fat-soluble substance that is divided into retinol and provitamin A. Retinol is the active form of vitamin A usually found in animal products, while provitamin A is found in fruits and vegetables.
Vitamin A plays several crucial roles in the human body. In the retina of the eyes, it is needed for the adaptation to darkness. Beside that, vitamin A is important in all body tissues to maintain growth and health of cells. In particular, epithelial cells are affected by lack of vitamin A, leading weakening of the immune system and to irreversible blindness due to eye lesions.
Vitamin A deficiency occurs when too little vitamin A is present in the food over a long period. Vitamin A is fat soluble and excessive vitamin A can be stored in the liver, so vitamin A deficiency does not occurs immediately when there is no vitamin A in food, but when the storage in the body has been exhausted.
For children, lack of vitamin A causes severe visual impairment and blindness, and significantly increases the risk of severe illness, and even death, from such common childhood infections as diarrheal disease and measles.
For pregnant women in high-risk areas, vitamin A deficiency occurs especially during the last trimester when demand by both the unborn child and the mother is highest. The mother's deficiency is demonstrated by the high prevalence of night blindness during this period.
Sources of vitamin A include: Paprika, red pepper, cayenne, liver, meat, sweet potato, carrot, dark leafy greens, butternut squash, lettuce, dried apricots, cantaloupe, papaya, mangoes, green peas, peaches, whole milk,
Health Benefits of Vitamin A:
Proper Immune Functioning - Vitamin A is essential to regulate the immune system, and plays a key role in making white blood cells which fight off infections in the body.
Cancer Protection - Studies suggest beta-carotene and vitamin A lower risk of many types of cancer. This effect could mainly be from a diet high in vegetables and not from supplements.
Increased Protection from Bacterial and Viral Infections - Vitamin A is essential for healthy surface linings of the eyes, mucous membranes, respiratory, urinary, and intestinal tracts.
There is an increased susceptibility to infections, especially of the respiratory tract, in the form of frequent and prolonged common colds.
Vitamin A deficiency may lead to lack of appetite and vigor, defective teeth and gums, skin disorders such as pimples, acne, boils, and premature wrinkles.
When vitamin A is present in insufficient amounts, the mucous membranes of the nose, throat, and mouth, the bronchial tubes, lungs, intestinal tract, kidneys, and vagina are greatly affected. Eventually the mucous membranes of the entire body lose their ability to secrete the normal quantities of mucus needed to protect them from irritation, and the body degenerates rapidly.
Prolonged deficiency of vitamin A may result in inflammation of the eyes, poor vision, and night blindness.
Diagnosis may include the following investigations:
Zinc level (zinc deficiency interferes with production of retinol-binding protein).
Iron studies (iron deficiency can affect the metabolism of vitamin A).
FBC: anaemia and infection may occur.
Renal function tests, electrolytes and LFTs to evaluate for nutritional and hydration status.
In children, X-rays of the long bones may be useful to evaluate bone growth and for excessive deposition of periosteal bone.
Dark-adaptation threshold should be tested.
Serum retinol study is costly. Serum retinol-binding protein study is easier to perform and less expensive.
Supplements of vitamin A are also used to help correct the deficiency or prevent if from occurring.
Premature infants are at risk for vitamin A deficiency and are often given supplements after birth. Too much vitamin A given to children could be toxic, while too little increases a child's risk for infection.
Women in their first trimester of pregnancy should also be careful not to take too much vitamin A.
Treatment for subclinical vitamin A deficiency includes the consumption of vitamin A-rich foods for example, liver, beef, chicken, eggs, fortified milk, carrots, mangoes, sweet potatoes and leafy green vegetables.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.
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