Deficiency of Vitamin A

Résultat de recherche d'images pour "vitamin a deficiency"Deficiency of vitamin A is not common in the United States; however, it is a serious public health problem in some other countries. Vitamin A is a fat-soluble vitamin which plays a role in vision, bone growth, reproduction, cell division, normal growth, and maintenance of healthy skin in humans. This compound also has a function in the production and activity of white blood cells for the immune system.

Vitamin A has an important role in the maintenance of mucous membranes and surface lining of many systems of the body.

Every year a quarter to a half million children in developing countries become blind because of vitamin A deficiency. Moreover, millions of children die in these countries each year from infectious diseases such as measles because of diets which are deficient in the vitamin and inadequate availability of immunizations.

Vitamin A deficiency may lead to decline in resistance to infection, night blindness, poor growth in children, weak bones and teeth, inflammation of the eyes, diarrhea, and loss of appetite. There is an association between pneumonia and deficiency of the vitamin. In the United States, vitamin A deficiency does occur in alcoholic patients, and it occurs in children as a subclinical form with no symptoms.

The use of vitamin A supplementation in patients with alcoholism is problematic because these clients tend to have liver problems from their consumption of alcohol. Since vitamin A stores in the human liver, this would place too much burden on that organ. Hence, they should obtain vitamin A from their food intake in conjunction with cessation of alcohol use.

Subclinical vitamin A deficiency

The subclinical form in the United States involves low storage of the vitamin in the liver. Children who live in areas of the country with poor access to health care are at risk for this condition. Toddlers and preschool age children may develop it as well. Pediatric patients who live in poverty or in areas where nutritional deficiency is prevalent are also at risk for the asymptomatic form of vitamin A deficiency.

Children in the United States who are recent immigrants or refugees from developing countries where deficiency of vitamin A or measles is quite prevalent may have the subclinical form. Moreover, children with diseases of the liver, pancreas, intestines, or problems with the absorption or digestion of fat are at risk for subclinical vitamin A deficiency.

The subclinical form of vitamin A deficiency is not as severe as symptomatic cases of the condition. In fact, patients with subclinical deficiency still have some liver storage of vitamin A though in smaller amounts than a person with normal supply of the vitamin. Nevertheless, patients with subclinical vitamin A deficiency will still encounter the same or similar health problems that individuals with severe vitamin A deficiency will have.

Vitamin A deficiency occurs in the United States when a person is under strict dietary restrictions. In general such restrictions will accompany deficiency of zinc, and that will impair the body’s ability to mobilize vitamin A from liver stores to other tissues.

Vegetarians require additional vitamin A because the supply that they receive from plant food does not absorb through the gastrointestinal tract as well as vitamin A from animal sources. Therefore, strict vegetarians who do not consume eggs and dairy products require at least five servings of fruit and vegetables each day to meet this need.

Patients with malabsorption problems of the gastrointestinal tract such as celiac disease or Crohn disease are at risk for vitamin A deficiency.

Food sources of vitamin A

To obtain enough vitamin A one must understand that it occurs in two forms from food sources. Animal sources supply retinol, or preformed vitamin A, which is almost ready for use by the human body after absorption from the gastrointestinal system. Eggs, milk, liver, margarine, some fortified food products, meat, cheese, kidney, cod, and halibut fish oil contain animal or preformed vitamin A.

Vitamin A from plants occurs as beta carotene, and one can obtain this from colorful fruits and vegetables such as carrots, canteloupes, sweet potatoes, spinach, squash, broccoli, peaches, apricots, mangos, kale, and pink grapefruit. The advantage of plant vitamin A is that it converts to preformed vitamin A in the small intestine, and it does not appear that one can obtain too much beta carotene.

Animal or preformed vitamin A, however, may become toxic if one consumes large amounts of it from unnecessary supplementation.

One of the first clinical signs of vitamin A deficiency is night blindness, and it is interesting to note that in ancient Egypt, people treated this medical condition with the consumption of liver.

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