Vitamin A has a distinction of being the first fat-soluble vitamin to be recognized. It may be one of the most versatile because of its role in several body processes. Up to a year’s supply of Vitamin A may be stored in the body, 90 percent of it in the liver. If you stop eating good food sources of the vitamin, deficiency symptoms will not begin to appear until after your stores are depleted. Insufficiency of Vitamin A is common in developing countries. Vitamin A deficiency is often accompanied by a severe zinc deficiency it is because zinc is needed to make retinol binding protein which transports vitamin A.
Therefore, a deficiency in zinc limits the body’s ability to move vitamin A stores from the liver to body tissues. There are several conditions which result from insufficient intake of Vitamin A. First is night blindness. In a condition known as keratomalacia, there is irreversible drying and degeneration of the cornea causing blindness. Second, deficiency of Vitamin A lessens the ability of the body to fight infections because of weakened immune system ability. In countries where such deficiency is common and immunization programs are limited, millions of children die each year from complications of infectious diseases such as measles.
In vitamin A-deficient individuals, cells lining the lungs lose their ability to remove disease-causing microorganisms. This may contribute to the pneumonia associated with vitamin A deficiency. Thirdly, Vitamin A deficiency in children may increase children’s risk of developing respiratory and diarrheal infections, decrease growth rate, slow bone development, and decrease likelihood of survival from serious illness. Moreover, a deficiency can occur when vitamin A is lost through chronic diarrhea and through an overall inadequate intake, as is often seen with protein-energy malnutrition.
Low blood retinol concentrations indicate depleted levels of vitamin A. This occurs with vitamin A deficiency but also can result from an inadequate intake of protein, calories, and zinc, since these nutrients are needed to make RBP. Iron deficiency can also affect vitamin A metabolism, and iron supplements provided to iron-deficient individuals may improve body stores of vitamin A and iron. Lastly, excess alcohol intake depletes vitamin A stores. Also, diets high in alcohol often do not provide recommended amounts of vitamin A.
It is very important for people who consume excessive amounts of alcohol to include good sources of vitamin A in their diets. On the other hand, excessive intake of Vitamin A would result to a condition known as Hypervitaminosis A. It refers to high storage levels of vitamin A in the body that can lead to toxic symptoms. There are four major adverse effects of Hypervitaminosis A: birth defects, liver abnormalities, reduced bone mineral density that may result in osteoporosis and central nervous system disorders.
Secondly, toxic symptoms can also arise after consuming very large amounts of preformed vitamin A over a short period of time. Signs of acute toxicity include nausea and vomiting, headache, dizziness, blurred vision, and muscular uncoordination. Although hypervitaminosis A can occur when large amounts of liver are regularly consumed, most cases result from taking excess amounts of the nutrient in supplements. Vitamin A, like all the rest of the vitamins, is necessary for our body against diseases common in our environment, regardless of any race one belongs to. As for Canadians, taking in supplements in pill forms is not enough.
They should take in primary sources of Vitamin A like beef, calf, chicken liver, eggs, and fish liver oils as well as dairy products including whole milk, whole milk yogurt, whole milk cottage, cheese, butter, cheese, dark green vegetables and fruits to increase their supply of vitamin A. Based on the articles, Canadians are aware of their health conditions and that taking in vitamins has become a part of their daily nutrition need. Despite the fact that Canadians are consciously aware of the importance of Vitamin A, still, everyone has to know the resulting conditions when intake of Vitamin A is deficient or excessive : http://www.health-topic.com/Article-Vitamin-A-46.aspx