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Sunday, May 18, 2008

Vitamin A: food sources and deficiency


Food sources of vitamin A

Preformed vitamin A commonly called as retinol is found only in animal foods. Fish liver oils and the liver of all animals are the richest sources but refrain from eating polar bear liver. It is so high in vitamin A that some people died from vitamin A overdose. Other sources include egg yolk, fatty fish like sardines and herring, butter, cheese, whole milk and other full-fat dairy products, liver and fish. Squash and other yellow vegetables are also rich sources of vitamin A. It can also be derived from fortified breakfast cereals, carrots, cantaloupes, sweet potatoes and spinach.

Diseases from deficiency of vitamin A

Night blindness is one of the first signs of vitamin A deficiency. People having deficiency in vitamin A suffer from night blindness and blindness. Vitamin A deficiency has been closely associated with xerophthalmia and other ocular lesions. This is because it makes the cornea very dry and damage the cornea and the retina. Vitamin A deficiency changes the differentiation state of typical epithelial cells. Deficiency was also related to increase rates of morbidity and mortality among children. There is a direct correlation between vitamin A and the immune system. Users must understand the context of vitamin A into the scheme of immune functions. However, the most common problems were diarrhea and respiratory infections. Health risk may include birth defects, liver abnormalities, central nervous system disorder and reduced bone mineral density that may result to osteoporosis.

Symptoms of acute toxicity

Nausea and vomiting, headache, dizziness, blurred vision and muscular uncoordination are common signs of acute toxicity.


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