Vitamin A deficiency causes many serious medical conditions such as night blindness and xerophthalmia( dry eye), Failure of rhodopsin formation in the retina induces loss of vision, defects in bone growth, failure to produce sperms in the male body, Miscarriage during pregnancy and defects in growth in children, most susceptible to infections so on.
Vitamin A is necessary for our growth, health and life too because the absence of Vitamin A ruins life causing eventual die. Vitamin A is basically important in the development of young, growing animals. It is important for reproduction in our body. Retinoic acid is a form of vitamin A which is performed as a hormone. The research was done to find out the retinoic acid and vitamins A. According to the results the rats who were given retinoic acid were healthy in all aspects but failed to give birth to their fetuses and also male rats were healthy but weren’t produced sperm and both senses were blind.
As mentioned earlier Vitamin A is important for our vision.
Also, maintenance of Normal epithelium which is lining many of our body cavities and organs such as respiratory urogenital gastrointestinal are protected by mucous membranes. The epithelial lining of some places in our body is keratinized causing prevention of the entrance of harmful microorganisms but deficiency of vitamin A causing entrance of pathogens through the keratinized epithelium of skin, lung, gastrointestinal tract and urogenital tract surface. A sufficient amount of dietary vitamin A is needed for the maintenance of normal resistance to pathogens and diseases.
Vitamin A aids in the development of healthy bones. It is causing excessive deposition of bones.
The deficiency of vitamin A increases the frequency and severity of bacterial, protozoal and viral infections as well as other disease conditions too.
In our body disease resistance is done by mucosal protection and corticosteroids production of the adrenal gland which is battling against the pathogens.
Even though you have to understand the importance of optimal vitamin A level in the body because both deficient and excessive status defeats the immune function.
Some research has found developing cancer in vitamin A-deficient animals is higher than in animals receiving normal vitamin A intakes.
Requirements for a sufficient daily intake of vitamin A have been published in the United States by the committee on animal Nutrition Academy of Science National Research Council. Vitamin A requirement can be expressed on the basic of IU per kilogram of body weight, on a daily basis or as a unit of diet.
The median intake of vitamin A range from 744 to 811 microgram RAE per day for men and 530 to 716 microgram RAE per day for women. For the children, it is 400-700 microgram RAE per day, when lactating it is 1200-1300 microgram RAE per day.
The most abundant sources of vitamin A are fish oils. If you believe it or not some swordfish liver oils contain as many as 250, 000 IU of vitamin A per gram and also halibut liver oils and cod liver oils are rich in vitamin A sources. Foods of animal origin, milk, fat, egg yolk and liver are plentiful sources for vitamin A.
When we are considering milk, skim milk contains a very little amount of vitamin A.Egg yolk contains 0.9,6.3 and 16.3 IU/g respectively.
Reference; Vitamins in Animal and Human Nutrition(Lee Russell McDowell)
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