February 21, 2017

Fat-soluble vitamin- A

Vitamin A

Vitamin A is very important in organism and can be found in animals products. It performs many functions:

– necessary in the process of view- retinal is component of rhodopsin ( it’s photosensitive pigment located in retinal rods). Vitamin A regulates arising process of new cells, so to have good sight, we have to eat products rich in vitamin A,

– responsible for proper action of skin and mucous membrane preventing from infection,

– improves immunity- maintains efficiency of thymus; in thymus accelerates lymphocytes T.  Vitamin A increases producing blood cells: granulocytes and leukocytes,

– takes part in lipids and hormones (especially thyroids hormones) conversion.

Pro-vitamins A- carotenoids

– mostly plants products,

– most important is beta-carotene,

– from 1 beta-carotene will arise 2 vitamins A,

– this conversion beta-carotene in vitamin A has  place in intestine epithelium and in liver, also needs in process zinc.

Beta-carotene is natural antioxidant and prevents organism from free radicals. In deficient of beta-carotene free radicals will damage nucleus in cells and can cause heart disorders, cancers, cataract and fast agening. Risk these disorders decrease following vitamins: E and C and also one mineral- selenium.

Deficient of vitamin A:

– dry and swelling conjunctiva, dry cornea,

–  inflammations of eyelids,

– disorders in regenerating visual purpure- rhodopsin and caused by this- night-blindnesses,

– vitamin A cooperates with Growth Hormone,

– dry and scaly skin,

– drying epithelium in respiratory system, digestive system and in urinary system,

– very sensitive on deficient are lungs, that’s why can occur often inflammations.

Where can we find vitamin A:

– blubber,

– livers,

– full fat milk- 3,2%,

– butter,

– cheese,

– egg yolks,

– sour cream,

– meat.

Where can we find carotenoids:

– vegetables and fruits in yellow, red, green color, such as: carrots, pumpkin, green beans, apricots and peaches,

– also in dill, parsley, cabbage, lettuce, spinach and sorrel,

– moreover small amounts in milk, cheese.

Vitamin A is resistant during cooking, but another types of  cooking processes, such as: frying, baking will cause loss till 25%.

Vitamin A is very photosensitive and keeping butter in improper conditions will cause loss till 70%.

Hypervitaminosis (excessive amounts of vitamin A in organism) is dangerous, because it will cumulate in liver, it’s not excreted and that’s why it’s toxic.

Toxic dose for adults is 15 000 ug and for kids 6 000 ug.

High intaking vitamin A by pregnant women (above 3 300 ug per day) can cause birth defects.

High intaking carotenoids isn’t toxic.

 

 

 

Comments

  1. Great post :*

  2. Very useful. Thanks!

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