What Vitamin A,
Vitamin A occurs only in the fatty phase of food in the animal origin. Plant foods contain yellow, orange and red colored pigment called carotenes (Provit5amin A) which gives color to vegetables & fruits. Carotene pigments are converted to Vitamin A in the body. Pure vitamin A is a pale yellow crystalline compound occurring in the animal kingdom. Vitamin A is measured in International unit or micro gram.
foods that contain vitamin a:
Egg yolk, butter, cheese, whole milk, fish and meat, fish liver oil are the richest natural source, butter and egg also good source.
All yellow, orange and red food and vegetables such as carrots, pumpkin, mango, papaya, peaches, apricots, and all green leafy vegetables.
we suggest some best vitamin A supplement you can check here .
Effects of vitamin a deficiency
The best understood effects of vitamin A is related maintenance the visual function and vision with dim light. Rhodopsin present in the retina which is required for vision in dim light. It is formed when vitamin A combines with protein opsin. In bright light Rhodopsin absorbs light and breakdown into protein opsin and retinal. In dim light retinal and Opsin recombine rapidly to form Rhodopsin, provided the is an adequate supply of vitamin A.
Another important effects of vitamin A is the maintenance and integrity of epithelial tissue which forms outermost lining skin and innermost lining of mucous membranes of respiratory, gastrointestinal, genitourinary, eyes, etc.
Bone and tooth development:
Vitamin A is needed for skeletal growth and tooth development.
It helps thy body to fight against infection by keeping mucous membranes in a healthy condition which act as a barrier to infection.
Vitamin A may protect against some epithelial cancer like bronchial cancer.
Deficiency of vitamin A:
Night blindness or nyctalopia:
It is one of the earliest signs of vitamin A. In this condition, the subject can not see in dim light. Especially after coming from a bright light area.
In this condition the conjunctiva of eye becomes dry, thickened and pigmented. Conjunctiva appears smoky, smooth shiny.
These spots are triangular pearly white or yellowish foamy spot in the conjunctiva. Its usually common in children.
The whole cornea may becomes soft and burst. If eye is collapse, vision is lost permanently.
This stage is particularly serious. The cornea appears dull, dry. In severe cases its can be corneal ulcer.