vitamin a
February 17, 2008
Everything You Need To Know About Vitamin A
Vitamin A is important to the body. It isn’t only a single compound, it comes in various forms. It comes in the form of alcohol as retinol, as well as aldehyde in the form of retinal. It also comes in the form of acid which is retinoic acid.
Vitamin A contains a Beta-ionone ring which is attached to an isoprenoid chain. This is the normal structure of the Vitamin A nutrient. Retinol is the animal form and is a fat-soluble and anti-oxidant vitamin that is important to a persons vision as well as bone growth.
It is a retinoid that is chemically related to one another. This is also used in medicines.
RDA for Vitamin A as supervised by the Food and Nutrition Board is that a daily dosage must be taken in order to support the normal functioning of the body; be it immune functions, reproductive functions, genes or visions.
For infants up to 6 months old, they are required to have an intake of 400 mcg. For infants that are 7 to 12 months old, they are required 500 mcg. For children 1 to 3 years of age, they must have 300 mcg. For children 4 to 8 years of age, they are required to have 400 mcg. For children 9 to 13, they must have 600 mcg. For teenagers 14 to 18 years old, the males must have 900 mcg while the females are okay with 700 mcg. For adults, males are required to have 900 mcg while females must have 700 mcg.
Vitamin A intake also varies for pregnant women. Women aged 18 years or younger must have 750 mcg. Pregnant women who are 19 years and older must have 770 mcg. The Vitamin A intake also changes when the female is breastfeeding. For those younger than 18, they are required to have 1200 mcg. For those who are 19 and older, they must have 1300 mcg.
Vitamin A may be found in yellow and orange vegetables. Green vegetables contain carotenoids too. There are a number of healthy foods which contain Vitamin A and retinol. These are cod liver oil, breakfast cereals, eggs, butter, milk, sweet potatoes, carrots, cantaloupes, spinach, squash and butternut.
Vitamin A deficiency results in:
1. Nyctalopia or Night Blindness
This is a condition which makes it impossible or difficult for the individual to see in a low light scenario. This is the symptom of other eye diseases. Night blindness may be apparent at birth or it may be rooted from the lack of Vitamin A. This is a disorder that affects the rod cells found in the retina. The rod cells lose their ability in responding toward the light. People who suffer this disease have poor vision in the dark.
2. Xeroxis or Corneal Drying
This may have different causes which includes dehydration, diabetes and lack of Vitamin A. The treatment is symptomatic. You can consult with an eye doctor. The usual diagnosis is eye drops.
3. Bitot’s Spots
These are triangular spots found in the eyes. They are similar to floaters (which are like spider webs in the eyes.) Just like xeroxis, this can be cured by eye drops prescribed by eye doctors.
4. Xerophthalmia
This is a medical condition where the eye can’t produce tears. It is caused by the lack of Vitamin A. It also implies a dryness that is destructive to the epithelium. The condition usually occurs in developing countries because of its environment and surrounding. Other forms of xeropthalmia come with aging, scarring from injuries or autoimmune diseases like arthritis.
5. Keratomalacia
Is an eye ailment that leads to the cornea drying up. It may also be caused by dehydration as much as it is caused by lack of Vitamin A. Now this is quite dangerous because it might lead to glaucoma and the individual may lose his or her sight permanently if not remedied as soon as possible.
Vitamin A deficiency is considered to be risky especially if it results in other diseases such as respiratory problems and infection. IT affects children more than it affects adults. Those who lack Vitamin A eventually suffer diarrhea and measles. Those who are already HIV-infected and lack Vitamin A have a harder time getting cured.