Sweet potatoes are a great source of carotenoids.

Did you know that vitamin A can be very beneficial to your eyes? If your body lacks vitamin A, you are at risk for blindness. However, too much of it can be harmful to your body.

Vitamin A: What is it?

Vitamin A is plays a huge role in bone growth, vision, as well as in your immune system’s health. When it comes to the eyes, this powerful vitamin can help make your mucous membranes and eye surface ward off viruses and bacteria, thus lessening the risk of eye diseases and infections. It can also protect the skin and body in general against viruses and bacteria.

Generally, there are two kinds of vitamin A. The first kind, retinol, is derived from animal food sources. This type can be directly used by the body. Its best sources include beef, whole milk, cheese, and chicken liver. The second kind is known as carotenoids, which can be obtained through fruits and vegetables. Carotenoids are converted to retinol during digestion, and can be found in carrots, sweet potatoes, canteloupes and kale.

Benefits of Beta Carotene and Vitamin A to the Eyes

When combined with other vitamin antioxidants, vitamin A can play a huge role in minimizing the risk for age-related macular degeneration (AMD). In the Age-Related Eye Disease Study (AREDS), those who were more at risk for AMD and who took multivitamins with vitamin A, C, E, and copper everyday showed a 25 percent reduction in the risks for advanced AMD in a 6 year time span.

Retinol is obtained from animal products, like whole milk.

It is also known that a mixture of lutein and vitamin A can prolong vision in individuals who are suffering from an eye condition known as retinitis pigmentosa, which is a rare, inherited disease that will eventually lead to blindness. A Harvard School of Medicine study discovered that people with this disease could slow the progression of peripheral vision loss bye consuming daily doses of vitamin A and lutein.

Deficiency in Vitamin A 

Deficiency in vitamin A is a rare in developed countries. Sadly, it is much more common in underdeveloped countries. Around the world, nearly half a million children develop blindness due to vitamin A deficiency every year which, with the right diet, could have been preventable.

If a person is deficient of vitamin A, the cornea grows dry and become cloudy. Vision loss and corneal ulcers then follow. Deficiency in vitamin A can also lead to retinal damage which then leads to blindness. Because of  the fact that vitamin A is crucial for infection resistance and the maintenance of a healthy immune system, a deficiency of it can eventually bring to death due to respiratory disorders and severe infections.

Daily Value of Vitamin A

In all cases, the best way to acquire the right amount of vitamins and minerals is through a well-balanced and healthy diet. Daily value’s (DV) concept was made to guide consumers in knowing if a food has more or little nutrients in accordance with its Recommended Daily Allowance (RDA). As for vitamin A, its DV is 5,000 IU.

Plant-based vitamin A is water soluble and can be easily flushed from the body.

Toxicity of Vitamin A

When vitamin A comes from animals, it is not water soluble, and thus cannot be simply flushed by the body. Instead, the body stores it in body fat, where it can build up in the body and can be very toxic when consumed in large amounts.

Carotenoids and beta carotene found in vegetables and fruits are not toxic to the body since they are water soluble, and can be simply flushed by the body.

As for smokers, beta carotene supplements present serious risks to them. Studies have found that smokers who took daily supplements of 20-30 mg beta carotene posed higher risks of lung cancer in contrast to those who didn't take any supplements at all.

The Institute of Medicine has developed upper intake levels for vitamin A which are animal based in order to help lessen the risk of toxicity. 3000 IU is recommended for children ages 4 to 8 and 5,610 IU for 9 to 13 years old. As for teenagers ages 14 to 18, 9240 is adequate and 10000 IU for adults ages 19 and older is an acceptable level.

Probable reaction of toxicity due to long term vitamin A consumption above these given levels include liver abnormalities, reduced mineral density of the bone, birth defects, central nervous system disorders, and osteoporosis.