Vitamins and their Functions

Our body needs several nutrients in order to work efficiently, it is similar to a machine that needs to be maintained in order to run smoothly. Some of these nutrients list include Vitamins which can be derived from the food we eat or from the man-made supplements that are readily available from your friendly drugstore.




Please find below the basic group of vitamins and their functions in the growth and maintenance of our body:



VITAMIN A (RETINOL):

Vitamin A plays a vital role in maintaining healthy skin, teeth, bone growth, reproduction, cell function and immunity (MedlinePlus). It is also known as retinol because it produces the pigments in the retina of the eye. It is found in both plant and animal sources, including whole milk, apples and leafy vegetables.


Vitamin A promotes good vision, especially in low light. It may also be needed for reproduction and breast-feeding.



Retinol is an active form of vitamin A. It is found in animal liver, whole milk, and some fortified foods.

Carotenoids are dark-colored dyes (pigments) found in plant foods that can turn into a form of vitamin A. There are more than 500 known carotenoids. One such carotenoid is beta-carotene.



Beta-carotene is an antioxidant. Antioxidants protect cells from damage caused by substances called free radicals. Free radicals are believed to contribute to certain chronic diseases and play a role in the aging processes.
Food sources of carotenoids such as beta-carotene may reduce the risk for cancer.
Beta-carotene supplements do not seem to reduce cancer risk.

Food Sources

Vitamin A comes from animal sources, such as eggs, meat, fortified milk, cheese, cream, liver, kidney, cod, and halibut fish oil. However, all of these sources -- except for skim milk that has been fortified with Vitamin A -- are high in saturated fat and cholesterol.

Sources of beta-carotene include:

Bright yellow and orange fruits such as cantaloupe, pink grapefruit, and apricots
Vegetables such as carrots, pumpkin, sweet potatoes, and winter squash
Other sources of beta-carotene include broccoli, spinach, and most dark green, leafy vegetables.

The more intense the color of a fruit or vegetable, the higher the beta-carotene content. Vegetable sources of beta-carotene are fat- and cholesterol-free.
Side Effects

If you don't get enough vitamin A, you are more likely to get infectious diseases and vision problems.

If you get too much vitamin A, you can become sick. Large doses of vitamin A can also cause birth defects.

Side Effects:

Acute vitamin A poisoning (Hypervitaminosis A) usually occurs when an adult takes several hundred thousand IUs of vitamin A. Symptoms of chronic vitamin A poisoning may occur in adults who regularly take more than 25,000 IU a day. Babies and children are more sensitive to vitamin A, and can become sick after taking smaller doses of vitamin A or vitamin A-containing products such as retinol (found in skin creams).


Large amounts of beta-carotene will not make you sick. However, increased amounts of beta-carotene can turn the skin yellow or orange. The skin color will return to normal once you reduce your intake of beta-carotene.

Recommendations

The best way to get the daily requirement of essential vitamins is to eat a wide variety of fruits, vegetables, fortified dairy foods, legumes (dried beans), lentils, and whole grains.


Factors, such as pregnancy and your health, are also important. Ask your doctor what dose is best for you.








Source: http://www.nlm.nih.gov/medlineplus/ency/article/002400.htm