Vitamin A is required for carrying out a number of vital processes in the human body. This vitamin is abundantly found in several foods, including fruits, vegetables, and meat. Find out some important dietary sources of this crucial vitamin, in this Story.
Vitamin A, commonly known as retinol, is a group of fat-soluble vitamins, that play a crucial role in many life-sustaining processes. It was discovered in 1917 by Elmer McCollum at the University of Wisconsin-Madison, and Lafayette Mendel and Thomas Osborne of Yale University.
Vitamins are generally classified as water-soluble and fat-soluble. Vitamin A belongs to the latter group, and occurs in different forms. It can be found as an alcohol (retinol), aldehyde (retinal), acid (retinoic acid), and also as an ester (retinyl palmitate).
Why Do We Need Vitamin A?
This vitamin plays an important role in several vital functions of the body. It is mainly required for maintaining healthy vision. It is also required for bone growth, cell division, and cell differentiation.
It is believed to have an enhancing effect on the immune system, as it facilitates the production of white blood cells (WBCs), including lymphocytes. White blood cells are essential for preventing any kind of infections.
Both retinol and retinoic acid play a significant role in embryonic development. Retinoic acid facilitates the formation of the heart, eyes, ears, and the limbs of the developing embryo. Vitamin A is also essential for maintaining the health of the urinary, respiratory, and the intestinal lining.
It is required for the growth of the thymus and the spleen as well. It can help maintain the health of the tooth enamel and gums, and repair tissues. This vitamin plays an important role in protein synthesis, and helps reduce the level of cholesterol in the body.
Dietary Sources
The dietary sources of this vitamin can be classified as the plant and animal food sources. Fruits and vegetables are the major plant-based foods that contain this vitamin. On the other hand, meat, fish, and foods derived from poultry are the main animal-based foods that can provide this vitamin.
Animal Food Sources In animal-based foods, this vitamin can be found as retinol. Retinol is usually converted into retinal and retinoic acid. Some important sources of this vitamin are, beef, chicken, eggs, fish, cheese, and seafood.
Plant Food Sources In plants, this vitamin is mainly found as provitamin A carotenoids. Some important carotenoids are carotene (alpha and beta carotene) and cryptoxanthin. Apricot, cantaloupe, mango, orange, apple, watermelon, plum, blackberry, peach, and kiwi are some fruits that contain this vitamin.
Among vegetables, carrot, pumpkin, broccoli, peas, spinach, sweet potato, turnip, tomatoes, wheat germ, escarole, collards, dandelion green, and mustard green are some other important sources of this vitamin.
However, cooking and storage can cause a significant loss of vitamin A from fruits and vegetables. Therefore, it is important to cover fruits and vegetables while storing them in the refrigerator. Raw fruits and vegetables can provide more vitamins than cooked vegetables or fruits. Furthermore, steamed or baked vegetables are more likely to retain the essential vitamins than the vegetables fried in excess oil.
Our body needs certain essential minerals, like zinc and iron, for the proper utilization of this vitamin. Zinc is required for the transportation of vitamin A from the storage organ liver to the tissues. On the other hand, this vitamin plays an important role in the metabolism of iron. Its deficiency can cause a number of diseases, including night blindness, which can eventually lead to complete blindness. A deficiency of this vitamin can also weaken the human immune system.
Studies have revealed that children with a mild deficiency of this vitamin are at an increased risk of developing respiratory diseases and diarrhea. So, It is important to include sufficient amounts of vitamin A-rich foods in your diet, along with iron and zinc.