Vitamin A is required for night vision, bone and tooth development, maintaining skin tissue, reproduction, mucous membranes, and for iron metabolism. There are two sources of Vitamins A. The active form are obtained from animal products and are immediately available to the human body and the precursors types that must be converted to active forms to be utilized by the body. They are acquired from fruits and vegetables that have yellow, orange and dark green pigments, known as beta-carotene.
Vitamin A is also involved in maintaining the certain cells used by immune system to ward off infections and include b-cells, t-cells, macrophages, and natural killer cells. Vitamins A affect the production of the human growth hormone.
Vitamin A is a fat-soluble vitamin and is stored primarily in the liver and to some extent the fat cells in the body. When needed the liver releases the Vitamin A into the blood stream to be carried to the cells and organs of the human body.
Unlike water-soluble vitamins, fat-soluble vitamins can reach toxic levels in the human body. The condition knows as hypervitamoinosis can occur if more than 10,000 IU per day of Active (animal) Vitamin A, or the synthetic version of Vitamin A is taken. This condition can be fatal. Do not take more than the recommended dosage of Vitamin A. Vitamin A derived from fruits and vegetables does not appear to develop toxic levels in the human body.
It is unknown why, but animals adapted to the polar environment contain high enough amounts of Vitamin A in their livers to be toxic to humans. As little of 30 grams of polar bear liver eaten in one meal can be enough to kill a human being.
Vitamin A in the form of Retinoid and Retinol are used in the cosmetic industry to improve the skin replacement rate. The effects of acne and the scars from acne can be markedly reduced by this higher skin cell replacement rate. The anti aging chemicals also found in vitamin A are absorbed through the skin and can increase the collagen level giving the skin a more youthful appearance.
Regular application of retinol can make the skin soft and smooth. The pores will be cleaned and less visible and wrinkles will be less pronounced thus the signs of aging would be reduced. Retinol has been found to improve skin texture, tone and color.
Vitamins A had been suspected to be a contributor to osteoporosis and with the increase in birth defects when taken in excess. The FDA recommends that pregnant women consume no more than 5,000 IU of Vitamin A per day.
Good sources of natural Vitamin A is found in sweet potatoes, carrots, collard greens, kale, pumpkin, spinach, sweet peppers, winter squash, apricots, cantaloupe, mango, liver, eggs and broccoli.
Always consult your doctor before using this information.
This Article is nutritional in nature and is not to be construed as medical advice.