vitamin A: regulate the metabolism of bone narrow



Vitamin A is an essential, fat-soluble vitamin found naturally in both animal and plant sources. Fat-soluble means that the vitamin will dissolve in fatty foods. Fat-soluble also means that the vitamin will be stored in the fat in the body. Because it is stored in the body, it is not necessary to replenish it on a daily basis, as is necessary with water-soluble vitamins.Vitamin A occurs in two forms: retinol and retinoids. The active form of the vitamin, called retinoids, is found naturally in animal products. The inactive form (also called Òpreformed” or ÒprevitaminÓ), called carotenoids, is found naturally in plant sources. Inactive forms of the vitamin are converted in to the active form in the body where it is then used in a number of functions.

What Vitamin A Does



Vitamin A plays a vital role in several key functions in the body. Recent research finds that it aids in gene transcription, which is important not only for developing embryos, but also for maintaining health and wellness on a daily basis. Vitamin A also takes part in other reproductive functions as well. Vitamin A has specific immune functions it achieves in the body. By helping regulate the metabolism of bone marrow, this vitamin contributes to the production of red and white blood cells. It has been shown to help lower the risk of heart disease, as well as some types of cancer due to its antioxidant activity. Antioxidants aid in preventing free radicals or ÒoxidantsÓ from attacking healthy and developing cells. Vitamin A also has been shown to be crucial for vision by aiding in the development of rhodopsin, a pigment in the retina responsible for maintaining the rod cells in the eye. The primary function of the rods is to receive black and white color. Maintaining adequate levels of rhodopsin in the retina prevents night vision blindness. Another benefit of Vitamin A is for the skin. Vitamin A has been shown to significantly reduce not only the size of the sebaceous glands, but also the amount of sebum secreted by those glands. Sebum is a product of the sebaceous glands that not only clogs the pores causing acne, but also serves as a nutrient source for bacteria on the skinÕs surface, thus furthering the development of acne. Besides in the case of acne, vitamin A is vital for preventing other skin disorders. The vitamin is essential for keeping cells healthy that line the organs such as the nose, mouth, lungs, vagina, rectum and intestinal tract.

Food Sources of Vitamin A

Some food sources high in Vitamin A include: liver (beef, pork, poultry and fish), carrots, sweet potatoes, kale, butter, spinach, pumpkin, collard greens, cantaloupe, eggs, apricots, papaya, mango, peas and broccoli. Generally, if a fruit or vegetable is bright orange or red or dark green, it is a good source of vitamin A. A sweet potato has a higher vitamin A content than a carrot. Animal liver is thought to be the best natural source of Vitamin A providing over 700% of the recommended daily value (based on a 2000 calorie diet). Vitamin A is measured in IU which are international units.

How Much Vitamin A Do You Need?

Adults need 2310 IU to 3000 IU per day but in pregnancy those values rise to 2500 IU to 2565 IU. During breastfeeding, the amount of vitamin A that is needed is between 4000 IU and 4300 IU.

Vitamin A Deficiency Symptoms



Night vision blindness, also called night blindness, is one of the first signs of a deficiency. This is seen in individuals who cannot see where they are going in movie theaters when the lights are out and also in those who have difficulty driving at night.Dry eyes, impaired immunity, thin enamel on teeth, softening of the cornea, and total blindness will eventually result from a vitamin A deficiency.

Vitamin A Toxicity

Toxicity is rare. Symptoms include anorexia, nausea, jaundice, blurry vision, vomiting, drowsiness, headaches and muscle/abdominal pain. An intake of over 100,000 IU per day for more than six months is necessary for toxicity to occur. Symptoms showing less toxicity include fever, dry mucous membranes, fatigue, weight loss, bone fractures, hair loss, anemia, and diarrhea. Because vitamin A competes for receptors on bone with vitamin D, it’s possible that higher than normal levels of vitamin A consumed for long periods of time could cause osteoporosis, but this has only been proven in animals not humans.


References
1- Dunne, Lavon. Nutrition Almanac, McGraw-Hill Publishing, 2002.
2- Wikipedia.


'Health is wealth' and with poor health you'd loose all your wealth. So begin today to live a healthy life to save and enjoy your wealth. “You are what you eat” it is often said. That’s why our focus is to help you find the right products for you.

Click Here to Order

Custom Search