Lack of vitamin A in the body has a detrimental effect on the hematopoietic system in the bone marrow. The deficiency causes a loss of important blood stem cells, scientists now report. They have identified a vitamin A metabolite known as retinoic acid that is vital to the process of activating and inactivating stem cells to regenerate cells. These findings may open up new prospects in cancer therapy.
Many specialized cells, such as in the skin, intestinal mucosa or blood, have a lifespan of only a few days. Therefore, steady replenishment of these cells is indispensable. They arise from so-called “adult” stem cells that divide continuously. When retinoic acid is absent, active stem cells are unable to return to a dormant state and mature into specialized blood cells instead.
Researchers hope the findings may play a role in cancer treatments because cancer cells, like stem cells, rest in a state of dormancy. The link for this article is posted in the description.
Vitamin A, a fat-soluble vitamin, is an essential nutrient which plays numerous important roles in human health. The most crucial ones include vision, proper growth and immune function.
Dietary sources of vitamin A fall into two categories – foods which contain preformed vitamin A and foods which contain provitamin A carotenes, compounds that are converted to vitamin A in the body.
The body’s ability to properly absorb preformed vitamin A is dependent on healthy mucosal cells plus the presence of bile, pancreatic enzymes, fat, protein and antioxidants. Absorption efficiency of vitamin A in the diet is typically high, about 80-90%. Some of the best sources of preformed vitamin A include liver, kidney, butter, whole milk, and fortified low-fat skim milk.
Conversion of provitamin A carotenes to vitamin A depends on the presence of protein, zinc, vitamin C and thyroid hormones. The absorption efficiency of beta-carotene is only about 40-60%. The body is able to convert beta-carotenes and other carotenes to vitamin A, and excellent sources of these provitamin A carotenes are dark green leafy vegetables like kale, spinach and collards; yellow-orange vegetables like carrots, yams, squash, and sweet potatoes; plus other foods like apricots, green peppers and dandelion root.
Vitamin A supplements could be helpful for health conditions such as AIDS and dry eyes, as well as respiratory tract infections like bronchitis and pneumonia. In addition, they could be used to help treat skin conditions and help with viral infections.
However, it must be noted that excessive supplementation with high doses of vitamin A, over 50,000 IU, can have detrimental health effects. It is thus advisable that any high-dose vitamin A therapy or regime be supervised by a nutrition-oriented health practitioner. Beta-carotene, on the other hand, exhibits no known toxicity.
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Vitamin A Deficiency Harms Stem Cells Impairing your Immune System, Vision and more… Prevent It
