Vitamin A (Retinol)

A fat-soluble vitamin contained in significant quantities in fat and especially in sea fish liver, butter, egg yolk, and cattle liver. As a provitamin (beta-carotene), it is present in many plants, especially those colored yellow-orange (carrots, red pepper, gooseberries, currants, rose hips, rowan, sea buckthorn, apricots). Beta-carotene is cleaved into two vitamin molecules by carotinase in the intestinal wall. It is absorbed in the intestine after the emulsification of fats by bile acids. It performs two important functions in the body. It participates in the formation of the visual pigment rhodopsin, which ensures the adaptation of the eye to darkness, i.e., twilight vision. Therefore, with Vitamin A deficiency, the ability to see in twilight suffers (hemeralopia or "night blindness"). Also, retinol participates in the process of growth and differentiation of epithelial linings. With a lack of Vitamin A, metaplasia of epithelial cells develops in various organs and their transformation into stratified squamous keratinizing epithelium. Vitamin deficiency can be associated with its insufficient content in food or with malabsorption caused by liver diseases and a decrease in its bile-forming and excretory functions.

Within 6 days. The specified time does not include the day of biomaterial collection