NUSCTX 10 Lecture Notes - Lecture 10: Bone Density, Xerophthalmia, Low-Density Lipoprotein
Document Summary
Fat-soluble vitamins require bile acids for absorption. Fat-soluble vitamins require digestive enzymes for absorption. Small intestine absorbs fat-soluble vitamins similarly to fat absorption i. e. they are packaged into chylomicrons. Need a healthy digestive system to process these vitamins correctly. Compounds that support the physiological functions of vitamin a. Retinoic acid (ra): systemic vitamin a functions as a regulator of gene. Vitamin a vis retinoic acid is essential for all vertebrate reproduction and life. Retinal (vision), skin, epithelial differentiation, immune function, thymus, reproduction. Severe vitamin a deficiency causes xerophthalmia (depletion of ra) Can mess up testis and vitamin a function. Single dose: 100-fold > rda in adults. With adequate exposure to sunlight there is no need for dietary vitamin d. Can dye both ways, but one way is much faster than the other. Causes: lack of ca++ / vitamin d or failure to convert vitamin d into calcitriol or failure of calcitriol to regulate gene expression.