NUTR 2105 Lecture Notes - Lecture 11: Hemolysis, Vitamin K, Osteoporosis
10 Apr 2017
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Excess stored in liver and adipose tissue. No readily excreted (higher risk of toxicity) Regulates expression of more than 100 genes. Retinoid acid: regulates cell differentiation, growth, and embryonic dev. Photosensitive cells contain rhodopsin (part vit. a) *important in sperm and fetal development, and bone remodeling. Antioxidant in the form of beta carotene. *de ciency is a problem in developing countries. can cause blindness, risk of infectious disease and death. *keratinization: change in shape and size of epithelial cells, skin becomes scaly, disrupts digestion and absorption of nutrients and weakens defenses. *toxicity: concern with supplements, children are most vulnerable, bone defects. Not an essential nutrient, body synthesizes it from sunlight and cholesterol. Two hydroxylation reactions in the liver and kidneys must occur. Active form of vitamin d is a hormone. Enhances calcium and phosphorous absorption (gi and kidneys). De ciency: relatively rare, but insuf ciency is common.
