NFS284H1 Lecture Notes - Lecture 18: Vitamin Deficiency, Keratin, Xerophthalmia
7 Apr 2018
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Why is vitamin a the most common vitamin deficiency: not found across the food supply. Is there vitamin a in fast food: very little in the cheese. What preformed vitamin a is found in animal foods: retinol, can be converted to retinal -> retinoic acid. What vitamin a is found in plant foods: beta-carotene, can be converted to retinal -> retinoic acid, not efficient, antioxidant. How much beta-carotene required for 1ug rae: 12ug. Does increased beta-carotene consumption reduce lung cancer risk: no, it increases it. What happens when you eat too much beta-carotene: hypercarotenemia. What does vitamin a decency cause: night blindness. What does a flash of bright light do: wipe out cis-retinal. Is vitamin a (retinoic acid) involved in gene expression: yes, it"s a ligand to a transcription factor. What does vitamin a deficiency do in regards to epithelial cells: prevention of mucus production, production of keratin (hard and dry) -> increase risk of infection, xerophthalmia - dry eyes.
