Lecture 14 Water-Soluble Vitamins

Lecture 14 Water-Soluble Vitamins - Lecture 14....

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Lecture 14. Water-Soluble Vitamins •Why do we need to eat Vitamins? √ Lack ability to make essential chemicals √ Prevent deficiency √ Prevent birth defects / prevent disease -we need vitamins from food cuase we can’t make them -Improve Health? Slow Aging??? -Should we treat the symptom: “low vitamin status”?—extra supplement?--> “eat food instead!” -Or treat the underlying cause: the need for a complete diet?? •Absorption of Vitamins -go to intestine cells -water soluble serving as coenzymes to make regular enzymes work; rarely stored -fat soluble hormones; tend to be stored in tobdy •Loss of Vitamins during Food Preparation—cook with less water to not let the vitamins reach out to the water -Exposure to oxygen, heat or light -Leach out into cooking water -Milling of grains ex. white rice -Grain/cereal products enriched with: Folate, Thiamin, Riboflavin, Niacin, Iron -Still lack Fiber, trace minerals
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•Vitamins act as Cofactors (coenzymes) for enzymes 1. vitamin binding to a chemical group 2. coenzyme binding to an incomplete enzyme to make active enzyme -limiting factor= how much enzyme/ not how much vitamins -extra vitamins don’t make extra enzymes •Role of Vitamins in Energy Metabolism -every reaction requires some kind of vitamin cofactor •Folate—Folic Acid -Function: Synthesis of DNA, RNA, amino acids Converts Vitamin B12 to active form -Growth DNA synthesis required for cell division and duplication/ RNA can’t send messages protein synthesis -Food sources: foliage (traditional), green vegetables, grains, legumes, FORTIFIED breads and cereals •Folate Deficiency lack of cell division & disruption of B12 metabolism •Megaloblastic anemia • Spina Bifida • GI tract deterioration--> typical after taking cancer drugs; mucosal lining cells turnover really rapidly • Anti-folates (kemo) given as cancer drugs : inhibit cancer cell growth also stop other cell division Ex. losing hair Ex,.Methotrexate: stops cell division/ inhibit the folic acid pathway 1. Megaloblastic anemia not efficient in carrying oxygen; don’t lose nuclei -precursor in bone marrow can’t divide; have DNA in them -giving folic acid supplement to megaloblastic anemia? it won’t help if it’s iron deficient; vitamin K deficient; mercury poisoning folate only helps only megaloblastic anemia ex. giving iron to folate-deficient people will only make them sick treatment is very specific 2. Spina Bifida: incomplete closure of neural tube -embryonic rolling -anencephaly- doesn’t have brain -can lead to permanent paralysis; severe disability -rationale for fortifying grain with folate all people can get enough folate prevent spina bifida which happens from 21 days to 28 days
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•Vitamin B12 *Function: -Folate metabolism -Formation of myelin sheath *Absorption -Stomach: secretes Intrinsic Factor require stomach acid and pepsin -Intestine: B12- Intrinsic Factor Complex absorbed *Food sources: Animal products, B12 synthesized ONLY by bacteria(no molds, animals)
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This note was uploaded on 10/28/2010 for the course NST 114 taught by Professor Cassida during the Fall '10 term at University of California, Berkeley.

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Lecture 14 Water-Soluble Vitamins - Lecture 14....

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