Lecture-38 - Vitamins A diverse group of organic compounds...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Vitamins A diverse group of organic compounds that either cannot be synthesized at all by the body, or synthesized in sufficient amounts to maintain normal tissue function. Thirteen vitamins have been identified in humans. Vitamins are categorized as either water-soluble (vitamin C and the B vitamins) or fat-soluble (vitamins A, D, E and K).
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Laetrile (B17) Pangamic acid (B15) Orotic acid (B13) Gerovital (H3) bioflavinoids Some compounds normally synthesized by the body may be “ conditionally essential ” under conditions such as prematurity, genetic aberrations or parenteral feeding. These include choline and carnitine . There is no evidence that the following compounds are really vitamins: Two vitamins have precursor forms that are metabolized to the active form of the vitamin: vitamin A ( β -carotene) and niacin (tryptophan).
Background image of page 2
Types of Vitamin Deficiencies 1. Primary – due to inadequate intake 2. Secondary – malabsorption, drug-nutrient interactions, increased vitamin needs due to stress or disease. Inadequate intake in western society it’s usually seen in (1) individuals undergoing drastic dieting; (2) the poor and destitute; (3) those whose lifestyles predispose them to vitamin deficiencies (eg., “bachelor’s scurvy”); (4) those restricting their diets for philosophical/religious reasons; and (5) weaning practices in some cultures. Drug-nutrient interactions – many therapeutic agents interfere in vitamin absorption ( neomycin affects B12 absorption). Excessive alcohol, caffeine and nicotine intake can interfere with vitamin metabolism.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
During growth, pregnancy/lactation, and in postsurgical, burn and trauma patients as well as those with some diseases. In pregnant women, administration of folate above recommended daily intake levels reduces incidence of neural tube defects. Some vitamins (egs., A, E, C) may decrease risk of getting some cancers (anti-oxidant effects). Should I partake of megavitamin therapy? For water-soluble vitamins , you’ll excrete the excess vitamins taken in; tissue levels will not rise. Niacin (B3) and pyridoxine (B6) can produce some toxicity. Among the fat-soluble vitamins, vitamins A & D can produce toxicity. At this time megavitamin therapy is not a scientifically accepted
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/27/2009 for the course BIO 51310 taught by Professor Sisson during the Spring '08 term at University of Texas at Austin.

Page1 / 14

Lecture-38 - Vitamins A diverse group of organic compounds...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online