Vitamin MetabolismVitamin Metabolism

Robert F. Waters, PhDRobert F. Waters, PhD

Basic ChartBasic Chart

Vitamins Continued:Vitamins Continued:

Vitamins Continued:Vitamins Continued:

ThiaminThiamin• In all cells including brainIn all cells including brain• Tpp-active formTpp-active form• HMP, PDH, TCAHMP, PDH, TCA• Absorption by active transport and diffusionAbsorption by active transport and diffusion• Not storedNot stored• ToxicityToxicity

– None reportedNone reported• Deficiency Deficiency

– Mainly associated with alcoholismMainly associated with alcoholism– BeriberiBeriberi

• Peripheral neuropathy especially frequently used limbsPeripheral neuropathy especially frequently used limbs• Thiaminases (Lower Thiamin Availability)Thiaminases (Lower Thiamin Availability)

– In raw fish (sushi), shellfishIn raw fish (sushi), shellfish– Tannins, factors in tea and coffeeTannins, factors in tea and coffee

RiboflavinRiboflavin• Lack causes pellagra (Same for lack of niacin)Lack causes pellagra (Same for lack of niacin)

– Dermatitis (Esp. nose and scrotum)Dermatitis (Esp. nose and scrotum)– Vascularization of corneaVascularization of cornea– Magenta tongueMagenta tongue

• Stronger oxidizing agents than NAD thus in ETS type systems.Stronger oxidizing agents than NAD thus in ETS type systems.– Two oxygens may be attached when in reduced formTwo oxygens may be attached when in reduced form

• Active forms are FAD and FMNActive forms are FAD and FMN• Toxicity (Very low)Toxicity (Very low)• Absorption Absorption

– Upper small intestine by active transportUpper small intestine by active transport• Not storedNot stored• IN; ETS, FAS, FAO, MAO, Xanthine Oxidase, Glutathione IN; ETS, FAS, FAO, MAO, Xanthine Oxidase, Glutathione

Reductase (RBC)Reductase (RBC)

Riboflavin Continued:Riboflavin Continued:

• Stimulated by T3 (Thyronine)Stimulated by T3 (Thyronine)