Biochem - Nutrition (Part 2: Vitamins B9, B12, C, & D) Flashcards
See p. 94-95 in First Aid 2014 Sections include: -Vitamin B9 (folic acid) -Vitamin B12 (cobalamin) -Vitamin C (ascorbic acid) -Vitamin D
What is another name for Vitamin B9?
Vitamin B9 (folic acid)
To what is Vitamin B9 (folic acid) converted? For what kind of reactions is this a coenzyme?
Converted to tetrahydrofolate (THF), a coenzyme for 1-carbon transfer/methylation reactions.
For what process(es) is Vitamin B9 (folic acid) important?
Important for the synthesis of nitrogenous bases in DNA and RNA
What is a source of Vitamin B9 (folic acid)? Where is it absorbed?
Found in leafy green vegetables. Absorbed in jejunum. Think: “FOLate from FOLiage”
Describe the body’s Vitamin B9 (folic acid) reserve pool and its location.
Small reserve pool stored primarily in the liver
What 3 physical/histological signs/symptoms result from Vitamin B9 (folic acid) deficiency? What key sign/symptom is lacking, and what clinical significance does this have?
Macrocytic, megaloblastic anemia; hypersegmented polymorphonuclear cells (PMNs); glossitis; no neurologic symptoms (as opposed to vitamin B12 deficiency).
What are 2 lab findings associated with Vitamin B9 (folic acid) deficiency?
Labs: Increased homocysteine, normal methylmalonic acid (unlike Vitamin B12, which has increased homocysteine and methylmalonic acid levels)
What is the most common vitamin deficiency in the United States?
Vitamin B9 (folic acid)
What are 2 conditions in which Vitamin B9 (folic acid) deficiency is seen?
Seen in alcoholism and pregnancy
What are 3 drugs that can cause Vitamin B9 (folic acid) deficiency?
Deficiency can be caused by several drugs (e.g., phenytoin, sulfonamides, methotrexate).
Why is supplemental maternal folic acid given early in pregnancy?
Supplemental maternal folic acid in early pregnancy decreases risk of neural tube defects
What is the function of Vitamin B12 (cobalamin)?
Cofactor for homocysteine methyltransferase (transfers CH3 groups as methylcobalamin) and methylmalonyl-CoA mutase
What 3 physical/histological signs/symptoms result from Vitamin B12 (cobalamin) deficiency?
Macrocytic, megaloblastic anemia; hypersegmented PMNs; paresthesias, and subacute combined degeneration (degeneration of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts) due to abnormal myelin
What are 2 lab findings associated with Vitamin B12 (cobalamin) deficiency?
Associated within increased serum homocysteine and methylmalonic acid levels.
What are the neurological findings associated with Vitamin B12 (cobalamin) deficiency, and what causes them?
Paresthesias, and subacute combined degeneration (degeneration of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts) due to abnormal myelin
What can result from prolonged Vitamin B12 (cobalamin) deficiency?
Prolonged deficiency => irreversible nerve damage