B12 & Folate Flashcards
folate and B12 important in synthesis of …
DNA in RBC
haemotological presentations of vitamin B12 and folate deficiencies are …
almost identical
clinical difference is that B12 causes ____ whereas folate does not
neuropathy
what are vitamins?
micronutrients essential for health which cannot be made in the body so must be acquired from food or supplemets
two types of vitamin
- nine water soluble vitamins
- four fat soluble vitamins
vitamins Bs & Cs
- excess excreted in urine
- not stored except B9,12
- deficiency can occur
- easily absorbed from diet
vitamins DAKE
- not excreted in urine
- stored in fat
- unlikely to have deficiency
- can be toxic
- absoption depends on gut and pancreas
sources of B12
- cheese
- eggs
- fish
- beef
- yoghurt
B12 often called
Cobalamin
daily requirement of B12
1 - 2 micrograms
daily requirement of B12 for pregnancy
3 - 4 micrograms
half life of B12 when stored in liver
12 months
main loss of B12 from the body is via …
bile ( although half of it can be reabsorbed )
medicines that can interfere with absorption, metabolism of storage of B12
- H2 blockers
- neomycin
- metformin
abosrption of B12
- B12 attached to animal protein
- cut and chewed by teeth + mixed with saliva
- salvia contains R-binder that protects B12 from acids
- pepsin seperates B12 from meat + then binds to R-binder
- pancreatic proteases seperate B12 from R-binder then binds to IF
- in blood of portal vein 20% B12 combines with transcobalamin 2 and goes to body tissues
- IF receptors on apical surface of ileal cells collect IF &B12 and bring into cells
- remaining B12 circulates with transcobalamin 1 - not available to body cells
B12 signs & symptoms - haemotological
anaemia ( macrocytic )
B12 signs & symptoms - neurological ( periph )
- parathesia
- muscle weakness
- loss of proprioception
- headache
B12 signs & symptoms - neurological ( central )
- poor memory
- dementia
- depression
B12 signs & symptoms - physiological
- smooth tongue
- weight loss
- reduced apetite
folate refers to all forms of …
folic acid
folate is a substrate for…
thymidine
which vitamin is folate?
B9
folate abundant in what foods
- leafy greens
- liver
- kidney
- yeast
daily requirement of folate
100 - 200 mg
folate - jejunum
50% absorbed in upper jejunum
folate lost in -
- urine
- bile
- desquamating skin & intestines
folate deficiency can cause
- spina bifida
- neural tube defects
functions of folate
- helps tissues grow
- helps form red blood cells
- helps produce DNA
- works with B12 + vitamin C to help body break down, use and create new proteins
causes of folate deficiency
- alcohol
- haemolytic diseases
- malabsorption
- anticonvulsant medicines
- B12 deficiency
why should B12 deficiency be corrected before starting folate treatment?
because B12 deficiency can cause irreversible neurological disease
