B12 & Folate Flashcards
Vitamin B12 refers to a family of what
cobalamin compounds containing cobalt in the centre
B12 i found only in foods of what origin?
animal origin
5 food sources B12
meat (esp organ)
fish
eggs
milk & cheese
which food sources do vegans think contain enough vitamin B12 to meet their needs?
algea (spirulina)
miso etc
why are plant sources of vitamin B12 no use to us?
B12 in those products occurs mainly as inactive analogs and are not utilised by humans
what should all vegans supplement with
B12 - or fortified foods with active analogs
how is B12 affected by cooking?
as bound to protein, 70% activity is retained
how can B12 be lost in milk
when pasteurised or evaporated
as B12 bound to protein it is released by what digestion
pepsin digestion in stomach
which is the specific B12 binding protein produced in the stomach
Instrinsic factor
where is IF-vit B12 complex absorbed
small intestine
where is it B12 stored
mainly in liver
which type of circulation contributes to B12 stores in the liver
enterohepatic circulation
which 2 processes in the body does B12 facilitate
metabolism of folic acid
synthesis of DNA
B12 function in which 2 enzyme forms
adenosylcobalamin
methylcobalamin
adenosylcobaliamin & methylcobalamin play an essential role in the metabolsim of
all cells
especially GI tract, bone marrow, nervous tissue
hyperhomocysteinaemia is what
high serum concentrations of homocysteine
high serum levels of homocysteine lead to what
cardiovascular events
taking what can reduce hyperhomocysteinaemia
B12, B9 & B6
what else does a patient with hyperhomocysteinaemia need to do, besides supplementation, in order to reduce the risk of cardiovascular events
lifestyle change
who else should supplement with B12
Elderly adults - 25-37.5 mcg/day
vegans 1-25mcg/day
which other conditions have increased B12requirements
pregnancy
thyrotoxosis
malignancy
liver & kidney disease
