Folate Deficiency

[Shuparman]

Hello, I had a question regarding folate deficiency. I thought folate comes from green leafy vegetables, and that's what you weren't eating if you had a folate deficiency. However, I came across a qbank question that said the correct answer was "overcooked food". I was wondering if this is the better answer than "lack of leafy green vegetables". Thank you.

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[Wrigleyville]

Folate is in lots of stuff. Green vegetables, grains, beer, etc. Cooking can destroy it, so both of those answers are correct, but you have to be pretty bad off to get folate deficiency. Other correct answers include:

1) Phenytoin use-- phenytoin blocks intestinal conversion of folate to an absorbable form.
2) B12 deficiency-- You need B12 to convert folate to THF, which is why B12 deficiency causes symptoms of folate deficiency (megaloblastic anemia). Loading someone who is B12 deficient up on folate will correct the anemia, but not the neurologic signs (which are due to propionate buildup).
3) Methotrexate treatment.

 

[Shuparman]

Thank you for the reply. The thing of it is, both answers were choices on that particular question. But if folate is in a lot of food products, I guess just not eating green leafy vegetables wouldn't give you folate deficiency. Overcooking foods is probably more common.

 

[HiddenTruth]

Folate is in lots of stuff. Green vegetables, grains, beer, etc. Cooking can destroy it, so both of those answers are correct, but you have to be pretty bad off to get folate deficiency. Other correct answers include:

1) Phenytoin use-- phenytoin blocks intestinal conversion of folate to an absorbable form.
2) B12 deficiency-- You need B12 to convert folate to THF, which is why B12 deficiency causes symptoms of folate deficiency (megaloblastic anemia). Loading someone who is B12 deficient up on folate will correct the anemia, but not the neurologic signs (which are due to propionate buildup).
3) Methotrexate treatment.

i think FA says that u can also get B12 defic with phenytoin--do you know the mechanism of this?

 

[Wrigleyville]

i think FA says that u can also get B12 defic with phenytoin--do you know the mechanism of this?

I'm afraid I don't know that... the only things I can think of for B12 are pernicious anemia, fish tapeworm and crohn's if their terminal illeum has been resected.

There is something in lippincott's about phenytoin -- it says it interferes w/ B12, but I can't find anything about the mechanism. It doesn't say anything about phenytoin and folate though, which is strange.

 

[omarsaleh66]

Ok i learned this last week while listening to Goljan, and I already forgot it; so someone please correct me. There is an enzyme or a carrier or soemthing in the GI tract that is needed for folate absorption. chronic phenytoin use messes with that enzyme or carrier so u get folate deficiency. I think in these cases u have to increase folate dose to offset the phenytoin.

later

 

[HiddenTruth]

Ok i learned this last week while listening to Goljan, and I already forgot it; so someone please correct me. There is an enzyme or a carrier or soemthing in the GI tract that is needed for folate absorption. chronic phenytoin use messes with that enzyme or carrier so u get folate deficiency. I think in these cases u have to increase folate dose to offset the phenytoin.

later

yea, you are talking about intestinal conjugase, which is used to convert polyglutamate (the dietary form of folate) to monoglutamate, the absorbable form. And phenytoin inhibits intestinal conjugase. But, somehow, phenytoin is involved in b12 defic--i'll check some other sources for the mech.

Wrigleyville: Also, chronic pancreatitis can cause B12 defic (no proteases to to take the R binder off of the B12, so it can't be absorbed) and intestinal loop syndrome, or anything that promotes an envt for increased bacterial growth, i.e anything that impairs peristalsis (diabetic autonomic neuropathy).