How much is too much (b12)

I'm not a vegetarian, I don't eat red meat, but I do eat a lot of poultry (white chicken meat, eggs),yogurt, and cheese in moderation. I also take b12, and for the past year i've been taking about 1,000 mcg's a day and I was thinking of upping it to 2500 mcg's or even 5,000. I hear too much b12 can have adverse digestive effects etc etc, any answers would be helpful.

Had to do a little reading on B12 to make sure but... Are you sure you take 1,000mcg a day? Thats wicked un-healthy alone. The non-toxic amount a day is 100mcg a day and 100 mcg pr. day is actually a pretty high dose, unless you have a deficiency.  The recommended dose for a normal adult is much lower then 100mcg.

google the symptoms of too much b12 but pulled off a health forum:

More about B12/cobalt overload from http://www.acu-cell.com/nico.html :

"Even without having had any Vitamin B12 injections, individuals who run naturally high Vitamin B12 and cobalt levels (which may include patients with mitral valve prolapse), tend to frequently suffer from tachycardia, panic-anxiety attacks, or angina-like chest pains, that may be accompanied by numbness and tingling in the face or extremities

I'm positive I am, i take 2 500 mcg's a day, my doctor had nothing bad to say about it and there are no reports of b12 "overdoses" , i was just wondering if there are any long term adverse affects people have noticed

I was lacking B12 for awhile due to diet and man do you ever feel sick! But if you are eating chicken you probably don't need to be taking B12. You're body doesn't need very much of it. Also  many non-meat foods are fortified with B12 (like cheerios). Get a blood test if you are worried...if your levels are low you'll only need a few B12 shots....

You would get all the B12 you need from the animal products that you eat.  If you were a Vegan, you might need to add it, as the soil does not have as much as is did in the past.  Like others have stated, if you are worried you can be tested to make sure your body is using the B12 it gets.  I would not suggest taking a suppliment unless you needed it.

after looking this one up in one of my nutrition textbooks to answer your question there is no tolerable upper intake(the most you can consume/day) for b12 and no reported toxicity....but that being sad you are probably getting enough from your diet and it is ten times more beneficial to get the nutrients you need from food rather than supplements...

"good sources" listed were:

chicken liver 3oz=14.0mcg

sardines 3oz=7.5mcg

tuna 3oz-3.0mcg

swiss cheese 1.5oz=1.5mcg

pork roast(lean) 3oz-1.0mcg

cottage cheese 1 cup=2.0 mcg

But be aware that the DRI for adults is only 2.4 mcg/day so 1,000 mcg is A LOT...

hope this helps