B12 and folic acid can worsen histamine symptoms by converting histamine into methylhistamine, a more potent form. If your MAO enzyme is low, methylhistamine accumulates and causes inflammation, insomnia, and manic-like symptoms. MAO also breaks down dopamine, norepinephrine, and estrogen.
Some people aggravate with histamine symptoms when you give them B12 or folic acid or a combo. The reason is, is that they methylate their histamine. It turns out that methylhistamine, which is an intermediate in this pathway, is— I call it evil histamine. It's the toxic form of histamine that binds tighter to histamine receptors. So if the person methylates their histamine, but then they can't get the methylhistamine through monoamine oxidase, which is very common, they build up this superactive histamine metabolite that creates inflammation, insomnia, mania. After monoamine oxidase, histamine aldehyde is an intermediate. Histamine aldehyde is literally a neurotoxin. Remember that dopamine, norepinephrine have to go through MAO. Histamine goes through MAO, but also estrogen metabolizes through MAO. Other hormonal things metabolize there. All 3 ways out important to support.
