Interesting. It seems that progesterone may increase the release of diamine oxidase in pregnant women. Why is this interesting?
Diamine oxidase is also known as histaminase and deactivates histamine in the intestines and kidneys.
In one of Dr Selwyn Dexter's cases, the patient was spontaneously cured during his wife's pregnancy with symptoms worsening after she gave birth. Dexter thought progesterone may be the reason and he gave the patient a small amount of progesterone. He was unsure why it worked however.
I have an idea. Perhaps the progesterone stimulated an increase in the levels of DAO in the patients intestines, thus reducing histamine levels.
Women with DAO synthesis deficits may have problems during pregnancy and it may lead to miscarriage, from the papers I've read. While DAO imbalance may be due to bacterial infection, it may also be due to a genetic problems in synthesising DAO or its consituents. THerefore, it's possible that POIS suffers may have an above average number of miscarriages in their extended family.
High histamine, increases estadiol levels and, therefore, may create hormone imbalance in males.
Increasing methylation may still solve the problem but it could be part of a joint approach involving increasing DAO or taking synthetic DAO to reduce gastric histamine levels.
Why do I favour methylation? Because histamine in the brain isn't cleared by DAO and because (from
http://ajcn.nutrition.org/content/85/5/1185.full)
HNMT has a slightly higher affinity for histamine [Michaelis-Menten constant (kM): 6?13 μmol/L] than does DAO (kM: 20 μmol/L)
Also from the same paper
In migraine patients, plasma histamine concentrations have been shown to be elevated both during headache attacks and during symptom-free periods. An increase in the number of brain mast cells is associated with pathologic conditions such as migraine, cluster headache, and multiple sclerosis (64).
However, if your POIS symptoms involve irritable bowel syndrome then supplementary DAO may bring some relief. Olive oil also promotes DAO synthesis apparently.
So, I think that I understand why the b complex doesn't work for everybody. I took it either with ginkgo (which contains a mast cell stabiliser) or methionine (which assists histamine methylation). Taken by itself without either of these some of the b vitamins may increase DAO (and reduce histamine) and others (like folic acid) may actually increase histamine levels.
If you're taking methionine with the b complex and it's still not improving things, I'm not sure what's happening.