What people call "having a life" can really disrupt one's train of thought. ;-) I was chugging right along on the subject of histamine/tyramine when a distraction or two caused me to lose control of the mental plates i was juggling and CRASH -- the shards of ideas lying around my feet are quite a mess i need to clean up!
The short version is, when our bodies can't process properly what we put into them, repercussions spread far and wide. Anything that hints to our bodies that things aren't going well causes stress hormones to rise and thyroid levels to fall. Such simple things as too much exercise or glucose-yielding foods, environmental mold, extremes in temperature, and foods for which we don't reliably produce the right breakdown enzymes can set off a cascade of different symptoms.
To be fair, it's not surprising that doctors don't know how to diagnose a lot of the illnesses they see until they have a good deal of experience -- especially considering how many textbooks seem to be written by purveyors of pharmaceuticals, disease seems to be a kind of drug-deficiency to a lot of people. The old days of young medicos going into practice with old-timers, thus having a sort of in-the-field apprenticeship, would appear to be over; doing apprenticeships in hospitals (as interns and residents) where illness is more of an acute situation wouldn't seem as sound a background for someone with an eye to General Practice. Because of the current system, we end up with excellence in dealing with trauma and we totally suck at promoting actual WELLNESS. If the difficulty can't be sewn up, cut out or killed with antibiotics, or if the dis-ease is too subtle or generalized, the medical industry doesn't know what to do with it.
And wellness is exactly what a lot of us want to be pursuing, in the paleo/primal/WAPF blogosphere! This is why those of us whose difficulties can't be sewn up, etc., have turned into renegades and iconoclasts and have turned our backs on the mainstream medicine which is not interested in our goal.
If we want to be as healthy as possible, we HAVE to define what's best for us, usually by trial and error. Then when that line is defined, we have to toe it to the best of our ability, realizing that every excursion from it causes pain and suffering commensurate with how far out of bounds we have let ourselves go. Some can have the occasional "fling" with nutritional good-for-nothings and experience minimal repercussions, while others flirt with anaphylaxis merely by light exposure to some substances. Some can have a "forbidden" treat occasionally, and others find one cookie can put them on the slippery slope. It's all highly individual.
Having become alerted to how bad high-histamine foods can make me feel and the range of possible symptoms, i've started to notice histamine-related responses more. This is a good thing! Like other kinds of allergy, these responses are cumulative. Balancing range-of-tolerance of foods with environmental conditions can make a huge difference to daily quality of life.
Robust thyroid function allows for the kind of energy that makes life worth living, and thyroid function can be tweaked hugely with diet. ENOUGH of the foods which are good for the thyroid, like animal protein, and saturated and O3 fats, helps immensely, and excessive calorie-restriction is guaranteed to reduce production. MINIMIZING what inhibits and puts excessive demand on our systems is equally important -- contrary to what euthryroid athletes believe, carbohydrates require more hormone to process and so put a strain on our resources. Omega-6 fats make it difficult to get thyroid into our cells for use, and MUST be strictly limited. Our digestive inadequacies make it doubtful that we can properly absorb or convert the critical nutrients we HAVE to acquire, and some kinds of supplementation can be mandatory.
Not only are grains and legumes problematic by way of the gut-damaging lectins they contain, but they also carry a large histamine load. Large histamine load EQUALS stress, and stress causes us to produce, convert and use thyroid hormones in a less-than-optimal way. Looking at the list of symptoms suffered by the histamine/tyramine-sensitive is almost a mirror of those experienced by the thyroid-challenged among us.
Tyramine is a breakdown product of tyrosine, which is the building-block of thyroid hormone (along with iodine) -- this was the point in my research where i was interrupted, and where i need to start regathering the tangled threads of ideas i was weaving. When meat and fish have been processed for preservation (or simply kept around too long), some of the health-giving amino acid gets too far gone -- past tyrosine and into the irritating tyramine which behaves like those nasty histamines, setting off the alarms in our bodies which are so uncomfortable. I strongly suspect that a lot of thyroid malfunction (both hypO and hypER) is inextricably entangled with this process.