Estrogen can cause major histamine release in the body. Now why would you want that? Because histamine makes you um, randy, and your biological imperative is to procreate. We shouldn’t really complain though,estrogen makes us more attractive to the opposite sex…but back to my point.

Studies on female rats show that estrogen supplementation, or natural fluctuations in cycle near ovulation, cause libido boosting histamine release. Didn’t know that histamine affects your sex drive? You’re welcome! Please explain to your significant other that spiking your meals with cashews isn’t necessary thank you very much. It’s one of the many perks/crosses to bear with our histaminosis/histamine intolerance diagnosis.

Estrogen is important in female precopulatory behaviors in 3 m ways: 1) estrogen increases a female’s willingness to approach a male to induce solicitatious behaviors, 2) estrogen can enhance the “attractivity” of the female: estrogen priming can induce the production of stimuli that make her more attractive to the male (odors or pheromones, vocalizations), and 3) estrogen ‘primes’ for progesterone.

So…

Histamine-induced responses shown in this study indicate a possible mechanism through which the generalized arousal factor (histamine) can affect neurons in a local brain area (VMH), which is crucial for a specific motivated behavior (lordosis). Furthermore, we addressed this question by examining whether a general arousal modulator, histamine, interacts with a hormonal modulator, estrogen, in VMH neurons. Our results are remarkable in the sense that they show a possible pivotal point where generalized arousal influences and supports a specific (sexual) arousal state. As a generalized arousal neurotransmitter, histamine’s excitatory impact on VMH neurons was further potentiated by estrogen. Thus the interaction between histamine and estrogen might be a key mechanism linking generalized arousal with specific (sexual) arousal. Read the full study here.

In plain English: this study showed that estrogen supplementation (or natural fluctuations) caused the neurotransmitter histamine be released, making female rats stick out their butts so males could mount them. Luckily as human beings we’re (mostly) able to control who mounts us!

This study explains a few things I noticed these last two years: that my symptoms fluctuate with the menstrual cycle (more on that in an upcoming post), that birth control pills made me lose my mind, but that there’s no way I could out crazy estrogen flushed high histamine pregnant friends!

The study went on to touch on my favourite subject: histamine as as weight loss and appetite control mechanism…

Histamine also modulated feeding behavior through its receptors in the VMH. As shown by Sakata (Sakata and Yoshimatsu 1995), food intake was suppressed and drinking was accelerated by either activation of H₁ receptors or inhibition of H₃receptors in the VMH. Pharmacological blockage of both H₁ and H₂ VMH receptors significantly increased overnight food intake and decreased water intake, which may be specifically attributed to the set of histaminergic receptors situated within the VMH (Magrani et al. 2004

Read the full study here.

And then of course you have the fact that histamine’s H1 receptor itself releases estrogen…