Is your anti-histamine making you fat?

In last week’s post “Histamine’s upside: I lost 35kgs in 6 months” I mentioned the role of histamine in appetite suppression. I recently had a  conversation with a friend whose family member suffers from anorexia nervosa. I felt compelled to share that in my teens I too was thought to be anorexic. Food was hurting me so badly that I was starving myself to make it stop. It was more than just a physical reaction, because as we know, histamine is a neurotransmitter and as such affects mood. Food made me crazy, depressed, anxious and manic but I had no clue what was causing it all, despite my raging allergy symptoms.I’ve spent the last few days doing some more research into what’s behind my suddenly stable weight these last two years:H1 receptor antagonists like loratidine (claritin) and cetirizine (zyrtec) make you fat. It’s just a fact. It’s in the medical inserts of both and my own personal hellish experience on them confirms it. At my worst, when I was taking one and a half to two pills daily, I became obsessive about food – to the point of dreaming about eating. I would get up several times a night to rummage through the fridge and spend almost the entire day absolutely ravenous. I would graze all day long. The most incredible benefit of having stopped them is the relief from my food fantasies. I can now easily go half a day without once thinking about food. Is that abnormal? Seems I have H3 receptor stimulation to thank for it. Studies show that H3 receptor agonists (the opposite of antagonists like Claritin and Zyrtec) suppress appetite.


The H3 receptor is a pre-synaptic autoreceptor that inhibits the synthesis and release of histamine, and a heteroreceptor that inhibits other neurotransmitters such as serotonin (5-HT), noradrenaline (NA) and acetylcholine (ACh), which are also implicated in the regulation of food intake. Thus, the H3 receptor is in a prime position to regulate food intake, both through its control of histamine and its influence on other feeding pathways.Study

Translated into English: as a neurotransmitter, histamine affects the brain chemicals that control hunger!

Not just that, but the studies go on to say that histamine’s H3 receptor plays a part in how our body burns fat and what temperature your body runs at. I know from experience that my body runs very very hot when I’m in histamine overload. Interestingly I did some research into a diet pill I looked into in my teens – it worked by raising your body temperature.

Nowadays I don’t take any antihistamines, choosing instead to control my histamine level through diet (check out my low fat high nutrient low histamine DAO Support Cookbook) and a great quercetin supplement called Neuroprotek.

Next step would be finding out if certain foods affect just one of the histamine receptors, H3 in particular, in order to lose weight. Don’t worry, I’m on the case. Sign up to my newsletter for more info on this subject and others.


Check out these other Healing Histamine blog posts


Yasmina was an award-winning broadcast journalist with a decade of experience covering war zones for CNN and the BBC. She devoted her journalism skills to researching and writing about histamine. Click here to learn about her. Each post is carefully and fully referenced with the latest scientific research. Not sure where to start? Here’s a four week meal plan and overall Histamine Reset.

4 Week Histamine Reset

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