Sensitivity to histamine is a little known and under-diagnosed problem, and my understanding of it has always been sketchy.
I know histamine is present in the body, as it’s essential to some of its many processes. I know it is released by immune system cells in response to allergens – a major cause of the symptoms those with allergies experience when exposed to their triggers. I know it’s found naturally in a lot of tasty or piquant foods – such as mature cheeses, yeast spreads, salami and fish. And I know that those with histamine intolerance often have to rely on strict diet modification, combined with supplementation with the enzyme DAO – which breaks down excess histamine in the body – in order to stay well.
Beyond that, I struggle. So the release of The Beginner’s Guide to Histamine Intolerance by one of the world’s leading experts in the subject, Dr Janice Joneja, is good news. It may be aimed at those who have or believe they have histamine intolerance, but it’s extremely useful to those who merely want a readable and well-written primer on the subject too.
The first surprise is that diagnosis, if it can be called that, is one of exclusion, in part. If certain conditions – allergy, autoimmune, mast cell disorders – have been ruled out by doctors, and a histamine-restricted diet resolves symptoms, sensitivity to histamine can be assumed.
There is similarity here with the diagnosis of Irritable Bowel Syndrome, which while far more well-defined a process, is also characterised by excluding certain diseases – such as coeliac disease. Throughout the book, Joneja uses a ‘full bucket’ analogy: keep your histamine levels below the rim, and you’re fine; but if they overflow, an ensuing mess of symptoms results – much like a FODMAP-aware diet in IBS. And the parallels don’t end there, as a lack of enzymes may be implicated in both: DAO and HNMT in histamine intolerance; disaccharidases such as lactose in IBS.
Much as the low-FODMAP diet is difficult and complex, so is the histamine-restricted one, we learn. Joneja advises consulting a registered dietitian before embarking on it, but I can’t help wondering how many RDs understand histamine sensitivity or deal with it in their practice. It is not yet fully accepted by orthodox medicine, after all. The excluded foods can be unusual and specific – bleached flour but not unbleached, red tomatoes not green, red beans not white, pumpkin seeds not other seeds – and it cannot be straightforward to formulate a diet which a patient is happy with, and confident she can stick to.
Joneja broaches IBS later in the book, arguing that IBS symptoms may lead to excess histamine, therefore in treating any co-existing IBS with lifestyle changes, histamine levels can be lowered by default. I did wonder, reading this, whether some lower histamine diets might also be coincidentally lower FODMAP, and therefore whether histamine intolerance can potentially be misdiagnosed in place of IBS.
A diverse and lengthy selection of case studies / Q&As wrap up the book. There’s a useful appendix on medications which can affect histamine levels in the body. I would have liked some recipe suggestions, to support those thrown in at the deep end with the diet – as the ‘safe to eat’ foods very often look considerably less flavoursome than the ‘avoid’ ones – but perhaps that’s one for the future.
For now, this is an indispensable introduction to a condition which may, the author believes, affect as many as 1% of the population. Could you be one of them?