Histamine intolerance symptoms include anxiety, insomnia, heart palpitations, shortness of breath, nausea, sweating.
Histamine is commonly known for its role in allergic reactions, but histamine also functions as a neurotransmitter in the brain.
It’s involved in learning, memory, attention and alertness. It also promotes the release of adrenalin and noradrenalin (stress hormones).
Histamine in the brain
The brain produces its own histamine.
Histamine in the body does not cross the blood brain barrier.
Histamine is degraded in the brain by methylation via the Histamine-N-Methyl-transferase (HNMT) enzyme and via the MAO-B enzyme.
What increases histamine in the brain?
- A genetic mutation on either the HNMT or MAO-B enzymes can cause histamine build up in the brain.
- Oestrogen increases histamine in the brain as it crosses the blood brain barrier. It’s important to know that histamine produced in the body stimulates the ovaries to produce more oestrogen. This increase in oestrogen will then increase histamine in the brain. This shows a clear link between histamine in the body and histamine in the brain, which is very important for how we treat histamine related anxiety.
How does histamine trigger anxiety?
Increased levels of histamine disrupt the sleep-wake cycle in the brain causing insomnia, which is a significant contributor to anxiety in many people.
We see this a lot clinically with women during the times of their menstrual cycle where oestrogen is at its peak at ovulation and then again premenstrually when progesterone drops, leaving oestrogen unopposed.
Histamine also promotes the release of adrenalin and noradrenalin from the adrenal glands. An increase in these hormones cause many of the physical symptoms of anxiety including heart palpitations, shortness of breath, sweating, shaking and nausea.
Steps you can take to reduce histamine related anxiety
- The first step is to look at any blockages in your ability to make SAM. A key enzyme involved in making SAM is MTHFR. If you have a genetic mutation on MTHFR you may have a reduction in functioning of that enzyme which will need support. You can read more about MTHRF and methylation here
- Vitamin B12 is another essential nutrient required to make SAM. To ensure you have good amounts of Vitamin B12 you need to be consuming animal protein regularly or supplementing with Vitamin B12. To absorb Vitamin B12 you need adequate amounts of hydrochloric acid in the stomach and a healthy gut microbiome, so correcting any gut issues is essential.
- Other key nutrients required from making SAM are B Group vitamins, zinc, choline and methionine. Vitamin B2 is also need as the cofactor for MOA-B.
- Reduce the load of histamine in the body. There are many foods that are high in histamine that you can reduce in your diet. Fermented foods, aged cheeses, cured meats, tinned fish, tomato, avocado, alcohol are all particularly high in histamine.
- SIBO and dysbiosis in the large bowel increase the histamine load in the body. If you have any gut issues these need to be treated as a priority.
- Reduce the amount of oestrogen via supporting the detoxification of oestrogen via the liver. Phase II liver detoxification of oestrogen relies heavily on methylation, so again we need to make sure we are supporting the production of SAM.
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Hass HL, Sergeeva OA & Selbach O, 2008, ‘Histamine in the nervous system’ Physiological Reviews’, vol. 88, no 3, pp 1183-124
Hu W & Chen Z, ‘The roles of histamine and its receptor ligands in central nervous system disorders: An update’, Pharmacology & Therapeutics, vol 175, pp.116-132