Is histamine the hidden cause behind your anxiety?

If you’ve ever suffered the annoyance of hayfever or hives you might be familiar with histamine by way of its nemeses - antihistamines. We often turn to these to help control the itching, swelling, redness and phlegm production triggered by things like pollen, dust, cats and certain foods.

We mostly think of histamine for its role in immune activation, raising the red flag when there is a perceived threat and calling for an inflammatory response to help the body deal with it. But histamine is so much more than that.

What many people don’t realise is that histamine has four different receptors around the body - H1, H2, H3 and H4 – which means it has a huge range of effects, from influencing stomach acid, blood vessel dilation, hormone release, temperature control, satiety, energy levels and most interestingly, your mental health.

Histamine As a Neurotransmitter

Histamine also works as a neurotransmitter, a chemical messenger which carries signals from one nerve cell to another. Nerve cells which produce histamine are exclusively made in the tuberomammillary nucleus within the hypothalamus, and from there project throughout the brain.  

Plus, histamine influences the release of other neurotransmitters such as serotonin, dopamine, noradrenaline and GABA. All of this is important because it means histamine is involved in a variety of nervous system functions including:

·      Learning

·      Cognition

·      Memory

·      Attention

·      Mood regulation

·      The stress response

·      Alertness

This helps explain why histamine has been linked to conditions such as narcolepsy, Alzheimer’s, ADHD, Parkinson’s, and schizophrenia.

One of histamine’s biggest roles is in the sleep-wake cycle. It stimulates alertness in line with circadian rhythms: production of histamine is increased when we are awake, reduced when we are relaxed and significantly less when sleeping. This is why some antihistamines make you drowsy – they block histamine attaching to the receptors which would normally cause alertness.

Histamine Intolerance: When the Bucket Overflows

As you can imagine, with such far-reaching and important effects, an imbalance of histamine doesn’t go unnoticed.

Histamine intolerance happens when the body can’t efficiently manage and clear the accumulated load of histamine – from allergies, internal production and ingestion through food.

The bucket analogy is handy to explain this: when histamine clearance is insufficient, the histamine builds up in a metaphorical bucket, which can overflow into symptoms. Due to the wide spread effects of histamine, symptoms can be all over the place:

·      Anxiety, depression, brain fog, difficulty concentrating

·      Insomnia, fatigue

·      Headaches, migraines, dizziness

·      Bloating, diarrhoea, reflux, nausea, abdominal cramps

·      Sinus congestion, sneezing, difficulty breathing

·      Hives, itchy skin, flushing, rashes

·      Heavy periods, painful periods

·      Postural hypotension

·      Joint pain, swelling

Histamine intolerance is also more common in women, thanks to the close relationship between oestrogen and histamine where they spur each other on: histamine triggers oestrogen production and high oestrogen stimulates histamine release. So, if you’ve noticed more headaches, insomnia, congestion or flushing when oestrogen is peaking around ovulation and before your period, histamine could be to blame.

How Allergies Can Tip the Histamine Balance

Every time you react to an allergen – pollen in spring, the cat next door, the food that makes you itchy – it triggers the release of more histamine, building up levels in the bucket.

At the same time, if the body struggles to keep up with the clearance of histamine, the bucket can overflow and seemingly out of nowhere the sneezing starts, the rash flares, anxiety spikes or digestive symptoms worsen. Inflammation also occurs, which further impacts other health conditions like depression, joint pain and period trouble.

Histamine, the Gut Microbiome and Your Mental Health

We’ve talked about histamine being produced by immune cells and also in the brain, but your gut microbiome plays its part too.  

1. Histamine-producing gut bacteria

Certain strains of bacteria in the gut produce more histamine than others, if you have more of these particular gut bugs, this can contribute to the overall load of histamine in your bucket. We can help reduce histamine-producing bacterial strains in the gut by consuming a variety of plant-based foods. This feeds a wide variety of beneficial bacteria and helps crowd out problematic ones.

2. DAO is made in your gut

Diamine oxidase (DAO) is a major enzyme involved in breaking down histamine that we eat. This enzyme is produced in the gut lining, so factors influencing gut integrity can also influence histamine balance - think irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), imbalances in gut bacteria (dysbiosis), food intolerances, infections and even stress.

3. Your gut makes neurotransmitters too

The gut microbiome also produces other neurotransmitters such as serotonin, GABA, acetylcholine and dopamine. Not all of these are able to cross the blood-brain barrier but they do act on the enteric nervous system of the gut - including the vagus nerve - and influence building blocks to produce neurotransmitters in the brain, like tryptophan for serotonin production.

This is just another reason why gut health and mental health are so intertwined, and why histamine imbalances can affect so many mental health symptoms.

How To Know If Histamine Might Be an Issue for You

As you can tell by now, histamine shows up all over the body, so it can be tricky to pinpoint. Here are some clues that histamine might be a problem:

·      You feel like you are reacting to every food, or fine with a food one day and not the next (when levels of histamine have accumulated).

·      High histamine foods make you feel worse. These include fermented foods & drinks (e.g. sauerkraut, kombucha, beer), hard cheeses, processed meats, alcohol, bone broth, chocolate, citrus, avocado, smoked and canned fish.

·      Symptoms are linked to your menstrual cycle

·      Antihistamines are helpful short term

Keeping a diet diary or trialling a low histamine diet for a few weeks can help provide some insights.

Does This Resonate?

If the symptoms described in this article sound like you, read the full article, including at-home tips for anxiety and how to address histamine imbalances with both Naturopathy and Positive Association Technique (PAT) on the Health & Wellness Australia & New Zealand blog.

Originally written by Leila DiQuinzio for Health & Wellness Australia & New Zealand on https://naturalallergytreatment.com.au