By Naturopath Sam Botica
Especially at this time of year, I see people struggling with all kinds of symptoms that are often related to histamine levels. even though histamine is usually associated with hay fever and allergies, it actually has a few different roles in the body.
Histamine acts as a chemical messenger that is involved in immune responses, digestion, stomach acid production and the sleep/wake cycle.
Usually, histamine is produced by the body, used and then broken down without causing problems. But of course, things don’t always go to plan, and some people have recurring symptoms after eating certain (histamine-rich) foods or when multiple triggers start to build up.
This can be described as histamine intolerance or sensitivity to dietary histamine.
What is histamine intolerance and how is it different to an allergy?
Histamine intolerance is not the same as a food allergy.
A food allergy involves an immune response to a particular food protein. Histamine intolerance is thought to occur when the amount of histamine entering the digestive system exceeds the body’s ability to break it down effectively.
Possible symptoms can include:
- Headaches or migraines
- Flushing, itching or hives
- Nasal congestion or sneezing
- Bloating, abdominal discomfort or changes in bowel habits
- Dizziness
- Fatigue or difficulty concentrating
These symptoms are not specific to histamine intolerance and can occur with many other health conditions. There is also no single test that can conclusively diagnose it. That’s why careful and thorough assessment is important before assuming histamine is the cause and especially before starting any kind of highly restrictive diet.
So, what might contribute to histamine issues?
1. Reduced histamine breakdown
Diamine oxidase, or DAO, is an enzyme found mainly in the lining of the small intestine. One of its roles is to break down histamine from food before too much enters the bloodstream.
Some people may have reduced DAO activity due to genetic differences, changes affecting the intestinal lining or other individual factors. When histamine is not broken down efficiently, symptoms may be more likely after eating foods containing higher amounts.
However, low DAO is not always the complete explanation. Blood DAO testing alone cannot reliably confirm histamine intolerance, so results need to be considered alongside symptoms, medical history and other possible causes.
2. Gut health
Because much of the breakdown of dietary histamine happens in the digestive tract, gut health may form part of the picture.
Inflammation or damage affecting the intestinal lining may influence DAO activity. Research has also found differences in the gut bacteria of some people experiencing histamine-related symptoms. Certain bacteria can produce histamine, although we are still learning exactly how changes in the microbiome affect symptoms.
Its important to also consider conditions like coeliac disease, inflammatory bowel disease and other gastrointestinal disorders that can also produce similar symptoms or affect how foods are tolerated. These need to be properly investigated rather than attributed automatically to histamine.
3. Food and alcohol
Histamine occurs naturally in some foods and can increase as food ages, ferments or is stored.
Common higher-histamine foods include:
- Aged cheeses
- Processed or cured meats
- Fermented foods
- Wine and beer
- Some canned, smoked or poorly stored fish
Alcohol may be a problem for some people because it can contain histamine, encourage histamine release and interfere with its breakdown.
Individual tolerance varies considerably. One person may react to a particular food while another does not, and the same person’s tolerance may change depending on portion size and what else is happening in their health.
This is why simply following a long list of “forbidden foods” is not always the best approach.
4. Medications
Some medicines have been proposed as affecting histamine metabolism or DAO activity. These may include certain anti-inflammatory medicines, antibiotics, antidepressants and other prescription drugs.
The evidence and effects differ between individual medications. Never stop or change prescribed medicine because of suspected histamine intolerance without speaking to your doctor or pharmacist.
A practitioner can instead help you review the timing of your symptoms and discuss whether further medical advice is needed.
5. Allergies and environmental exposure
Allergies and histamine intolerance are different processes, but both involve histamine.
If you have a pollen, dust mite, mould or animal allergy, exposure can stimulate immune cells to release histamine. During Perth’s spring pollen season, this may contribute to symptoms such as sneezing, congestion, itchy eyes, coughing or wheezing.
This does not necessarily mean that you have histamine intolerance. However, existing allergies can add another layer to the symptom picture and may help explain why you feel more reactive at certain times of year.
6. Hormonal changes and stress
Some people report that their symptoms fluctuate across the menstrual cycle or during perimenopause. Laboratory research suggests there may be interactions between oestrogen, mast cells and histamine, but the clinical relationship is complex and still being investigated.
Stress can also affect digestion, sleep, food choices and the experience of symptoms. It may be one contributor, but it should not be presented as the sole cause of a physical reaction.
Why finding the cause can be difficult
Histamine-related symptoms can overlap with allergies, food intolerances, gastrointestinal conditions, migraine, hormonal changes and a range of other health concerns. In a naturopathic consultation, we will always look at the range of symptoms you’re experiencing, consider the range of factors that may be contributing and investigate underlying potential causes. It’s usually a much more comprehensive and holistic approach than may people are used to!
There is rarely one obvious cause. When people come to see me, what is more useful is to look for patterns:
- Which symptoms occur?
- When do they begin?
- Are they consistently connected with particular foods?
- Do portion size or food freshness matter?
- Do symptoms change with pollen exposure, alcohol, illness, medication or the menstrual cycle?
- What other conditions need to be ruled out?
A food and symptom diary can sometimes help reveal patterns. If a supervised lower-histamine diet is appropriate, it should generally be used as a short-term assessment tool followed by careful reintroduction, not as an unnecessarily restrictive lifelong diet.
Sam Botica is a naturopath with more than 25 years of clinical experience and a special interest in allergies, digestive health and immune-system reactivity.
Sam takes the time to look at the whole picture, including your symptoms, diet, digestive health, diagnosed conditions, medications, lifestyle and possible environmental triggers.
Rather than assuming every symptom is caused by histamine, the goal is to identify the factors most relevant to you and develop a practical, personalised plan. Where symptoms suggest an allergy or another medical condition, appropriate medical assessment remains important.
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