If you’ve been experiencing unexplained symptoms such as an upset stomach, headache, or a runny or stuffy nose, you may have wondered if you have a histamine intolerance.
It can be hard to recognise because symptoms can come and go, and may seem linked with food, alcohol, stress or hormone changes. Read on to learn more about histamine, histamine intolerance and when to seek help.
What is histamine?
Histamine is a natural chemical that is made by your body. It is best known for its role in allergic reactions, but it also helps with body functions such as immune responses, digestion, sleep and brain function.
Histamine acts as a chemical messenger in your brain. It helps regulate sleep and wakefulness, mood, concentration, memory and thinking. In your digestive system, histamine helps tigger the release of stomach acid, which is needed to break down food and absorb nutrients. It supports your immune system by helping your body respond to injury, infection and allergens. Histamine also influences blood vessel dilation, muscle contraction and sexual function.
Histamine is produced primarily by specialised immune cells called mast cells, which release it when your body detects an injury, infection or allergen. Histamine is also found in many foods, particularly those that are aged, fermented, cured or processed.
Normally, your body keeps histamine in balance by breaking down any excess. Two enzymes do most of this work. Diamine oxidase (DAO) breaks down histamine from food in your gut. Histamine-N-methyltransferase (HNMT) metabolises histamine made inside your body's tissues. When these enzymes work efficiently, histamine levels stay within a healthy range.
What is histamine intolerance?
Histamine intolerance (HIT) happens when more histamine builds up in your body than it can break down. It is not the same as an allergy. Instead, it is an imbalance between how much histamine enters or is released in your body and how well your body can clear it.
Unlike a food allergy, where symptoms usually happen quickly after exposure to one specific trigger, histamine intolerance can build up gradually. Imagine a sink with the tap running. Histamine is the water flowing into the sink, and the drain is your body's ability to remove histamine. If more water enters than can drain away, the sink eventually overflows. Similarly, when histamine adds up from food, stress, illness or other triggers, symptoms may only appear once your body’s “histamine bucket” is full. This explains why someone may tolerate a food one day but react to the same food on another day when their histamine load is already high.
Because histamine receptors are found throughout your body, symptoms can affect many different areas. Common symptoms include skin symptoms such as flushing, itching, hives or eczema; nose and breathing symptoms such as congestion or wheezing; digestive symptoms such as reflux, bloating, diarrhoea or constipation; urinary symptoms; or symptoms such as headaches, migraines, dizziness, brain fog, fatigue, anxiety, palpitations or sleep disturbance. Some people also notice sensitivity to medicines, strong smells and temperature changes. Most people experience only some of these symptoms, not all of them.
Symptoms often fluctuate from day to day depending on diet, stress levels, hormonal changes, medications and overall health, making histamine intolerance difficult to recognise. Many of its symptoms also overlap with conditions such as allergies, irritable bowel syndrome, anxiety disorders and perimenopause and menopause, which can delay diagnosis.
Why does histamine intolerance happen?
Histamine intolerance can happen for several reasons. Too much histamine may be entering or being released in your body, your body may not be breaking it down well enough, or both these processes may be happening at the same time.
One of the most common contributors is diet. Foods that are aged, fermented, cured, smoked or processed naturally contain higher levels of histamine. Other foods, known as histamine liberators, stimulate mast cells to release more histamine even though the foods themselves may not contain large amounts of histamine. Regular consumption of these foods can overwhelm your body's ability to eliminate histamine efficiently.
Reduced activity of the DAO enzyme is another major factor. Some people inherit genetic variations that result in lower DAO or HNMT enzyme activity, making them naturally less efficient at clearing histamine.
Several commonly prescribed medications – including non-steroidal anti-inflammatory drugs (NSAIDs), certain antidepressants and some painkillers – can reduce DAO activity and contribute to histamine accumulation.
Gut health also plays an important role. DAO is mainly made in the lining of your small intestine, so conditions that affect your gut, such as coeliac disease, inflammatory bowel disease or bacterial overgrowth, can reduce DAO production. Poor gut health and changes in the gut microbiome may therefore make some people more likely to develop histamine intolerance.
Stress is another important contributor. During periods of chronic stress, cortisol and other stress hormones stimulate mast cells to release more histamine, increasing the overall histamine load. Similarly, infections and chronic inflammatory conditions, including Long COVID, have been associated with increased mast cell activation and excessive histamine release.
For many people, histamine intolerance develops because several of these factors occur simultaneously. For example, someone with mild genetic susceptibility may only develop symptoms during a particularly stressful period, after repeated antibiotic use affecting gut health, or during hormonal changes such as perimenopause or menopause.
Histamine intolerance and hormonal changes
Histamine intolerance is particularly relevant during perimenopause and menopause because of the close relationship between histamine and estrogen.
Estrogen can encourage mast cells to release histamine. Histamine can then encourage your ovaries to produce more estrogen. Higher estrogen levels can also reduce DAO activity, making it harder for your body to break down histamine. Together, these effects can create a cycle in which histamine levels rise.
During perimenopause, hormone levels fluctuate considerably. These unpredictable surges in estrogen can cause corresponding increases in histamine levels, which is why many women first notice symptoms during their 40s. They may suddenly develop reactions to foods they previously tolerated, notice worsening hay fever or eczema, experience migraines, flushing, palpitations or increased sensitivity to alcohol.
Women who are still menstruating may also notice that symptoms worsen around ovulation or in the days before their period, when estrogen levels naturally peak.
The hormones progesterone and testosterone are really important for your inflammatory cells to function properly, and low levels of these hormones can increase allergies in the body. Levels of progesterone and testosterone often reduce in women in their 20s, 30s, and 40s and levels of progesterone often fluctuate and change throughout the menstrual cycle.
Hormone treatments (hormone replacement therapy or HRT) add another layer of complexity. For most women, hormone treatments significantly improve perimenopausal and menopausal symptoms and provide important long-term health benefits. However, in women with underlying histamine intolerance, introducing estrogen may temporarily increase histamine production or reduce its breakdown, leading to worsening of histamine-related symptoms.
This does not necessarily mean hormone treatments should be stopped. Instead, it highlights the importance of taking a holistic approach. Symptoms should be assessed carefully and optimising gut health, reducing dietary histamine and reducing other triggers may allow women to continue benefiting from hormone treatment while reducing histamine-related symptoms.
Many women with histamine intolerance find that being prescribed testosterone (if their level is low) and progesterone very beneficial. Often these hormones are prescribed without estradiol and then if needed, estradiol is prescribed at a later time.
How is histamine intolerance diagnosed?
There is no specific test for histamine intolerance. DAO levels can be measured in the blood, but this does not always reflect how well DAO is working in your gut, so it is not an accurate way to make a diagnosis.
Diagnosis is usually based on symptoms, medical history and a trial of reducing high-histamine foods for 2-4 weeks, followed by gradual reintroduction to identify individual tolerance. This approach is generally considered when someone has more than two symptoms that could fit with histamine intolerance.
How to manage histamine intolerance
There is currently no single treatment that cures histamine intolerance. Instead, management focuses on reducing the overall histamine load, improving your body's ability to break down histamine and addressing any underlying factors that may be contributing to symptoms. As histamine intolerance varies greatly between individuals, treatment should be personalised and reviewed regularly with an appropriately qualified healthcare professional.
Diet and optimising gut health
Changing your diet is the first important step to managing histamine intolerance. The aim is not to eliminate histamine-containing foods permanently, but to temporarily reduce the overall histamine burden so that symptoms can improve while individual triggers are identified.
A low-histamine diet is usually followed for approximately 2-4 weeks under the guidance of a dietitian or nutritionist with experience in histamine intolerance. During this time, high-histamine foods or those that stimulate histamine release are reduced or avoided. A food and symptom diary can identify patterns and help recognise personal triggers. Alcohol is usually high in histamine and slows histamine breakdown – those with HIT are often sensitive to alcohol-containing food and drinks and will need to eliminate these too.
Foods to avoid
The British Dietetic Association (BDA) advises that these foods are high in histamine or other vasoactive amines. Remember, levels will vary depending on the age of the food and processing – this is only a guide.
High in histamine and may also contain other vasoactive amines
Meat and poultry: Pork (including ham, bacon, etc), aged and cured meats, game, aged beef
Seafood: Oily fish (tuna, sardine, etc), processed fish products (eg, pate, smoked or dried fish), white fish that’s not freshly caught, shellfish
Milk and eggs: Matured cheeses (eg, Brie, Cheddar), sheep’s and goat’s cheese, fermented dairy (eg, sour cream, yoghurt)
Condiments and misc: Hoisin, soy, tamarind, Worcestershire sauces, tomato ketchup, Marmite/yeast extract
Drinks: Red and white wine, Champagne, beer, cider
Foods that are only high in other vasoactive amines and not histamine
Condiments and misc: Chocolate
Drinks: Rose wine, fruit juices, coffee (coffee pods are lowest), black and green tea
Foods containing histamine and also contain other vasoactive amines - lower amounts than above, they may not need to be excluded
Vegetables: Aubergine, fermented veg, spinach, tomato (concentrated forms such as puree, canned are higher than fresh)
Fruits: Grapes (unclear regarding raisins and sultanas so monitor and adjust as needed)
Legumes: Fermented soya (including black bean paste, miso, tempeh)
Foods containing vasoactive amines (not histamine) - lower amounts than above, they may not need to be excluded
Vegetables: Asparagus, avocado, green beans, broccoli, celeriac, chard, courgette, cucumber, green pepper, peas, pumpkin, sweetcorn
Fruits: Bananas, grapefruit, kiwi, tangerines, oranges, limes, lemons, papaya, pear, pineapple, strawberries
Legumes: Soya beans, lentils
Nuts: Pistachios
After the initial elimination phase, foods are gradually reintroduced one at a time to identify individual tolerance levels. This helps create a personalised, sustainable eating plan rather than a long-term restrictive diet.
Tolerance varies considerably between individuals, and many people can eventually reintroduce a wide variety of foods once their overall histamine load has reduced. Support from a dietitian can be valuable because a low-histamine diet can be socially and nutritionally restrictive.
Food freshness is also important. Histamine levels naturally rise as foods age, even when they are kept in the fridge. Freshly prepared meals are usually better tolerated than leftovers. If you do have leftovers, cool them quickly and freeze them rather than keeping them in the fridge for several days. Storage and manufacturing processes can also affect the histamine content of food.
Because healthy gut function plays a central role in histamine metabolism, supporting gut health through a balanced diet, identifying and treating underlying gastrointestinal conditions where appropriate, and maintaining adequate fibre intake may improve histamine tolerance over time. Some probiotics may be beneficial, although certain bacterial strains can produce histamine and may worsen symptoms in susceptible individuals. Probiotic selection should be individualised and ideally guided by a healthcare professional.
Medications and supplements
Medications and supplements can help reduce symptoms but are generally considered supportive treatments rather than a replacement for dietary and lifestyle measures.
Antihistamines work by blocking histamine receptors, reducing the effects of excess histamine rather than lowering histamine levels themselves. H1 antihistamines, such as cetirizine, loratadine or fexofenadine, are commonly available over the counter and may help relieve symptoms including itching, flushing, hives and nasal congestion. In some individuals, prescription H2 blockers may also be used, particularly where excess stomach acid or reflux is a prominent feature.
DAO supplements are available without prescription and may be taken before meals that are expected to contain higher amounts of histamine. They may be particularly useful for occasional social occasions or dining out, although they can be expensive and are not generally recommended as a substitute for dietary management.
Several nutrients have also been investigated for their possible role in histamine metabolism. Vitamin C may help reduce circulating histamine levels, while vitamin B6 and magnesium are involved in normal enzyme function. Quercetin and luteolin are plant compounds that may help stabilise mast cells and reduce histamine release, although the evidence remains limited. Supplements should be chosen according to individual need and discussed with a healthcare professional rather than taken routinely.
Stress management
Psychological stress is a recognised trigger for mast cell activation and histamine release. Chronic stress may therefore increase the overall histamine load and contribute to symptom flares.
Incorporating stress-management techniques into daily life may help reduce symptom frequency and improve overall wellbeing. Practices such as mindfulness, meditation, yoga, breathing exercises and spending time in enjoyable activities have all been shown to support stress reduction. Regular physical activity also offers benefits, although some individuals find that high-intensity exercise temporarily worsens symptoms. Finding an exercise routine that is well tolerated is therefore important.
Hormone treatments
Hormone treatments (HRT) remain the most effective treatment for perimenopausal and menopausal symptoms and provides significant long-term health benefits, including reducing the risk of osteoporosis and improving cardiovascular health when appropriately prescribed.
Some women with underlying histamine intolerance may notice that histamine-related symptoms temporarily worsen after starting estrogen therapy because estrogen can stimulate histamine release and reduce DAO activity. However, this does not necessarily mean that hormone treatments should be avoided. Progesterone and testosterone can stabilise mast cells, while improvements in sleep, stress, gut health and overall wellbeing associated with effective perimenopause and menopause management can also improve histamine tolerance.
For women with suspected histamine intolerance, hormone treatments should be individualised, with careful monitoring of symptoms and adjustment of treatment where necessary. Managing histamine intolerance alongside perimenopause and menopause often allows women to continue benefiting from hormone treatments while minimising histamine-related symptoms.
Key takeaways
Histamine intolerance is best understood as a load-and-tolerance issue rather than a single-food problem. The aim is to reduce avoidable triggers, support your body’s ability to break histamine down and avoid unnecessary long-term restriction.
Histamine intolerance is a potential contributor to symptoms experienced during perimenopause and menopause. Looking at both hormonal health and histamine balance may help improve symptom control and quality of life.
Resources
BDA. (2023), 'Histamine intolerance and the low histamine diet'
Swiss Interest Group Histamin Intolerance (SIGHI)
