What to do when histamine symptoms are taking over Is your histamine reaction sometimes too much to handle?Do some meals leave you with a stuffy nose, irritated, watery eyes, or difficulty breathing? Perhaps unexplained headaches, anxiety or your heart racing?Have you broken out in hives, after eating certain meals, or been left with unbearable digestive symptoms? If some of these symptoms sound familiar, you may be experiencing a histamine reaction. The good news is, there are a number of things you can do to prevent histamine reactions, and to treat them when they happen.Histamine without IntoleranceThe reason it can be so difficult to distinguish allergy from histamine intolerance is that the symptoms can be so similar.Histamine is a key mediator in an allergic response, so it is no wonder allergies and histamine reactions can be mistaken for one-another.Most histamine in the body is produced and stored in small granules within mast cells and, is released in response to an allergen or other inflammatory trigger. Histamine containing mast cells are an important part of our immune system, protecting us from invading pathogens and helping to elicit wound healing.Mast cells are found all over the body, and are particularly abundant at sites of potential injury, such as the nose, mouth, feet, blood vessels, intestines and lungs (1). For this reason, histamine reactions tend to affect these tissues. Histamine is also found in the brain where it functions as a neurotransmitter and, in the stomach where it orchestrates the release of gastric acid to digest our food (1).In addition to being a natural part of our biology, histamine is present in many of the foods we eat and components in the environment. If you have ever brushed against stinging nettles you will have experienced a direct response to the histamine in the plant (2). Histamine is even present in the venom of insects such as bees and wasps, resulting in the swelling and stinging of the bite that you experience (2).Eliminating incoming histamine is the reason why histamine intolerant individuals experience fewer histamine reactions when eating a low histamine diet. What is a histamine reaction? When you experience a histamine reaction, it is the response of your body to excess histamine in your blood or tissues.Histamine exerts its intended effects on various tissues of the body via histamine receptors, which are something like a dock for histamine. When histamine binds a receptor, this signals a particular response, such as gastric acid release, dilation of blood vessels, inflammation, immune attack of invading pathogen or neuronal signaling, all aiming to protect us or carry out helpful bodily functions.However, when our histamine levels are too high, this signaling can go haywire, resulting in a histamine reaction. Symptoms of a histamine reactionHistamine reactions can emerge in many forms. I've summarized some common symptoms by body system below - but, you can also check out my more comprehensive list of histamine intolerance symptoms. Effects of excess histamine on the central nervous system can include nausea, headache, vertigo or sleep disturbances (3).Effects on the cardiovascular system are mainly due to dilation of the blood vessels which may cause a drop in blood pressure, flushing of the cheeks, and dizziness.Effects on the skin can include rash, hives, flush and itchiness.Effects on the airways include nasal congestion, runny nose, sneezing, and constricted or wheezy breathing (like asthma).Effects on the digestive system include acid secretion, diarrhea, stomach aches and cramps, bloating and flatulence.Effects on the hormonal system include menstrual cycle disturbance, headache associated with the menstrual cycle (3) and low mood.Histamine is produced by our bodies, by the bacteria in our gut, and is in many of the foods we eat. It doesn’t normally cause us any problems when the levels are low. The problem is when our bodies are unable to get rid of it as rapidly as it is produced or taken in through the diet.It's something like a bucket of water that will overflow once its capacity has been exceeded - essentially, you won't notice the consequence that is a histamine reaction until its levels rise above the threshold, and the bucket overflows.But, the good news is that if you experience histamine reactions, there are probably a number of changes you can make to lower your levels of histamine so that your bucket is only half full.Once you have managed to reduce your histamine levels, you may even be able consume small amounts of the foods that used to cause you itchy eyes, runny nose, headaches without experiencing any symptoms.Root Causes of Histamine Reactions Increased production or decreased degradation of histamineSome of us are particularly susceptible to histamine reactions because we are unable to break down histamine as effectively as most, and there can be multiple reasons for this(4). For example, if you are not producing enough of the histamine-degrading enzyme Diamine oxidase (DAO) due to impaired gut health, genetic issues or lack of cofactors (3,5), you may not be able to break down or inactivate histamine effectively. For example, damage to the cells that produce DAO in the intestines is just one of the reasons why gastrointestinal disease is commonly linked with histamine intolerance(4). Additionally, during pregnancy, DAO is produced at high concentrations by the placenta (6), which may explain why food intolerances commonly subside during pregnancy (7). If you suspect a DAO deficiency is your issue, you can try these natural ways to increase DAO enzymes. Increased conversion from histidine to histamineAnother cause of elevated histamine can be high levels of the enzyme that produces histamine from the amino acid histidine (histidine decarboxylase). Methylation deficiencyMethylation is a buzz word you hear a lot in nutrition circles, as it is so fundamental to many processes in the body. And, it's not uncommon to have deficient methylation for one reason or other (genetic, nutritional, etc.). HNMT is an enzyme that inactivates histamine via a methylation reaction. So, if you have insufficient methylation capacity (eg. due to B12 deficiency, folate deficiency or MTHFR polymorphisms) this may reduce histamine inactivation inside cells by HNMT. Allergy and inflammationSince histamine is released as part of the allergic and inflammatory responses, the presence of allergy or chronic inflammation will increase your basal histamine levels. This is why individuals with a seasonal allergy to pollen, for example, may experience a histamine reaction to tomatoes, citrus or spinach only during pollen season. Dietary sources of histamineMany foods contain histamine, while others contain histamine releasing substances. The classic culprits for causing histamine reactions are aged and fermented foods. However, histamine is surprisingly high in a number of fresh, healthy and all-natural foods such as spinach and tomatoes. For this reason, I've created a free and comprehensive low histamine diet that you can download. MedicationsCertain medications can also cause histamine release. So, if you are on any medications and think you suffer histamine sensitivity it could be worth discussing this with your doctor. Gut flora imbalanceThe composition of your gut flora is important in determining the levels of histamine you are exposed to. If you have an overgrowth of histamine-producing bacteria, more histamine will be produced during the breakdown of dietary protein. This also means that a high protein diet (especially animal protein such as fish, meat, dairy and eggs), may result in further elevations in histamine production than a lower protein diet. On the other hand, we also have strains of bacteria that degrade histamine, so for the sake of reducing histamine load, its beneficial for our gut to be colonized by more of these varieties. In this case, I recommend trying out a low histamine probiotic.Top 5 tips to stop histamine reactionsNow that you know what causes may be underlying your histamine reaction, it's time to learn how to prevent, control or stop a histamine reaction. The goal is to keep your bucket half empty so that there is room for the unavoidable histamine that is part of life.Here are my top tips for dealing with a histamine reaction. 1) Ginger - Although sticking to a low histamine diet can help to prevent histamine reactions in the first place (8,9), consuming antihistamine foods can actually help to calm a histamine reaction while it's happening. One of the strongest known antihistamine foods is ginger. If you're experiencing a histamine reaction, try chewing on fresh ginger or pouring boiling hot water over sliced ginger to make fresh ginger tea. In general, you can also drink ginger tea before bed to act as a natural antihistamine and prevent histamine reactions.2) Mast cell stabilizers - One way to calm you histamine reaction is to stabilize mast cells in order to slow the natural release of histamine in response to your sensitivity. This method can not only calm your reaction but, can also boost your body's natural histamine tolerance so that you can consume more foods with fewer symptoms. It's important to choose a supplement specially formulated to address histamine intolerance via multiple routes such as D-Hist which contains a selection of natural ingredients that work together to help stop histamine release and regain tolerance.3) Keep a food diary. By paying attention to the foods you react to, you will be able to build up a list of foods to avoid that is relevant to you. Make sure you are including all of the relevant information rather than just foods. I've put together an example food diary you can print out and use.4) Diamine oxidase - It's possible to take DAO in supplement form to increase the breakdown of histamine within the body and assist with a histamine reaction. However, the majority of DAO supplements are derived from pigs and are unsuitable for vegans. Trying natural methods to increase DAO enzymes may be a better route for controlling your histamine reactions before and during their occurrence.5) Pea sprouts - An alternative to taking DAO supplements is to consume pea sprouts. When seeds sprout, they produce DAO, and pea sprouts have even been found to have the highest DAO levels (10). You can sprout peas in water, preferably in the dark for 10-12 days, then blend in a smoothie (roots and all) and consume fresh.6) Avoid histamine releasing triggers and allergens - Any allergies you have will trigger histamine release, so learning what these are and avoiding them is key to keeping histamine reactions to a minimal. Remember, it's not all about food. Histamine release can be triggered by medications, skin creams, sunscreen, face wipes, airborne irritants and household products.7) Histamine-friendly probiotics: If gut flora imbalance is contributing to your histamine overload, a probiotic may help re-establish balance. But, be sure to choose a probiotic formulated to promote histamine degradation - otherwise, regular probiotics can often make symptoms worse as the bacteria will naturally produce histamine. I recommend trying out this hypoallergenic, low histamine probiotic, which is one of the few histamine-safe probiotics on the market.8) Focus on gut health. A leaky gut, IBS or other bowel trouble increases the level of inflammation both in the gut and the rest of the body. You want to keep inflammation levels down, as inflammation means histamine release. Focusing on gut health is a method to not only prevent histamine reactions before they happen but, begin improving and healing your intolerance, and making histamine reactions less frequent in the first place. Eating a healthy, low histamine diet that contains all of your essential nutrients while also focussing on your gut bacteria is a great start to this.9) Make sure you're on the right diet - Remember, it's not just high histamine foods that can trigger a histamine reaction. Histamine releasing foods or foods which are high in precursors for histamine can also cause symptoms, even if the food isn't high in histamine itself. These food can be hard to identify, which is why I've created a low histamine food list that includes all histamine symptom triggers and identifies more food culprits than your typical low histamine diet. Click the button below to get your free copy: Get the Diet Your Next Histamine ReactionNow that you have tools to help you to both deal with and prevent having histamine reactions in the first place, try them out next time you expect to be eating questionable foods, feel a histamine reaction starting to bubble up or, simply incorporate these into your daily routine in order to minimize the chance and severity of potential reactions.Do you have a method of dealing with histamine reactions at home? Share what's worked for you in the comments below! References:1. Benly P. Role of Histamine in Acute Inflammation. 2015;7(6):373–6.2. Abbas Abul K., Lichtman; AH, Pillai S. Cellular and Molecular Immunology. Vol. 8a ed., Elsevier. 2014. 544 p.3. Maintz L, Novak N. Histamine and histamine intolerance. Am J Clin Nutr. 2007;85(5):1185–96.4. Maintz L, Bieber T, Novak N. Histamine Intolerance in Clinical Practice. Dtsch Arztebl. 2006;103:3477–83.5. Johnston CS. The antihistamine action of ascorbic acid. Subcell Biochem. 1996;25:189–213.6. Morel F, Surla A, Vignais P V. Purification of human placenta diamine oxidase. Biochem Biophys Res Commun. 1992;187(1):178–86.7. Reinhart J, Felix W. Wine and Headache. Int Arch Allergy Immunol. 1996;110(1):7–12.8. Schwelberger HG. Histamine intolerance: A metabolic disease? Inflamm Res. 2010;59(SUPPL. 2).9. Vickerstaff Joneja JM, Carmona-Silva C. Outcome of a Histamine-restricted Diet Based on Chart Audit. J Nutr Environ Med. 2001;11(11):249–62.10. Masini E, Bani D, Marzocca C, Mateescu MA, Mannaioni PF, Federico R, et al. Pea seedling histaminase as a novel therapeutic approach to anaphylactic and inflammatory disorders. A plant histaminase in allergic asthma and ischemic shock. 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