Histamine has other roles too, like helping with digestion, wound healing, and nerve signaling in the brain1. Because of this, it’s important to have some, but problems arise when you’re exposed to too much or develop a reaction to normal amounts. A histamine intolerance develops when the amount of histamine that accumulates in your body is greater than the amount of histamine your body can eliminate. Having a histamine intolerance doesn’t mean that you’re allergic or sensitive to histamine; it simply means that there’s too much in your body. Some things that can cause a histamine intolerance are: Normally, histamine travels to the gut, where DAO breaks it down and prevents it from entering the bloodstream. However, if you don’t have adequate levels of DAO, histamine passes through the small intestine, where it gets into your blood. Over time, this can lead to high levels of histamine that cause the uncomfortable symptoms associated with histamine intolerance. So, what causes low DAO? In some cases, your genes may play a role, but things like excessive alcohol consumption, overuse of NSAIDs, leaky gut, and small intestinal bacterial overgrowth (or SIBO) can also reduce your levels. Some of the most common complaints are: There’s no direct testing for histamine intolerance, but your doctor can use a combination of tests to determine the likelihood that you have it. Some of the most useful options are: Your body naturally produces histamine, but the chemical compound also comes from the food you eat. The goal of a low-histamine diet is to drop your body’s histamine levels. This is done through a combination of avoiding foods that are high in histamine (and foods that trigger your body to release histamine) and using proper food preparation and storage techniques. Although a low-histamine diet can feel overwhelming at first, it’s highly effective and worth the effort if you have histamine intolerance. In one study, participants with chronic hives were put on a low-histamine diet. After four weeks, all participants saw significant reductions in blood histamine levels3 and body distribution of hives. In addition to directly lowering the amount of histamine in your body, other research shows that a low-histamine diet can also increase the amount of DAO4 that the body makes, helping to boost its ability to break down excess histamine. For example, functional medicine doctor Frank Lipman, M.D., explains that raw meats, poultry, and fish have a high bacterial count, and as the bacteria ferment the food, they create histamine as a byproduct. Zibdeh echoes this, saying that a good way to combat the natural histamine increase in high-protein foods is to, “Buy them fresh and cook or freeze them the same day, as freezing stops histamine buildup. Don’t leave them in your fridge for a few days, and definitely not on your counter or in your car. Alternatively, buy frozen products like individually wrapped salmon or cod fillets. To thaw, place them in a sealed bag and submerge in cool water for 15 to 30 minutes instead of leaving them in the fridge overnight.” Zibdeh recommends freezing any meals that you cook in batches or during meal prep right away. She also advises transferring the leftovers to glass containers in individual meal sizes (or enough to feed your whole family for one night) right after the food cools off and investing in glass containers instead of reheating in plastic. When you do reheat the meal, do it quickly in the oven or the microwave as opposed to letting it thaw in the fridge overnight. While you may start to see results within one week of following the diet, Zibdeh says that the goal is to stay on it for about a month to reap the full benefits. Once the root cause is addressed and fixed, you should be able to tolerate histamine-containing and histamine-triggering foods better. Supplemental DAO is also available in capsule form. You can take DAO when you eat histamine-containing foods to help break them down so your body can handle them better. However, DAO supplements only work in your gut, so they can’t help with the histamine that your body naturally produces, according to Zibdeh. Another downside is that DAO supplements only work while you take them. Researchers from one study5 instructed 28 participants with histamine intolerance to take DAO capsules for four weeks and then report the severity of their symptoms. All of the participants had improvements in their symptoms, but as soon as they stopped taking the supplements, the symptoms came back. While supportive nutrients and supplements can help make you more comfortable, it’s vital that you work toward figuring out the root cause of your histamine intolerance. Finding the underlying cause—and working to correct it—is the only long-term, permanent solution to getting rid of histamine intolerance for good. If you suspect you have a histamine intolerance, a low-histamine diet can help confirm (or rule out) your suspicions. Although a low-histamine diet can help alleviate symptoms within a week, it’s only a short-term solution. Identifying—and correcting—the underlying problem is vital to getting rid of a histamine intolerance for good. She has written twelve books and has had more than 2,000 articles published across various websites. Lindsay currently works full time as a freelance health writer. She truly believes that you can transform your life through food, proper mindset and shared experiences. That’s why it’s her goal to educate others, while also being open and vulnerable to create real connections with her clients and readers.
