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Histamine Intolerance: When Allergies Get Out of Hand

In this day and age, the food we eat and the lifestyles we lead don’t always leave us feeling so great. Headaches, constipation, lethargy, gas, bloating, etc. are things we’ve all experienced at some point. But nailing down the exact cause of our symptoms can be a real challenge—oftentimes they can signify anything from daily wear and tear to a more serious medical issue. So how do you know which one it is?


The first step towards finding the answer is usually to start the Paleo diet, which keeps from us eating the foods that tend to lead to the annoying symptoms listed above. Many people will find their quality of life transformed after being on the Paleo diet for an appropriate length of time. But if you’ve given the Paleo diet a try and your symptoms remain, it might be time to look at some other explanations for that persistent feeling of illness. One of those explanations is histamine intolerance.

Before I talk about histamine intolerance, I want to say a bit about what histamines are and the purpose they serve. Histamines are chemicals that we come into contact with in a few different ways. The first and most common way is when the body itself releases histamines. This happens any time an allergen triggers the immune system. Once released, the histamines leave us with runny noses, rashes, itchy throats, and the other typical allergy symptoms most of us know all too well. We also come into contact with histamines when 1) we eat foods containing them and 2) certain bacteria in our guts produce them. 

To keep histamine production under control, our bodies produce an enzyme called diamine oxidase (DAO). DAO breaks down these histamines, subduing the allergic reaction. But some people have a deficiency of DAO, which means histamines are allowed to build up inside the body over time. Histamine buildup can lead to a variety of symptoms including migraines, digestive upset (constipation/diarrhea), nausea, and low blood pressure, in addition to all the other allergy symptoms listed above. In other words, you may have what feels like an allergic reaction but in the absence of any allergen at all. We call this histamine intolerance. 


Histamine intolerance, unfortunately, is often hard to diagnose because most of these symptoms (runny nose, headache, constipation, etc.) are nothing out of the ordinary. However there is at least one give-away to the histamine intolerant—they always respond poorly to foods that contain high levels of histamines. Although your body produces them as well, our biggest histamine source tends to be the food we eat. In reality, its not the food that contains the histamines—it’s the bacteria living on the food. Anything aged or fermented will contain a lot of these histamine-producing bacteria—think yogurt, aged cheese, cured meat, alcohol, vinegar, fish and seafood, mushrooms, dried fruit, and more. Sometimes even leftovers contain enough bacteria to cause problems. 

However, a person’s reaction to specific foods can very widely. For example, someone might be able to eat fish from one store without a problem, but suffer terribly after eating fish from another grocery store or restaurant.  There are also foods that don’t actually contain histamines themselves, but rather cause our bodies to produce more histamines, like spinach, citrus fruit, pineapple, pork, shellfish, chocolate, and nuts. Individual sensitivities to these foods often vary greatly, but most of the time people are primarily affected by only the very high-histamine foods, which like I said, includes anything aged or fermented.

The best way to diagnose histamine intolerance is to follow a customized histamine-elimination diet for four weeks. After that time, the patient should reintroduce the eliminated foods to see if there is any noticeable difference in well-being. A food journal and the guidance of a medical practitioner can be valuable tools in diagnosing histamine intolerance. If you want to know more about what foods should be avoided in a histamine-elimination diet, please see the following link: http://ajcn.nutrition.org/content/85/5/1185/T3.expansion.html

If you believe high-histamine foods might be behind your symptoms, there are a couple things you can do to feel healthy again. In addition to avoiding the foods containing the most histamine, you’ll want to make sure your meat is as fresh as possible or frozen as soon as possible after slaughter. It’s also important to pay attention to your gut health. Like I said earlier, some of the bacteria in our guts produce histamines. If the bacteria population in our guts becomes imbalanced (due to taking antibiotics, eating the wrong foods, etc.), then histamine buildup can become a problem. Taking particular probiotics, like Lactobacillus and Bifidobacterium, can help suppress this histamine release. Other helpful supplements are Vitamin B6, copper, and Vitamin C. These nutrients encourage a healthy population of DOA, which again, eliminates histamines. 

At this point in time, scientists are unsure just how much of the population is histamine intolerant. If you’re having allergy symptoms accompanied by digestive upset, headaches, low blood pressure, etc. for no apparent reason, you might be one of those affected. Luckily, simply giving your diet a little more attention can often alleviate the symptoms of histamine intolerance. The best way to find out more is to contact your healthcare practitioner about crafting a histamine-elimination diet and reintroduction to see the difference for yourself.