It’s springtime, which means flowers and sunshine and new life and…allergies! As the world comes out of hibernation, many conversations are turning to the topic of allergies and the histamines that cause them. But what most people don’t know is that histamines are responsible for much more than just the sneezing fit you get when the oaks come into bloom. In fact, as Dr. Brooke Kalanick, a naturopathic physician, women’s hormone expert, and author of the book Hangry (who goes by the moniker “Dr. Brooke”) explained, histamines are involved in multiple different organ systems and can have wide-ranging effects on your health. Read on to learn what high histamine levels mean, the most common high histamine symptoms, the upsides and downsides of a histamine intolerance diet, and much more.
How Dr. Brooke Went from Pharmacy Student to Naturopath
When Dr. Brooke graduated from college as a pre-med student, she wasn’t sure exactly what medical track she wanted to take. She was somewhat interested in pharmacy school and, on the advice of those around her, applied. When she got in, she wasn’t sold on that particular career path but wasn’t sure what else she wanted to do more, so she began working toward a Doctor of Pharmacy degree. But then, as is the case with so many people who go on to become integrative doctors, her own health started suffering.
She’s been diagnosed with PCOS at age 16, and had been dealing with the attendant symptoms since then. Upon giving her the diagnosis, her doctors had simply prescribed her the birth control pill and told her to come back and see them when she wanted a baby. “So I was given the pill, and I never did well on it,” Dr. Brooke says. “I would always take myself off because I didn’t feel right on it.“ But when she stopped taking the pill, her PCOS symptoms would come roaring back, with her skin breaking out and her menstrual cycle disappearing.
By the time she was in pharmacy school, she’d reached the end of her rope with this pattern. Her health was suffering, and nothing she’d learned or was learning gave her any indication of how to fix it. “I didn’t know what to do, and my conventional answers just weren’t really working for me,” she says.
So she looked outside of the conventional medicine realm, finding her way to a naturopathic doctor. The ND gave her some simple, lifestyle-based advice, things like cutting down on excessive exercise, focusing on her sleep, taking B vitamins, and keeping her blood sugar balanced. With these small changes, Dr. Brooke says, “my life was transformed.”
Having seen what a naturopathic approach could do that pharmaceuticals couldn’t, Dr. Brooke decided to jump ship before completing pharmacy school. She pulled out of the program at Washington State University and headed to Bastyr University, a naturopathic medicine school outside of Seattle, where she earned a Doctorate in Naturopathic Medicine and a Masters in Acupuncture and Chinese Herbal Medicine.
After completing her training, Dr. Brooke moved to New York City, and her journey has evolved from there. Spurred by her own hormonal issues, she continues to focus on women’s health, and has come to incorporate strength training and fitness in her practice because, as she says, “doctors are always telling their patients to exercise, but they aren’t giving them any advice on how to do that.” Today, she describes her practice as “very holistic,” incorporating stress management, exercise, nutrition, and sleep, as well as her naturopathic and Chinese Medicine training. “It’s been great to have solved some of my own problems and ended up with a clear path of where I was going to go,” she says.
So, What Are Histamines?
Before we get into the specifics of high histamine levels, histamine intolerance, and high histamine symptoms, it’s important to back up and get clear on what, exactly, histamines are. Histamines are sometimes described as a hormone, sometimes as a neurotransmitter, and both of these definitions make sense because of the variety of different ways they act. On the most scientific level, a histamine is an organic, nitrogen-based compound that is involved in local immune responses, regulating gut function, and acting as a neurotransmitter that delivers messages to the brain, spinal cord, and uterus.
As Dr. Brooke explains, histamines are very important compounds that can act as neurotransmitters in some cases and immune mediators in others. They’re stored in cells known as mast cells, which are a type of white blood cell. Mast cells — and thus histamines — are located in various different tissues around your body, but tend to be found in places where your internal organs meet the outside world: your gut lining, your respiratory lining, your skin, etc.
When most people think of histamines, they’re usually thinking of their role in immune function. When you get injured or come in contact with an allergen or irritant, histamines in the area will trigger an inflammatory response, recruiting white blood cells to handle the issue. As with any acute inflammation, there’s often heat and swelling, but histamine reactions can also cause symptoms that we most commonly associate with allergies, like itching, redness, or rashes.
While lesser known, histamine’s role as a neurotransmitter is equally important. Histamines are part of your sleep-wake cycle, which explains why certain antihistamines, which block histamine receptors in the brain, make you sleepy. They’re also important in digestive processes like stomach acid secretion and gastric motility, and their relationship with female hormones mean that they play an important role in uterine contraction and can even impact sexual arousal. Who knew?!
High Histamine Levels and Histamine Intolerance
As often happens in the wellness world, a certain term or diagnosis bubbles to the top of the conversation and people begin attaching to it. The idea of “histamine intolerance” is one of the more recent bubbles. Dr. Brooke says that she frequently sees patients who believe they may have histamine intolerance, and her job is to discern if this is the case, or if (more likely) they’re simply dealing with high histamine levels.
To explain the difference between the two, Dr. Brooke offers the analogy of a bucket: our bodies are the bucket, and there’s a flow of histamines coming in and a drain of histamines going out. The flow coming in could be any number of things, from environmental allergens to food sensitivities to high histamine foods to a chronic condition (more on that below). The drain coming out is mediated by enzymes (most notably diamine oxidase, or DAO), which pass through the liver and then clear the histamine out of your body. “So you might be having a lot of stuff come into your bucket, and then you need to make sure that you can clear it out,” says Dr. Brooke.
With high histamine levels triggered by an allergen, the allergic response is immediate, and your body is eventually able to clear the histamine from your system. A histamine intolerance, on the other hand, occurs when there’s such a buildup of histamine that your body can’t properly break it down. With the drain clogged, your bucket overflows, your high histamine levels continue to get higher, and a cascade of symptoms begin. Unlike an allergy, the symptoms of histamine intolerance are often delayed, since it’s not about one particular trigger but rather a gradual accumulation.
Dr. Brooke explains that this buildup of histamine isn’t a classic allergic reaction, but rather a sign of your body’s inability to properly process histamine. This could be caused by something on either end of the bucket: you might have too much coming in, or there might be something preventing you from properly clearing histamine from your body (or both). The potential root causes of either are varied, and it can take some digging to unearth the source of your high histamine levels.
Some of the most common causes of histamine intolerance include:
- Going on a certain diet that has a lot of high histamine foods
- Chronic inflammation, whether due to a specific condition like Lyme or SIBO or another infection
- An acute infection that triggers histamine resistance
- Exposure to environmental toxins
- Poor gut health (remember, histamines are located in the gut lining)
- Slow liver detoxification
- A genetic predisposition that hinders your body’s ability to produce histamine-clearing enzymes (but remember: genetic predispositions aren’t destiny; your lifestyle choices determine whether these genes get activated)
Dr. Brooke also emphasizes that being histamine intolerant isn’t a permanent diagnosis or chronic condition: it’s something that can be reversed and managed by identifying the cause and treating it accordingly, then being aware of your triggers and managing them to keep high histamine levels at bay in the future.
Understanding High Histamine Symptoms
Even if you don’t get allergies (lucky you!), we’re guessing you’re familiar with allergy symptoms: sneezing, itchy throat, runny nose, rashes, and red, watery eyes. But for those dealing with a histamine intolerance and chronically high histamine levels, the symptoms can be very different from what we think of as an allergic reaction.
Because histamine is involved in so many bodily systems and processes, high histamine levels can trigger a wide variety of symptoms, and which ones a person experiences will depend on the cause of their histamine reaction as well as their unique body. Dr. Brooke laid out some of the most common high histamine symptoms, underscoring that a person experiencing histamine issues might just have one or two of these:
- Acid reflux/GERD
- Loose stools/cramping
- Menstrual cramps/irregular cycle
- Breast tenderness
- Skin rashes or unexplained itching
Figuring out the root cause of a person’s high histamine symptoms can be a frustrating process, says Dr. Brooke. This is because there’s often more than one issue at play, and a person’s histamine intolerance can be linked to or triggered by these other issues, making diagnoses difficult to pin down.
What is clear, she explains, is that gut health is central to your body’s ability to effectively process and clear histamines. This is because DAO, that all-important enzyme we mentioned before, is primarily produced in the lining of the small intestine. So if your gut health is suffering (and especially if you have a condition like SIBO, which specifically affects the small intestine), it will negatively affect your ability to produce this histamine-clearing enzyme.
The histamine-gut connection is also the reason why histamine problems have become increasingly common. “Today, our guts are oftentimes not as healthy as we need them to be because of medications, environmental stress, our food system, our own psycho-emotional stress,” says Dr. Brooke.
She also points out that, because of our increased exposure to environmental toxins, our liver has to work overtime to process and eliminate harmful substances. This could cause it to become overburdened, lessening its ability to process and eliminate histamine and thus contributing to high histamine levels.
Understanding the Histamine Intolerance Diet
Because the gut is so central to your body’s relationship to histamines, it shouldn’t come as a surprise that your diet can impact your histamine response and even be a trigger for histamine intolerance. Yet many people are surprised to learn that certain foods actually contain histamine (we sure were!).
Histamine is a biological molecule made from nitrogen, so it makes sense that it would be present in certain foods, especially fermented foods, since nitrogen is part of the fermentation process. In describing the most histamine-rich foods, Dr. Brooke explains that, “the biggest ones are anything fermented. So all the kombucha, the sauerkraut, the kimchi, all that stuff we’re telling you to eat for your gut — and it is important for your gut! But if you have an underlying histamine intolerance, it might not be the best way for you to get your probiotics.”
She says that besides fermented foods, there are various other foods rich in histamine, including:
- Nuts with a long shelf life
- Aged meats and cheeses. This one is a double whammy: not only do aged meats and cheese contain histamine but, as Dr. Brooke explains, they also monopolize the enzymes needed to break down histamine. This is because as foods age, they develop certain compounds that are broken down by the same enzymes that break down histamines.
She underscores that this list is not comprehensive, nor is there a unanimously accepted histamine intolerance diet. “Start Googling “low histamine diet,” you’ll get a whole variety of different lists,” Dr. Brooke says. “My list that I give out tends to be in the middle. You have to eliminate enough of it to get some relief. If you can get some relief and still keep some of them in, sometimes that’s a little bit better.”
She also emphasizes that the histamine intolerance diet is not the kind of diet a person should stay on for a lifetime. Rather, it’s best used to diagnose a histamine intolerance, or to treat extremely high histamine levels for a short period of time. “It’s a great diagnostic tool,” she says. “If you take all those high histamine foods out and your symptoms go away, then you’re having some sort of histamine intolerance. But you can’t live on that diet forever. It’s incredibly restrictive, and not super healthy.”
For people experiencing high histamine symptoms, she recommends decreasing or eliminating foods rich in histamine for 7 to 14 days, and noticing how you feel. If you feel better, then your symptoms were the result of a histamine intolerance and, as she says, “you’ve dumped your bucket, essentially.” With your bucket empty, your body is once again able to process histamine correctly, and you can return to a more normal diet.
Of course, she explains, knowing that you have a histamine intolerance doesn’t tell you much at all about the root cause of this intolerance. However, it gives you a starting point for investigating the issue and fixing whatever might be contributing to your body’s inability to handle its histamine input.
For people who are naturally predisposed to have histamine issues, they may need to make tweaks to their lifestyle in order to allow them to go off the histamine intolerance diet without experiencing acute flare-ups. If there’s a condition contributing to their intolerance, like SIBO or Lyme, that would mean taking steps to manage that. Others may try taking supplements that support the enzymes you need to clear histamine (generally a mineral, like magnesium or copper, with a B vitamin, like B6 or B12, depending on which enzyme you’re looking to support). They may also need to return to a strict histamine intolerance diet from time to time, just to reset their body and empty their bucket if it gets too full.
The WellBe Takeaway on Histamines and Your Health
Histamines are a complex and important part of your body’s ability to function, and it can be confusing to understand how they impact your health. Here’s what to remember:
- Histamines are organic, nitrogen-based compounds that exist in cells called mast cells throughout our body. Mast cells are mostly found in areas where our body comes in contact with elements from the outside environment (ie, gut lining, respiratory tract, etc.)
- Histamines are part of your body’s immune response, triggering inflammation when there’s an injury or allergen. They also regulate the function of the gut and act as a neurotransmitter, delivering messages to the brain, spinal cord, and uterus.
- Specific enzymes, most notably the enzyme DAO, break down histamine and then clear it from the body through the liver. If a person has too much histamine input, or inadequate enzyme production, they may develop overly high histamine levels that their body cannot clear, which is known as histamine intolerance.
- Symptoms of overly high histamine levels include fatigue, anxiousness, breast tenderness, joint pain, irritability, acid reflux/GERD, and insomnia.
- Histamine intolerance can be caused by a variety of factors, including poor gut health, SIBO, genetic predisposition, chronic inflammation, and acute infection, eating a diet high in histamine-containing foods, environmental toxins, or slow liver detoxification.
- Many foods contain histamine, so those looking to clear histamine from their system should avoid certain foods, including: fermented foods, aged meats and cheese, avocado, spinach, tomatoes, tea, lemons, certain nuts, and shellfish.
- The histamine intolerance diet is extremely restrictive and bad for your gut health, so it should only be used for a short period of time or as a diagnostic tool.
Have you ever experienced histamine intolerance? What do you think the root cause (or causes) are? Let us know in the comments below!
Watch our full interview with Dr. Brooke to learn why and when certain people might need to take mast cell stabilizers (and what Mast Cell Activation Syndrome is), the link between female hormones and histamine response, which supplements are best for reducing high histamine levels, the difference between food allergies and histamine intolerance, the importance of happiness and emotional health in dealing with health issues, the next steps you should take if you think you might be dealing with a histamine intolerance, and much more!
- Krystel-Whittemore, Melissa et al. “Mast Cell: A Multi-Functional Master Cell.” Frontiers in immunology vol. 6 620. 6 Jan. 2016.
- Branco, Anna et al. “Role of Histamine in Modulating the Immune Response and Inflammation.” Hindawi. 27 Aug 2018.
- Barocelli E, Ballabeni V. Histamine in the control of gastric acid secretion: a topic review. Pharmacol Res. 2003 Apr;47(4):299-304.
- Laura Maintz, Natalija Novak, Histamine and histamine intolerance, The American Journal of Clinical Nutrition, Volume 85, Issue 5, May 2007, Pages 1185–1196.
- Bytautiene, E. et al. “Effect of histamine on phasic and tonic contractions of isolated uterine tissue from pregnant women.” GENERAL OBSTETRICS AND GYNECOLOGY OBSTETRICS| VOLUME 188, ISSUE 3, P774-778, MARCH 01, 2003.
The information contained in this article comes from our interview with Dr. Brooke Kalanick, ND, MS, LAc. Her qualifications and training include earning a B.A. in biology from Seattle Pacific University, partially completing a Doctorate of Pharmacy at Washington State University, and earning a Doctorate in Naturopathic Medicine and a Masters in Acupuncture and Chinese Herbal Medicine from Bastyr University. She is a frequent expert and consultant for various outlets, including Fitness Magazine, Oxygen, and Health Magazine, among others. You can learn more about her here.