Here is a guest post from one of our Pharm D Candidate Students from the Class of 2014 – Patricia Waylett
Here is a brief explanation of just that: histamine is a chemical in your body that effects your immune system, proper digestion, and your central nervous system. As a part of your immune system, it sends warnings to your brain to notify your body of any potential attackers, causing an immediate inflammatory response. Histamine opens up your blood vessels and allows your white blood cells (the cells that fight infection) to rapidly find and attack the problem. A histamine buildup is usually unpleasant (to put it lightly), and commonly results in headache, flushing, and that itchy feeling.
All of this is part of the normal immune response to attackers in the body, but it is essential that your body can break down histamine properly when its job is done. Enzymes are needed to break down histamine. Diamine oxidase (DAO) is a main enzyme used in the digestive tract to break down ingested histamine and this is where histamine intolerance comes into play.
If you do not produce enough DAO or have a DAO deficiency, a buildup of histamine will occur and there is a good chance that you will have symptoms of histamine intolerance. There are other ways to have high histamine levels as well, such as allergies, bacterial overgrowth in the gut, leaky gut, gastrointestinal bleeding, and consumption of some foods that are either histamine-rich, release histamine, or foods that block DAO in the body. A list of these foods can be found here: Foods that Promote Excess Histamine in the Body.
Importantly, since histamine travels through your bloodstream and affects many parts of your body such as your gut, lungs, skin, brain, and entire cardiovascular system, histamine intolerance is often difficult to diagnose. Some common signs and symptoms of histamine intolerance include:
· Difficulty falling asleep and easily aroused
· High blood pressure
· Vertigo, dizziness
· Arrhythmia, accelerated heart rate
· Difficulty regulating body temperature
· Nausea, vomiting
· Stomach cramps
· Nasal congestion, sneezing, breathing difficulties
· Abnormal menstrual cycle
· Tissue swelling
As stated earlier, the enzyme DAO is essential to break down ingested histamine in the body and if you are deficient in this enzyme, symptoms of histamine intolerance are likely. You may be wondering, what causes DAO deficiency or low DAO? Some examples include:
· Gluten intolerance
· Leaky Gut
· DAO-blocking foods: alcohol, energy drinks, and tea
· Genetic mutations (common in people of Asian-descent)
· Inflammation from Crohn’s Disease, ulcerative colitis, and inflammatory bowel disease
· Commonly Used Medications:
o Non-steroidal anti-inflammatory drugs (ibuprofen, aspirin)
o Antidepressants (Cymbalta, Effexor, Prozac, Zoloft)
o Immune modulators (Humira, Enbrel, Plaquenil)
o Antiarrhythmics (propanolol, metaprolol, Cardizem, Norvasc)
o Antihistamines (Allegra, Zyrtec, Benadryl)**
o Histamine (H2) blockers (Tagamet, Pepcid, Zantac)**
· Antihistamines and Histamine (H2) blockers? What? I know that may sound funny, and though these do help relieve your symptoms, they actually do decrease the levels of DAO in your body.
If you are feeling that this may sound like you, a test for histamine intolerance should be performed. There are a few ways to do this:
o This includes eliminating the “high histamine” foods for 30 days, then reintroducing them one by one. This should be done using an elimination/reintroduction guideline.
· Blood Testing
o Many people do not like getting their blood drawn, but it could be a helpful way to see if you have a DAO deficiency. Testing for both DAO and histamine should be done. If your ratio of histamine/DAO is high, it means you are ingesting excess histamine and are lacking the DAO to break it all down.
· Trial of DAO
o Testing may be cumbersome or expensive, and an elimination diet may be daunting. If this sounds like you, try a low histamine diet and purchase a DAO supplement. Take your DAO supplement with every meal, and if your symptoms go away, low DAO could be the culprit of your symptoms.
Once you find that you are in fact histamine intolerant, you will probably want to treat it to feel better right? To do that, you will want to remove foods high in histamine for 1-3 months. Also, take two DAO supplement pills at each meal. Above all, it is crucial that you find the root cause of the histamine intolerance, which could be a number of things. Maybe a medication you are taking is causing the intolerance; work with your doctor to wean off or stop taking that medication. If it is caused by a problem in your gastrointestinal tract, it is crucial to heal it. Once your gut is healed, DAO supplementation can be stopped and you will be able to reintroduce histamine-containing foods in your diet.
For more information about histamine intolerance and its causes, reading 15 Signs of Histamine Intolerance by Dr. Amy Myers may be helpful in filling the gaps not covered here. You can find this here.