Histamines and the Role of the Gut Microbiome
Histamines and the Role of the Gut Microbiome
Histamines are chemical messengers (biogenic amines) that are essential for the immune system, digestion, and nerve signaling. While your body produces histamine, you also ingest it through food. It is important to know that not everyone needs to avoid histamine creating foods, just some people are more sensitive than others.
The Gut Microbiome's Role in Histamine Balance
The gut microbiome—the trillions of microorganisms living in your digestive tract—plays a critical role in regulating the amount of histamine in your body. This happens in two main ways:
Histamine Production: Certain types of bacteria in the gut, particularly strains of Gram-negative bacteria like Citrobacter freundii, possess an enzyme called histidine decarboxylase (HDC). This enzyme converts the amino acid histidine (found in protein-rich foods) into histamine. Overgrowth of these histamine-producing bacteria (HPB) can lead to higher systemic histamine levels.
Histamine Degradation (Breakdown): The body primarily relies on two enzymes to break down histamine:
Diamine Oxidase (DAO): This enzyme is produced in the digestive tract and is the main enzyme responsible for degrading ingested histamine in the small intestine.
Histamine N-methyltransferase (HNMT): This enzyme degrades histamine in the central nervous system and other body tissues.
If the gut microbiome is imbalanced (dysbiosis) and there is an overgrowth of histamine-producing bacteria, or if there are issues with DAO enzyme production, a person can experience an overload, leading to Histamine Intolerance (HIT).
Symptoms of Histamine Intolerance
When the body's capacity to degrade histamine is overwhelmed by the amount being produced or ingested, it can trigger a wide range of symptoms that mimic an allergy or inflammatory response:
Gastrointestinal: Diarrhea, abdominal pain, bloating, and discomfort.
Systemic/Neurological: Headaches, migraines, anxiety, and fatigue.
Skin/Respiratory: Hives, itching, flushing, and runny nose.
Balancing the gut microbiome to favor histamine-degrading species over histamine-producing ones is a key strategy in managing symptoms related to histamine intolerance.
The Connection to Food
Histamine levels in food increase when bacteria break down amino acids over time. This is why certain foods are high in histamine:
Fermented Foods: Contain a large number of histamine-producing microbes (e.g., sauerkraut, aged cheeses).
Leftovers: Histamine levels in cooked food, especially meat and fish, rise significantly the longer they are stored in the refrigerator.
Aged/Cured Foods: The aging process promotes histamine formation (e.g., cured meats, smoked fish).
For individuals with histamine intolerance, managing the dietary intake of histamine and supporting a healthy gut microbiome are equally important.
Foods and Drinks That May Inhibit DAO
Inhibiting the DAO enzyme can increase the total histamine burden in the body, as the histamine from food is not properly neutralized before absorption.
1. Alcohol 🍷
Alcohol is one of the most potent inhibitors of the DAO enzyme and is a common trigger for histamine intolerance symptoms.
Mechanism: Alcohol directly inhibits the function of the DAO enzyme.
Double Impact: Alcoholic beverages are often high in histamine themselves due to fermentation (especially red wine, beer, and champagne), creating a dual problem for sensitive individuals.
2. Certain Foods and Components
Specific foods contain compounds that are known to interfere with DAO activity:
Energy Drinks and Coffee: High levels of caffeine can inhibit DAO activity.
Black Tea and Green Tea: Certain polyphenols and catechins found in teas can inhibit DAO function.
Other Histamine-Releasing Foods: Some foods don't contain high histamine but trigger your body to release its own histamine (e.g., citrus fruits, chocolate, nuts, strawberries), adding to the overall histamine load that DAO must process.
Histamine Balance and the Gut Microbiome
To maintain proper histamine balance, the body needs an efficient breakdown system.
Role of DAO: The DAO enzyme, primarily produced in the intestinal lining, is the crucial defense against histamine absorbed from food.
Role of the Microbiome: A balanced gut microbiome is key for intestinal health, which supports DAO production. Conversely, dysbiosis (an imbalance of bacteria) or inflammation (such as from overgrowth of histamine-producing bacteria like Citrobacter freundii) can impair the gut lining and reduce DAO enzyme function.
When DAO is inhibited by factors like alcohol or certain food compounds, or when it's overwhelmed by histamine from the diet or HPB, the result is a buildup that can lead to systemic symptoms.
Foods High in Histamine 🚫
Histamine levels increase in foods through microbial action (aging, fermentation, spoilage).
CategoryHigh-Histamine Foods to Limit/AvoidRationale
Fermented & Aged Sauerkraut, yogurt, kefir, soy sauce, vinegar, aged cheeses, fermented soy products (tempeh, miso).Products are high in histamine-producing microbes.
Meats & Leftovers Aged, smoked, cured, or ground meats.
Leftovers stored in the refrigerator (histamine levels rise quickly after cooking).Histamine-producing bacteria multiply as protein-rich food ages.
Fish & Seafood Canned, smoked, or spoiled fish (tuna, mackerel, herring, shellfish).Histamine levels increase rapidly if the fish is not immediately frozen or consumed.
Vegetables Tomatoes, spinach, eggplant, avocado.These naturally contain higher levels of histamine or histamine-releasing compounds.
Beverages Alcohol (especially red wine and beer), black tea, green tea.Alcohol and caffeine directly inhibit the DAO enzyme, hindering histamine breakdown.
Other Chocolate/Cocoa, dried fruits, citrus fruits, nuts, certain spices.Contains histamine or is a histamine-releaser.
Foods That Support Histamine Breakdown & Balance
The goal is to promote a healthy gut environment that supports the production of the Diamine Oxidase (DAO) enzyme and reduces opportunistic, histamine-producing bacteria.
Support DAO Production
Foods rich in Copper, Vitamin C, and Vitamin B6 (cofactors for DAO).DAO is the main enzyme for breaking down ingested histamine in the gut.
Reduce Histamine LoadFreshly cooked or immediately frozen meat/fish/poultry.
Refined grains (vs. whole grains).
Fresh fruits (like apples and pears)
vegetables (like cabbage and potatoes).Eating foods at their lowest possible histamine level reduces the demand on DAO.
Promote Gut HealthEating a diverse, anti-inflammatory diet (such as the Mediterranean diet and the bean protocol).
Probiotics containing certain strains of Bifidobacterium and Lactobacillus.A healthy, balanced gut microbiome reduces inflammation and supports the integrity of the intestinal lining where DAO is made. Some probiotic strains have shown the ability to degrade histamine.
Avoid InhibitorsStrict avoidance of alcohol. Limiting caffeine and high-polyphenol teas (black and green tea).Prevents the direct inhibition of the crucial DAO enzyme.