Histamine plays a major role in the immune response for allergies, as well as various other purposes in other body systems. The compound is involved in least 23 physiological functions. The body can synthesize histamine in all tissues, but the lungs, skin, and gastrointestinal tract contain the most histamine. One of the most widely understood functions of histamine is the role it plays in allergic reactions. Researchers believe that the allergic process has two phases: early and late. Within seconds or minutes of allergen exposure, the body releases histamines. This begins the early phase of an allergic response. Different areas of the body have different histamine receptor proteins. Depending on which receptor proteins histamine interacts with, a variety of allergic and inflammatory responses can occur, such as: itching, sneezing, coughing, and watering eyes. Diamine Oxidase (DAO) also known as histaminase, is involved in the metabolism, oxidation, and inactivation of histamine. In some individuals, their levels of DAO are somehow inhibited, or just low, resulting in a Histamine Intolerance . DAO blockers: Alcohol. Black tea Energy drinks. green tea Mate tea Symptoms that can occur with Histamine Intolerance: • Rashes, Hives or Eczema 
• Headaches or migraines 
• Diarrhea 
• Low blood pressure 
• Itchy eyes/runny nose/congestion 
• Premenstrual cramping or headaches Four different histamine receptors are present across different cell types. Each works through different signaling mechanisms, which is why histamine has such diverse effects. H1 Found in smooth muscles and endothelial cells, like those that line the interior surface of blood vessels, and organs. It is responsible for acute allergic responses. H2 Found in the gastric parietal cells, stomach & is involved in the secretion of gastric acid. H3 Present in the cells of the central nervous system & helps modulate neurotransmission. H4 Appear in mast cells, T cells, dendritic cells, and eosinophils. Its purpose is regulating immune responses. High histamine level foods: Alcohol Strawberries Pickled or canned foods sauerkrauts walnuts, cashew nuts Vinegar Matured cheeses Smoked meat products salami, ham, sausages. Shellfish Beans and pulses – chickpeas, soybeans, peanuts Chocolates and other cocoa based products Processed meals Salty snacks sweets with preservatives or artificial colorings Histamine liberators (release/free up) : Most citric fruits kiwi, lemon, lime pineapple plums Papaya Tomatoes Nuts. Cocoa & chocolate. Beans and pulses. Wheat germ Additives – benzoate, sulphites, nitrites, glutamate, food dyes Low histamine level foods: Fresh meat, fish & Chicken (skinless). Fresh pasteurized milk & milk products. Egg yolk Cream cheese, butter (without the histamine generating rancidity) Fresh fruits (except citrus & strawberries) are considered to have a low histamine level as do Fresh vegetables, except tomatoes Grains – rice noodles, yeast free rye bread, rice crisp bread, oats, puffed rice crackers, millet flour, pasta (spelt and corn based) Milk substitutes – coconut milk, rice milk Most cooking oils Most leafy herbs – Most non-citric fruit juices- Herbal teas Here are some general pointers: Avoid or reduce eating canned foods and processed meals Avoid or reduce eating ripened and fermented foods (older cheeses, alcoholic drinks, products containing yeast, stale fish) Histamine levels in foods vary, depending on how ripe, matured or clean the foods are As much as it is possible, only buy and eat fresh products Don’t allow foods to linger outside the refrigerator – especially meat products Ensure that your food preparation area (kitchen) is always kept clean – but don’t be manic!
