Is Histamine Keeping You Awake?

Histamine plays an important role in the body. It can affect blood pressure, digestion and helps your body fight allergens. It also affects our circadian rhythms and how well we sleep. Interestingly, how well we sleep also affects histamine levels. Histamine has a pivotal role in the regulation of sleep-wakefulness.

What Is Histamine?

Histamine is a chemical involved in your immune system, proper digestion, and your central nervous system.

Histamine is produced in the brain in higher concentrations during the day, which keeps us awake and alert.
Levels fall at night. If histamine production is stimulated at night, as is sometimes the case when you get mosquitoes or insect bites, it not only itches, but can keep you awake. Obviously if you’ve just been bitten it may itch but your body will now produce histamine, which is a daytime hormone, keeping us awake and alert.

Histamine is involved in immune and inflammatory responses, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain. The human body has histamine receptors all over the body: the heart, breasts, lungs, and brain.

The Role Of Histamine In Sleep Wake Stability

The hypothalamus is an important region in the brain that is responsible for the sleep wake cycle and circadian rhythms. Histamine is found here and is responsible for wakefulness. It activates cortical neurons and wake promoting neurons outside of the hypothalamus; serotonin, dopamine and acetylcholine. Histamine It can also increase levels of noradrenaline which increase blood pressure, getting the body ready for action. Histamine also inhibits sleep promoting neurons.

Narcolepsy is a neurological disorder. People with this condition go straight into REM sleep and it usually lasts for a few minutes. People with this condition are thought to have low levels of the excitatory neurotransmitter histamine, which wakes us up.

In the gut, histamine helps to produce stomach acid and helps with digestion.

In the immune system, histamine is released by mast cells (white blood cells that make up a good chunk of the immune system) when we’re injured or infected with something nasty.

Histamine Intolerance

In healthy individuals, histamines are primarily broken down by the N-methyltransferase (HMT) enzyme in the central nervous system and the diamine oxidase enzyme (DAO) in the gut.

The histamine build-up is what gives you a headache and leaves you feeling flushed, itchy and miserable. This is part of the body’s natural immune response, but you also need to break down histamine. If you don’t break down histamine properly, you may develop histamine intolerance. The DOA enzyme is the primary enzyme for breaking down ingested histamine in the gut.

Improper or insufficient synthesis of histamine can lead to somnolence (excessive sleepiness), while excess histamine can lead to insomnia, a common problem among people who suffer from histamine intolerance. Avoiding high-histamine foods, especially later in the day, might lead to a better night’s sleep for those with a histamine intolerance.

Skin issues like eczema, hives, itching, headaches, migraines, vertigo, difficulty sleeping, irregular menstrual cycles and low blood pressure are other signs of histamine intolerance.

histamine reactions

What Causes High Histamine Levels?

Small intestinal bacterial overgrowth (SIBO) disrupt the enzymes that break down histamine. Bacteria in SIBO can produce histamine aswell.  You can also have a deficiency in DAO, gluten intolerance, inflammatory conditions in the gut and medication can also disrupt DOA. Antihistamines can also block the breakdown of histamine.

  • Allergies (IgE reactions)
  • Diamine Oxidase (DAO) deficiency (enzyme that breaks down histamine)

Histamine-rich foods:

  • Fermented alcohol like wine, champagne, and beer
  • Vinegar-containing foods: pickles, mayonnaise, olives
  • Soured foods: sour cream, sour milk, buttermilk, soured bread, etc
  • Fermented foods: sauerkraut, vinegar, soy sauce, kefir, yogurt, kombucha, etc

Histamine-Releasing Foods:

  • Alcohol
  • Bananas
  • Chocolate
  • Cow’s Milk
  • Nuts
  • Papaya
  • Pineapple
  • Shellfish
  • Strawberries
  • Tomatoes
  • Wheat Germ
  • Many artificial preservatives and dyes

Avoid high histamine foods: Vinegar containing foods, sour foods, fermented foods, aged meats and cheeses, alcohol (especially wine), most citrus fruits, dry fruit, avocados, smoked foods and add in a DAO supplement.

Reduce stress, reduce inflammatory and high histamine foods, reduce heavy metals and environmental toxins.

Eliminate and Reintroduction of Histamine Foods

Elimination diets are the gold standard for identifying food intolerances, sensitivities and allergies through diet. Remove problematic foods for 30 days and reintroduce them one at a time, while testing for symptoms.

Medications and Sleep

Medications being taken or substances being used, such as alcohol can also cause sleep problems. They may block parts of your sleep cycles or disable the natural onset of the different sleep phases and cause fragmented sleep.

For example, according to the National Sleep Foundation, some medications, including those for high blood pressure and asthma, can keep you up all night, while others, like cough, cold, and flu medications, can disrupt sleep. And certain medications, such as antihistamines, can cause daytime drowsiness. In fact, sleepiness is one of the most common side effects of medications.

Why do we take Antihistamines Medications?

Antihistamines are medicines that calm down allergy systems. The immune system will raise its defenses every time it detects the presence of the offending substance, or allergen. IgE reactions to food or environmental allergens causes the immune system’s antibodies pick up an allergen molecule and carries it to a white blood cell called mast cells, which trigger the release of histamine. While pollen, pet dander and dust may seem harmless, your immune systems sees them as a threat. This also applies to a food allergy and triggers an allergic reaction in your gut.

We take antihistamines to help reduce congestion, sneezing, coughing, and allergy symptoms but it also affects our sleep. They block the receptors that respond to histamine. Using antihistamines, reduces histamine in the brain and that’s why we feel drowsy sometimes. In fact, most medications marketed as sleep aids contain an antihistamine for this reason.

Other over-the-counter (OTC) medicines that can contribute to sleep problems are cough, cold, and flu medications that contain alcohol, that prevent REM sleep and headache and pain medications that contain caffeine. Many prescribed or over the counter medications can interfere with sleep as a side effect. Sleepiness is one of the most common side effects of medications including antihistamines.


What To Know About Histamine Intolerance & Eating A Low-Histamine Diet

Amy Myers – All About Histamine Intolerance

How Medicines can Affect Sleep


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