What are the cause of excessive histamine or insufficient DAO

The main causes of excessive histamine or insufficient diamine oxidase (DAO) enzyme, leading to histamine intolerance, are:
  1. Gastrointestinal disorders: Various gastrointestinal conditions like inflammatory bowel disease (IBD), leaky gut syndrome, and bacterial overgrowth in the small intestine can impair DAO production or activity, resulting in reduced histamine breakdown.
  2. Genetic factors: Some individuals may have genetic mutations that lead to lower production or dysfunctional DAO enzymes, making it difficult to metabolize histamine effectively.
  3. Medications: Certain medications like antibiotics, antidepressants, antiarrhythmics, muscle relaxants, and NSAIDs can inhibit DAO activity or block histamine breakdown.
  4. Diet: Consuming foods rich in histamine (aged cheese, fermented foods, alcohol, etc.) can overwhelm the body's ability to break down histamine, leading to an accumulation.
  5. Intestinal barrier dysfunction: Impaired intestinal barrier function can allow increased absorption of histamine from the gut into the bloodstream, contributing to histamine overload.
  6. Bacterial overgrowth: An overgrowth of certain bacteria in the gut can lead to excessive production of histamine, overwhelming the DAO enzyme's capacity to break it down.
  7. Alcohol consumption: Alcohol can impair DAO activity and intestinal barrier function, leading to increased histamine absorption.
In summary, the primary causes of histamine intolerance involve factors that either increase histamine production/absorption or decrease the activity of the DAO enzyme responsible for breaking down histamine.
What is the difference between Acetylcysteine and NAC
Medication used to treat paracetamol overdose and mucus-related conditions
Trade Names
ACC 200, Acetadote, Fluimucil, Mucomyst, others
Routes of Administration
By mouth, intravenous, inhalation
Common Side Effects
Nausea, vomiting, redness, itching
Acetylcysteine and NAC (N-Acetylcysteine) are the same compound. They refer to the same molecule with the chemical formula C5H9NO3S. Some key points:
  • Acetylcysteine is the generic name for the compound.
  • NAC is an abbreviation that stands for N-Acetylcysteine, which is the systematic chemical name of the same compound.
  • They are not different substances - NAC is simply an acronym used to refer to the acetylcysteine molecule.
  • Acetylcysteine/NAC is a derivative of the amino acid cysteine. It is a acetylated form of cysteine that is more stable and better absorbed than cysteine itself.
  • It is used as a mucolytic agent to help break down mucus and as an antidote for acetaminophen (paracetamol) overdose due to its antioxidant properties.
So in summary, acetylcysteine and NAC are just two different ways of referring to the exact same chemical compound. NAC is simply the more common abbreviation used for N-acetylcysteine, which is the systematic name for acetylcysteine.
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