Urinary Excretion of Histamine, Methylhistamine and Methylimidazoleacetic Acids in Man under Standardized Dietary Conditions

Abstract

A diet almost lacking histamine and bacteria has been given to twenty normal human subjects and histamine, methylhistamine and methylimidazoleacetic acids have been measured in the urine. The diet regimen resulted in a rather constant urinary excretion of the main histamine metabolite, 1,4-MeImAA (range 1.7–4.5 mg/24 hrs), also in subjects which previously had shown high and variable values. Cigarette smokers had higher values. The effect of inhibition of diamine oxidase with aminoguanidine was also studied in ten of the subjects under these standardized dietary conditions. An obvious increase in urinary methylhistamine and a small increase in 1,4-MeImAA was found. It is suggested that this diet can be used to diminish dietary influences in studies of histamine metabolism in man.

Key-words:

• Aminoguanidine
• diet
• histamine metabolism in man
• smoking