warum vertrage ich keinen kaffee mehr — what are common causes?

Sudden coffee intolerance can stem from several causes. A common one is genetic variation in the CYP1A2 gene, which affects how fast you metabolize caffeine. Slow metabolizers may experience jitters, insomnia, or palpitations. Coffee's acidity can also irritate the stomach or worsen reflux. Additives like milk (lactose intolerance) or artificial sweeteners may trigger symptoms. Age, hormonal changes (e.g., menopause), or liver function can alter tolerance. Evidence is moderate: genetic studies support CYP1A2's role, but many factors are individual. A DNA test can offer clues but is not diagnostic. Caveat: sudden intolerance warrants medical evaluation to rule out underlying conditions.