warum vertrage ich keinen kaffee mehr — can a DNA test help?

The question of why you suddenly can't tolerate coffee is complex and usually multifactorial. A DNA test can only provide a partial answer. Caffeine is primarily metabolized by the CYP1A2 enzyme in the liver. Genetic variants (e.g., rs762551) determine whether you are a fast or slow caffeine metabolizer. Slow metabolizers have a higher risk of cardiovascular side effects and sleep disturbances with high intake. The COMT gene (rs4680) also plays a role: carriers of the Val variant break down dopamine and adrenaline faster, which can blunt the stress response to caffeine; the Met variant may lead to greater tension. However, these genes explain only part of individual tolerance. Acquired factors are often more important: changes in liver function, medication use (e.g., antibiotics, oral contraceptives), hormonal shifts (pregnancy, menopause), gastrointestinal issues, or gut dysbiosis. A sudden intolerance can also signal liver stress or gastric irritation. A DNA test can offer clues about your genetic predisposition, but it does not replace a medical workup. If you suddenly cannot tolerate coffee, you should investigate other causes like medications, stress, or organic problems. The evidence for the utility of genetic tests in coffee intolerance is moderate – they provide mechanistic insights but not a clinical diagnosis.