[The influence of different diets and smoking on the clinical chemical diagnosis of pheochromocytoma, neuroblastoma, and carcinoid syndrome (author's transl)].

The interference of various foodstuffs on methods to determine epinephrine (E), norepinephrine (NE), vanillylmandelic acid (VMA), metanephrines (MN), homovanillic acid (HVA), and 6-hydroxyindole acetic acid (5-HIA) in the 24 h urine for diagnosis of pheochromocytoma and carcinoid syndrome, respectively, was investigated. The foodstuffs included were: tea, coffee, almonds, pineapples, cheese, walnuts, vanilla pudding, bananas, tomatoes, and chocolate. Further, the interference of cigarette smoking on the determination of E, NE, VMA, and MN was also investigated. Walnuts caused a rather high elevation of 5-HIA in the urine. After eating bananas elevated excretion of E, NE, VMA, MN, and 5-HIA was observed. Small increases of the MN values were noticed after coffee and pineapples. Smoking of 20-30 cigarettes/day had no influence on the variables measured. If the methods described are used, thus, only bananas and walnuts have to be restricted some days before and during urine sampling, but not coffee and pineapples if consumed in the usual small quantities. There is no reason to insist on diet restriction except for bananas and walnuts.