Urinary organic acids in man. II. Effects of individual variation and diet on the urinary excretion of acidic metabolites.

We have assessed individual variations in urinary acidic metabolite excretion and the effects of extreme alterations in dietary composition on these metabolites in selected normal persons who we considered representative of the general ambulant normal population. Extreme dietary alterations produced relatively small changes in the patterns or amounts of metabolite excretion, but large individual within-subject variations were observed. Our results indicate that variation in the ranges of excretion for the normal population mainly depend on individual metabolic variations rather than on dietary factors, and provide a basis for the assessment of the normal ranges determined from population surveys. Our results are discussed in relation to previous studies on the variability of urinary acidic metabolite excretion in man.