Effects of orotic acid ingestion on urinary and blood parameters in humans

Pertinent urinary and blood parameters were examined in 29 normal adults ingesting orotic acid by capsule once a week. Upon ingestion of 6 g orotic acid, urinary excretion of orotate and urate was increased in all subjects but creatinine and urea were unaffected. Mean orotate excretion was 624 mg or 10.5% of dose ingested, although individual variability was large (1–26%). In five persons studied more extensively, excretion of excess orotate was proportional to the amount ingested and was generally complete within 8 hours. Orotic acid ingestion led to uricosuria and the pattern for urate excretion was similar to that for orotate. Blood parameters before participation in the study and 24 hours after ingesting 6 g orotic acid were within normal ranges. However, serum urate and cholesterol were decreased significantly. The decrease in blood urate reflects the uricosuric effect of orotic acid. The hypocholesteremic response to orotic acid ingestion in humans warrants further investigation.