Turmeric Increases Urinary Oxalate Levels

LARAMIE, Wyo.— Consumption of supplemental doses of turmeric can significantly increase urinary oxalate levels, thereby increasing risk of kidney stone formation in susceptible individuals (Am J Clin. Nutr. 2008;87(5):1262-67). In the eight-week, randomly-assigned, crossover study, 11 healthy subjects, aged 21 to 38 years, ingested supplemental doses of cinnamon and turmeric for four-week periods with 55 mg of oxalate/d. Oxalate load tests, which entailed the ingestion of a 63-mg dose of oxalate from the test spices, were performed after each four week experimental period and at the study onset with water only (control treatment). Compared with the cinnamon and control treatments, turmeric ingestion led to a significantly higher urinary oxalate excretion during the oxalate load tests. There were no significant changes in fasting plasma glucose or lipids in conjunction with the four week periods of either cinnamon or turmeric supplementation. The percentage of oxalate that was water soluble differed markedly between cinnamon (6 percent) and turmeric (91 percent), which appeared to be the primary cause of the greater urinary oxalate excretion/oxalate absorption from turmeric.