Effect of cinnamon and turmeric on urinary oxalate excretion, plasma lipids, and plasma glucose in healthy subjects.
BACKGROUND
High oxalate intake resulting from consuming supplemental doses of cinnamon and turmeric may increase risk of hyperoxaluria, a significant risk factor for urolithiasis.


OBJECTIVE
This study assessed urinary oxalate excretion from supplemental doses of cinnamon and turmeric as well as changes in fasting plasma glucose, cholesterol, and triacylglycerol concentrations.


METHODS
Eleven healthy subjects, aged 21-38 y, participated in an 8-wk, randomly assigned, crossover study that involved the ingestion of supplemental doses of cinnamon and turmeric for 4-wk periods that provided 55 mg oxalate/d. Oxalate load tests, which entailed the ingestion of a 63-mg dose of oxalate from the test spices, were performed after each 4-wk experimental period and at the study onset with water only (control treatment). Fasting plasma glucose and lipid concentrations were also assessed at these time points.


RESULTS
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 4-wk periods of either cinnamon or turmeric supplementation.


CONCLUSIONS
The percentage of oxalate that was water soluble differed markedly between cinnamon (6%) and turmeric (91%), which appeared to be the primary cause of the greater urinary oxalate excretion/oxalate absorption from turmeric. The consumption of supplemental doses of turmeric, but not cinnamon, can significantly increase urinary oxalate levels, thereby increasing risk of kidney stone formation in susceptible individuals.
Tang
Minghua
M
Department of Family and Consumer Sciences, University of Wyoming, Laramie, WY 82071, USA.
Larson-Meyer
D Enette
DE
Liebman
Michael
M
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D002935:Cinnamomum zeylanicum / Q000737:chemistry; D003404:Creatinine / Q000652:urine; D018592:Cross-Over Studies; D030024:Curcuma / Q000737:chemistry; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D008055:Lipids / Q000097:blood*; D008297:Male; D010070:Oxalates / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000652:urine*; D012995:Solubility; D052878:Urolithiasis / Q000453:epidemiology / Q000209:etiology
D001786:Blood Glucose; D008055:Lipids; D010070:Oxalates; D003404:Creatinine