Tammera Karr, PhD, BCHN™, CNW®, CDSP®
Leena S. Guptha, ND, DO, PhD, MBA, MS
Pacific College of Health and Science, and the National Association of Nutrition Professionals
Abstract Approved: February 8, 2023 This literature review explores dietary oxalates role in the development of chronic inflammatory kidney disease in middle age and older individuals. The authors pose the following questions: Is oxalate produced endogenously? If food sources contribute to chronic kidney disease and inflammation, what are those foods? What role does cultural food preparation and cooking play in denaturing food oxalates? Oxalates are not limited to edible plants; normal human metabolic processes of breaking down ascorbic acid may create up to 30 mg of oxalate per day. Research supports urolithiasis as a common urologic disease in industrialized societies. Approximately 80% of kidney stones are calcium oxalate resulting in hyperoxaluria. Endogenous oxalate sources include ascorbic acid, amino acids, and glyoxal metabolism. Additional research estimates the daily endogenous production of oxalate to be 10–25 mg, and suboptimal colonization of oxalate-degrading bacteria and malabsorptive disease are also contributing factors to the development of kidney disease. Oxalate transcellular processes rely on multifunctional anion exchangers and are being investigated though poorly understood. A review of research revealed dietary inclusion of foods high in oxalate: spinach, strawberries, raspberries, beets, rhubarb, tea, nuts, wheat bran, chocolate, sorrel, sesame, carambola, amaranth, almonds, soya bean, and coffee could contribute approximately 50–80% of the urinary oxalate in compromised individuals with liver glycation, bacterial insufficiencies, malabsorption and anion exchange challenges. Traditional cooking processes were found to reduce food oxalate levels 30-40%. Juicing of raw foods increased oxalate levels. Food combined with red and white wine provides protective compounds reducing epithelial damage to renal function. If there is a family history of kidney stones, foods high in oxalates may be eaten in moderation providing calcium intake is adequate, as it helps decrease the absorption of oxalates from the meal ingested.