Dietary oxalate and kidney stone formation

Abstract

Dietary oxalate is plant-derived and may be a component of vegetables, nuts, fruits, and grains. In normal individuals, approximately half of urinary oxalate is derived from the diet and half from endogenous synthesis. The amount of oxalate excreted in urine plays an important role in calcium oxalate stone formation. Large epidemiological cohort studies have demonstrated that urinary oxalate excretion is a continuous variable when indexed to stone risk. Thus, individuals with oxalate excretions >25 mg/day may benefit from a reduction of urinary oxalate output. The 24-h urine assessment may miss periods of transient surges in urinary oxalate excretion, which may promote stone growth and is a limitation of this analysis. In this review we describe the impact of dietary oxalate and its contribution to stone growth. To limit calcium oxalate stone growth, we advocate that patients maintain appropriate hydration, avoid oxalate-rich foods, and consume an adequate amount of calcium.

Characteristics of the urinary microbiome in kidney stone patients with hypertension

“…The KSD-NTN group also had a higher level of Firmicutes and a higher level of the associated genus Lactobacillus. Lactobacillus can decrease the excretion of urinary oxalate [34], which is responsible for the formation of KSD [35]. Thus, the increase in probiotic bacteria such as Lactobacillus accompanying the increase in pathogenic bacteria in the KSD-NTN group (compared to the HC group) might be a self-protective response in the urinary microbiome.…”

Dietary Oxalate Intake and Kidney Outcomes

“…Chan School of Public Health Nutrition Department and this may be a valid asset either for determining patients with a very high oxalate intake and for reducing dietary oxalate intake in subjects at risk [84]. The non-linear association between dietary and urinary oxalate content was recently shown by Mitchell et al There is a 2.7 mg increase in urinary oxalate excretion for every 100 mg of oxalate consumption, within a range of 50-750 mg/day and on a 1000 mg/day calcium diet [79]. However, even when dietary oxalate intake is lower than 50 mg/day, it significantly contributes to urinary oxalate excretion.…”

“…Dietary oxalate intake is one of the modifiable risk factors of hyperoxaluria [79]. Although not without limitations, 24 h urine collection is the most common method for estimating daily oxalate consumption and absorption [1].…”

Statins significantly alter urinary stone‐related urine biochemistry in calcium kidney stone patients with dyslipidemia

“…The second important and unanswered finding derived from the current study is that urine oxalate significantly increased after statin use. Previous literature suggested that >50% of urine oxalate comes from endogenous hepatic production and the reminder variably comes from the diet 29 . One of the most common adverse effects of statin is hepatic dysfunction.…”