Dataset Information

Hypercalciuria associated with high dietary protein intake is not due to acid load.

ABSTRACT:

Context and objective

Dietary intake of animal proteins is associated with an increase in urinary calcium and nephrolithiasis risk. We tested the hypothesis that the acid load imposed by dietary proteins causes this hypercalciuria.

Design and setting

In a short-term crossover metabolic study, an alkali salt was provided with a high-protein diet (HPD) to neutralize the acid load imparted by dietary proteins.

Participants and interventions

Eleven healthy volunteers were evaluated at the end of each of four phases while consuming metabolic diets with fixed calcium and sodium content. Phases 1 and 3 consisted of a control diet (CD). Phases 2 and 4 consisted of a eucaloric HPD (60 g/d animal proteins added to CD). Along with HPD in phases 2 and 4, subjects ingested 30 mEq twice daily of either potassium citrate (KCitrate, alkaline salt) or potassium chloride (KCl, control neutral salt).

Results

KCitrate completely neutralized the acid load imparted by HPD (based on changes in urine pH and net acid excretion) and increased urinary citrate. Urinary calcium increased during both HPD phases compared with CD but was not significantly different between the HPD + KCl and HPD + KCitrate phases (182 ± 85 vs. 170 ± 85 mg/d; P = 0.28). Increased urinary saturation with respect to calcium oxalate and uric acid with HPD was abrogated by KCitrate.

Conclusions

This study suggests that, at least in the short-term, mechanism(s) other than acid load account for hypercalciuria induced by HPD. The beneficial effect of KCitrate on nephrolithiasis risk with HPD is through correction of declines in urine pH and citrate.

SUBMITTER: Maalouf NM

PROVIDER: S-EPMC3232614 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

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Publications

Hypercalciuria associated with high dietary protein intake is not due to acid load.

Maalouf Naim M NM Moe Orson W OW Adams-Huet Beverley B Sakhaee Khashayar K

The Journal of clinical endocrinology and metabolism 20111005 12

<h4>Context and objective</h4>Dietary intake of animal proteins is associated with an increase in urinary calcium and nephrolithiasis risk. We tested the hypothesis that the acid load imposed by dietary proteins causes this hypercalciuria.<h4>Design and setting</h4>In a short-term crossover metabolic study, an alkali salt was provided with a high-protein diet (HPD) to neutralize the acid load imparted by dietary proteins.<h4>Participants and interventions</h4>Eleven healthy volunteers were evalu ...[more]

PMID: 21976719

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Project description:Background and objectivesProtein and potassium intake and the resulting diet-dependent net acid load may affect kidney stone formation. It is not known whether protein type or net acid load is associated with risk of kidney stones.Design, setting, participants, & measurementsWe prospectively examined intakes of protein (dairy, nondairy animal, and vegetable), potassium, and animal protein-to-potassium ratio (an estimate of net acid load) and risk of incident kidney stones in the Health Professionals Follow-Up Study (n=42,919), the Nurses' Health Study I (n=60,128), and the Nurses' Health Study II (n=90,629). Multivariable models were adjusted for age, body mass index, diet, and other factors. We also analyzed cross-sectional associations with 24-hour urine (n=6129).ResultsDuring 3,108,264 person-years of follow-up, there were 6308 incident kidney stones. Dairy protein was associated with lower risk in the Nurses' Health Study II (hazard ratio for highest versus lowest quintile, 0.84; 95% confidence interval, 0.73 to 0.96; P value for trend <0.01). The hazard ratios for nondairy animal protein were 1.15 (95% confidence interval, 0.97 to 1.36; P value for trend =0.04) in the Health Professionals Follow-Up Study and 1.20 (95% confidence interval, 0.99 to 1.46; P value for trend =0.06) in the Nurses' Health Study I. Potassium intake was associated with lower risk in all three cohorts (hazard ratios from 0.44 [95% confidence interval, 0.36 to 0.53] to 0.67 [95% confidence interval, 0.57 to 0.78]; P values for trend <0.001). Animal protein-to-potassium ratio was associated with higher risk (P value for trend =0.004), even after adjustment for animal protein and potassium. Higher dietary potassium was associated with higher urine citrate, pH, and volume (P values for trend <0.002).ConclusionsKidney stone risk may vary by protein type. Diets high in potassium or with a relative abundance of potassium compared with animal protein could represent a means of stone prevention.

Dataset Information

Hypercalciuria associated with high dietary protein intake is not due to acid load.

Context and objective

Design and setting

Participants and interventions

Results

Conclusions

Publications

Hypercalciuria associated with high dietary protein intake is not due to acid load.

Similar Datasets

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