Modern Western diets, with higher contents of animal compared to fruits and vegetable products, have a greater content of acid precursors vs. base precursors, which results in a net acid load to the body. To prevent inexorable accumulation of acid in the body and progressively increasing degrees of metabolic acidosis, the body has multiple systems to buffer and titrate acid, including bone which contains large quantities of alkaline salts of calcium. Both in vitro and in vivo studies in animals and humans suggest that bone base helps neutralize part of the dietary net acid load. This raises the question of whether decades of eating a high acid diet might contribute to the loss of bone mass in osteoporosis. If this idea is true, then additional alkali ingestion in the form of net base-producing foods or alkalinizing salts could potentially prevent this acid-related loss of bone. Presently, data exists that support both the proponents as well as the opponents of this hypothesis. Recent literature reviews have tended to support either one side or the other. Assuming that the data cited by both sides is correct, we suggest a way to reconcile the discordant findings. This overview will first discuss dietary acids and bases and the idea of changes in acid balance with increasing age, then review the evidence for and against the usefulness of alkali therapy as a treatment for osteoporosis, and finally suggest a way of reconciling these two opposing points of view.

Acid retention associated with reduced glomerular filtration rate (GFR) exacerbates nephropathy progression in partial nephrectomy models of chronic kidney disease (CKD) and might be reflected in patients with CKD with reduced estimated GFR (eGFR) by increased anion gap (AG). We explored the presence of AG and its association with CKD in 14,924 adults aged ≥20 yr with eGFR ≥ 15 ml·min⁻¹·1.73 m⁻² enrolled in the National Health and Nutrition Examination Survey III, 1988–1994, using multivariable regression analysis. The model was adjusted for sociodemographic characteristics, diabetes, and hypertension. We further examined the association between AG and incident end-stage renal disease (ESRD) using frailty models, adjusting for demographics, clinical factors, body mass index, serum albumin, bicarbonate, eGFR, and urinary albumin-to-creatinine ratio by following 558 adults with moderate CKD for 12 yr via the United States Renal Data System. Laboratory measures determined AG using the traditional, albumin-corrected, and full AG definitions. Individuals with moderate CKD (eGFR: 30–59 ml·min⁻¹·1.73 m⁻²) had a greater AG than those with eGFR ≥ 60 ml·min⁻¹·1.73 m⁻² in multivariable regression analysis with adjustment for covariates. We found a graded relationship between the adjusted mean for all three definitions of AG and eGFR categories ( P trend < 0.0001). During followup, 9.2% of adults with moderate CKD developed ESRD. Those with AG in the highest tertile had a higher risk of ESRD after adjusting for covariates in a frailty model [relative hazard (95% confidence interval) for traditional AG: 1.76 (1.16–2.32)] compared with those in the middle tertile. The data suggest that high AG, even after adjusting for serum bicarbonate, is a contributing acid-base mechanism to CKD progression in adults with moderate chronic kidney disease.

Background: The association between fruit and vegetable (FV) intake and the risk of end-stage kidney disease (ESKD) has not been examined in the general population and fully explored in chronic kidney disease (CKD). We prospectively evaluated this relationship in US representative sample of adults and evaluated consistency by the presence or absence, and severity, of CKD. Methods: We used data from the Third National Health and Nutrition Examination Survey (1988–1994) linked with the US Renal Data System, including 14,725 adults aged ≥20 years and with follow-up for ESKD through 2008. Daily FV intake was ascertained using a food frequency questionnaire. We examined the association between selected categories of FV intake and ESKD using a Fine Gray competing risk model adjusting for sociodemographics, lifestyle, clinical and nutritional factors, estimated glomerular filtration rate, and albuminuria. We evaluated whether risk varied in individuals with severe versus any CKD. Results: 230 participants (1.5%) developed ESKD during follow-up. In the adjusted model, compared to highest intake, those in lowest categories of FV intake had a higher risk of ESKD, for <2 times/day (1.45 [1.24–1.68], 2 to <3 times/day (1.40 [1.18–1.61]), 3 to <4 times/day (1.25 [1.04–1.46]), and 4 to <6 times/day (1.14 [0.97–1.31]). There was suggestion of heterogeneity (p for interaction = 0.03) with possible stronger inverse association in patients with CKD than those without CKD. After stratification, we obtained similar strong inverse association when we examined ESKD incidence across intake of FVs in participants with CKD stages 1–4 (n = 5,346) and specifically in those with CKD stages 3–4 (n = 1,084). Conclusions: Low intake of FVs was associated with higher risk of ESKD in US adults with and without CKD, supporting an emerging body of literature on the potential benefits of plant-rich diets for prevention of ESKD.

Chronic kidney disease (CKD) is common and is associated with excess mortality and morbidity. Better management could slow progression of disease, prevent metabolic complications, and reduce cardiovascular outcomes. Low patient awareness of CKD and ineffective patient-provider communication can impede such efforts. We developed provider and patient-directed interventions that harness health information technology to enhance provider recognition of CKD and delivery of guideline concordant care and augment patient understanding and engagement in CKD care. We report the design and protocol of the Kidney Awareness Registry and Education (KARE) Study, a 2x2 factorial randomized controlled trial that examines the impact of a multi-level intervention on health outcomes among low-income English, Spanish and Cantonese-speaking patients with CKD in a safety net system. The intervention includes: (1) implementation of a primary care electronic CKD registry that notifies practice teams of patients’ CKD status and employs a patient profile and quarterly feedback to encourage provision of guideline-concordant care at point-of-care and via outreach; and (2) a language-concordant, culturally-sensitive self-management support program that consists of automated telephone modules, provision of low-literacy written patient-educational materials and telephone health coaching. The primary outcomes of the trial are changes in systolic blood pressure (BP) and the proportion of patients with BP control (≤140/90 mmHg) after one year. Secondary outcomes include patient understanding of CKD, participation in healthy behaviors, and practice team delivery of guideline-concordant CKD care. Results from the KARE study will provide data on the feasibility, effectiveness, and acceptability of technology-based interventions that support primary care efforts at improving health outcomes among vulnerable patients with CKD. ClinicalTrials.gov, number: NCT01530958