Public Release: 

Reducing salt intake may help protect kidney patients' heart and kidney health

American Society of Nephrology

Highlights

  • In patients with chronic kidney disease, dietary sodium restriction reduced albuminuria (an indicator of kidney dysfunction) and blood pressure, whereas paricalcitol (a vitamin D receptor activator) in itself had no significant effect on these measures.

  • The combination of paricalcitol and a low sodium diet resulted in the lowest albuminuria levels in patients.

Washington, DC (November 17, 2016) -- New research indicates that reducing sodium intake may provide kidney and heart benefits for patients with chronic kidney disease (CKD). The findings appear in an upcoming issue of the Journal of the American Society of Nephrology (JASN).

Urinary excretion of proteins, including albumin, is a hallmark of CKD. Therapies that reduce such albuminuria can slow kidney function decline and also have beneficial effects on the heart and blood vessels. Unfortunately, currently available therapies do not eliminate albuminuria in many patients, leaving these individuals with what is known as residual albuminuria.

A team led by Martin de Borst, MD, PhD (University Medical Center Groningen, in The Netherlands) studied 2 interventions that have demonstrated potential for reducing residual albuminuria: dietary sodium restriction and a drug (paricalcitol) that activates the vitamin D receptor. In a randomized trial that included 45 patients with CKD, each intervention was added to an optimized conventional treatment regimen during four 8-week periods.

The investigators found that dietary sodium restriction led to a significant reduction of residual albuminuria and blood pressure, whereas paricalcitol had no significant effect on these measures. The combination of paricalcitol and a low sodium diet, however, resulted in the lowest albuminuria levels.

"What we found was that sodium restriction provided a relatively large beneficial effect, whereas the effect of paricalcitol was small. Thus, the impact of the combined intervention was largely due to the protective effect of sodium restriction," said Dr. de Borst.

Most people consume twice as much sodium as the 2 grams per day recommended by the World Health Association. "In our study, patients consumed on average 4 grams of sodium per day, which is well in line with global trends in sodium consumption among CKD patients," said Dr. de Borst. "Interestingly, following our intervention aimed at reduced sodium intake, patients consumed 2.5 grams per day, which is still above the recommended level. This moderate restriction resulted in a strong reduction in albuminuria and blood pressure, indicating that even a moderate reduction in sodium intake may provide serious health benefits."

###

Study co-authors include Charlotte A. Keyzer, MD, PhD, G. Fenna van Breda, MD, Marc G. Vervloet, MD, PhD, Maarten A. de Jong, MD, Gozewijn D. Laverman, MD, PhD, Marc H. Hemmelder, MD, PhD, Wilbert M.T. Janssen, MD, PhD, Hiddo J. Lambers Heerspink, PhD, Arjan J. Kwakernaak, MD, PhD, Stephan J.L. Bakker, MD, PhD, Gerjan Navis, MD, PhD and Martin H. de Borst, MD, PhD for the Holland Nephrology Study (HONEST) Network.

The main findings of the study are summarized for a general audience in the following animation: http://tiny.cc/cg8mdb

Disclosures: The study was financially supported by the Dutch Kidney Foundation (grant nos. KJPB.08.07 and CP10.11). AbbVie provided the study medication (paricalcitol and placebo). The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.

The article, entitled "The effect of vitamin D receptor activation and dietary sodium restriction on residual albuminuria in chronic kidney disease: the ViRTUE-CKD randomized controlled trial," will appear online at http://jasn.asnjournals.org/ on November 17, 2016; doi: 10.1681/ASN.2016040407.

The content of this article does not reflect the views or opinions of The American Society of Nephrology (ASN). Responsibility for the information and views expressed therein lies entirely with the author(s). ASN does not offer medical advice. All content in ASN publications is for informational purposes only, and is not intended to cover all possible uses, directions, precautions, drug interactions, or adverse effects. This content should not be used during a medical emergency or for the diagnosis or treatment of any medical condition. Please consult your doctor or other qualified health care provider if you have any questions about a medical condition, or before taking any drug, changing your diet or commencing or discontinuing any course of treatment. Do not ignore or delay obtaining professional medical advice because of information accessed through ASN. Call 911 or your doctor for all medical emergencies.

Since 1966, the American Society of Nephrology (ASN) has been leading the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients. ASN has nearly 16,000 members representing 112 countries. For more information, please visit http://www.asn-online.org or contact us at 202-640-4660.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.