10:51am Tuesday 22 October 2019

Lack of access to healthy food may contribute to health disparities in kidney disease

Processed and fast foods enriched with phosphorus additives may play a role in health disparities in chronic kidney disease, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN). Previously, genetics was considered the leading reason blacks are four times more likely to progress to end stage renal disease than whites and have much higher rates of cardiovascular disease and mortality in early chronic kidney disease (CKD).

Phosphorus, a mineral found naturally in foods such as milk, cheese, beans and peanut butter, is vital for the formation of bones and teeth, as well as energy production and the formation of cell membranes. Since the kidneys excrete excess phosphate, patients with CKD may develop increased blood levels of phosphate, or hyperphosphatemia. Manufacturers add phosphates to foods to give them a longer shelf life and make them more appealing.

Orlando M. Gutierrez, MD, MMSc, lead author; Myles Wolf, MD, MMSc, senior author; (University of Miami Medical School) and colleagues analyzed phosphate levels in the blood of patients participating in the Chronic Renal Insufficiency Cohort Study (CRIC), a prospective cohort study established by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) to examine risk factors for kidney disease progression and cardiovascular disease in patients with CKD.

“Many studies have demonstrated that an elevated level of phosphate in the blood is associated with adverse outcomes in patients with chronic kidney disease and that blacks have higher phosphate levels than whites but we did not understand why levels are higher in blacks,” said Wolf. “Our earlier work in the general population suggested that poverty was linked to a higher phosphate level, so we decided to delve deeper into that connection in the setting of chronic kidney disease.”

Among the 3,612 racially and ethnically diverse participants, those with the lowest incomes and those who were unemployed had higher phosphate concentrations in their blood than participants with higher income and rates of employment. Furthermore, there was no difference in phosphate levels by race when only blacks and whites in the lowest income group were compared. The investigators concluded that the known racial difference in phosphate levels is largely driven by differences in socioeconomic status.

Take-home message: “For low-income patients, access to healthy food choices is limited, so their diet tends to consist of processed and fast foods heavily enriched with highly-absorbable phosphorus additives,” said Gutierrez. “The amount of phosphorus additives in food is not always listed, so people unknowingly ingest more phosphorus than they probably should.”


Co-Authors: Cheryl Anderson, PhD, MS; Tamara Isakova, MD, MMSc; Julia Scialla, MD, Lavinia Negrea, MD; Amanda Hyre Anderson, PhD, MPH; Keith Bellovich, DO; Jing Chen, MD, MSc; Nancy Robinson, PhD; Akinlolu Ojo, MD, PhD; James Lash, MD; Harold I. Feldman, MD, MSCE.

Disclosures: Dr. Feldman received grant support from Amgen. All other authors reported no financial disclosures.

The article, entitled “Low Socioeconomic Status Associates with Higher Serum Phosphate Irrespective of Race” will appear online at http://jasn.asnjournals.org/ on September 16, 2010, doi 10.1681/ASN.2010020221.

The translated version of American Society of Nephrology material must also carry a disclaimer in English and in the language of the translation: The American Society of Nephrology takes no responsibility for the accuracy of the translation from the published English original and is not liable for any errors which may occur. No responsibility is assumed, and responsibility is hereby disclaimed, by the American Society of Nephrology for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of methods, products, instructions or ideas presented. Independent verification of diagnosis and drug dosages should be made. Discussions, views, and recommendations as to medical procedures, choice of drugs and drug dosages are the responsibility of the authors.

La versión traducida del material de la Sociedad Americana de Nefrología debe incluir también una aclaración en inglés y en el idioma de la traducción: La Sociedad Americana de Nefrología no asume ninguna responsabilidad por la exactitud de la traducción a partir del original publicado en inglés. Tampoco es responsable de errores que pudieran ocurrir. Por lo tanto, no se asume ninguna responsabilidad y la Sociedad Americana de Nefrología rechaza toda responsabilidad por cualquier lesión y/o daño a personas o propiedades vinculados a la seguridad de productos, negligencia, y otros, o por el uso u operación de métodos, productos, instrucciones o ideas que se presenten. Debe realizarse una verificación independiente del diagnóstico y de las dosis farmacológicas. La discusión, puntos de vista y recomendaciones relativas a los procedimientos médicos, elección de medicamentos y dosis de las medicinas son responsabilidad de sus autores.

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.

Founded in 1966, the American Society of Nephrology (ASN) is the world’s largest professional society devoted to the study of kidney disease. Comprised of 11,000 physicians and scientists, ASN continues to promote expert patient care, to advance medical research, and to educate the renal community. ASN also informs policymakers about issues of importance to kidney doctors and their patients. ASN funds research, and through its world-renowned meetings and first-class publications, disseminates information and educational tools that empower physicians.

Contact: Shari Leventhal
American Society of Nephrology

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