Acid levels in the diet could have profound effects on kidney health

(Press-News.org) Contact information: Kurtis Pivert
kpivert@asn-online.org
202-699-0238
American Society of Nephrology
Acid levels in the diet could have profound effects on kidney health Atlanta, GA (November 9, 2013)—Three new studies suggest that controlling dietary acid intake could help improve kidney health. Results of these studies will be presented at ASN Kidney Week 2013 November 5-10 at the Georgia World Congress Center in Atlanta, GA.

A diet rich in wheat flour and animal protein produces an acidic environment in the body that worsens with age as kidney function declines. This acid load can be detrimental to a variety of tissues and processes. Research suggests that consuming more fruits and vegetables—which are highly alkaline—may help counteract these effects.

In a new study, a team led by Nimrit Goraya, MD (Texas A&M College of Medicine) investigated whether consuming fruits and vegetables can protect the kidney health of individuals with hypertensive nephropathy, a condition in which damage to the kidneys occurs due to high blood pressure. In this study, 23 hypertensive patients received extra dietary fruits and vegetables, 23 patients received an oral alkaline medication, and 25 patients received nothing. One year later, kidney injury progressed in patients who received no intervention, but kidney health was preserved in those receiving fruits and vegetables or oral alkaline medication.

In another study, Eiichiro Kanda, MD, PhD (Tokyo Kyosai Hospital) and his colleagues investigated the role of dietary acid levels in chronic kidney disease (CKD) progression. The retrospective study analyzed data from 249 CKD patients in Japan. High acid levels were linked with accelerated kidney function decline, and patients with elevated acid levels had an increased risk of CKD progression compared with patients with low acid levels. The findings suggest that monitoring and control of dietary acid levels are necessary for the prevention of CKD progression.

Another study led by Deidra Crews, MD, FASN (Johns Hopkins University School of Medicine) looked to see whether the effect of dietary acid on risk of kidney failure differed by race in a group of 159 non-Hispanic black and 760 non-Hispanic white CKD patients who had an annual household income below 300% of the federal poverty guideline. Participants were taking part in the 1999-2004 National Health and Nutrition Examination Survey. Overall, 12.4% of participants (38.3% whites and 61.7% blacks) developed kidney failure during an average of 6.4 years of follow up. Blacks had higher acid levels than whites. They also had a 3-fold higher risk of developing kidney failure compared with whites after adjusting for factors such as age, sex, and caloric intake. Increased acid levels were more strongly associated with kidney failure among blacks than among whites. The findings indicate that among CKD patients with low socioeconomic status, the detrimental effect of high dietary acid levels on progression to kidney failure appears to be greater for blacks than for whites.

### Highlights In patients with hypertensive nephropathy, kidney health was preserved in those consuming extra fruits and vegetables, which are highly alkaline. In patients with chronic kidney disease, those with high dietary acid levels experienced accelerated kidney function decline. In chronic kidney disease patients with low socioeconomic status, the detrimental effect of high dietary acid levels on progression to kidney failure was greater for blacks than for whites.

Studies:

"Fruits and Vegetables or Oral NaHCO3 Prevent Progression of Kidney Injury in Stage 1 CKD Due to Hypertensive Nephropathy." (Abstract FR-PO816)

"Dietary Acid Load Is Associated with Chronic Kidney Disease Progression in Elderly Patients." (Abstract TH-PO243) Disclosures: Masumi Ai receives research funding from MSD, Co., and Kyowa-Kirin, Co. Masayuki Yoshida receives research funding and honoraria from Astra Zeneca, Novartis, Pfizer, MSD, and Bayer.

"Race, Dietary Acid Load and Risk of ESRD among Low Income Americans with CKD." (Abstract SA-OR050) Disclosures: Deidra C. Crews is a consultant for The Boston Consulting Group and receives honoraria from the National Institute on Aging and National Institutes of Health. Hal Morgenstern is a consultant for the Arbor Research for Collaborative Health. Rajiv Saran receives research funding from the Renal Research Institute, Forest Research Institute, and Arbor Research Collaborative for Health; and honoraria from Otsuka. Neil R. Powe receives honoraria from ABIM, ASN, Robert Wood Johnson Foundation, Vanderbilt University, Commonwealth Fund, Informed Medical Decision Making Foundation. The authors report funding from the Department of Defense.

ASN Kidney Week 2013, the largest nephrology meeting of its kind, will provide a forum for 14,000 professionals to discuss the latest findings in renal research and engage in educational sessions related to advances in the care of patients with kidney and related disorders. Kidney Week 2013 will take place November 5 – 10, 2013 in Atlanta, GA.

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Founded in 1966, and with more than 14,000 members, the American Society of Nephrology (ASN) leads the fight against kidney disease by educating health professionals, sharing new knowledge, advancing research, and advocating the highest quality care for patients.