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January 25, 2011––New research from Brigham and Women’s Hospital (BWH) finds that a Western dietary pattern, high in red and processed meats, saturated fats and sweets, is associated with increased odds of kidney function decline. This research is published online and in the February issue of the American Journal of Kidney Diseases, the official journal of the National Kidney Foundation.
“Traditional studies about diet and health focus on specific nutrients or foods, but dietary patterns may better reflect how people really eat,” said Julie Lin, MD, MPH, lead author on the paper and a physician in the Renal Division at BWH. “We found that a diet that is low in red meat, saturated fat, and sweets but high in whole grains and fruit and vegetables may be associated with slower loss of kidney function over time.”
In the first of its kind study to look at dietary patterns and change in kidney function over time, researchers evaluated the effect of three different dietary patterns, Western, Prudent and DASH–style*, on change in kidney function over 11 years in 3,121 female participants in the Nurses” Health Study. Kidney dysfunction was determined by two different measures that are both associated with cardiovascular disease and risk of death: estimated glomerular filtration rate (eGFR), which measures how well the kidney filters blood, and presence of microalbuminuria, a urinary protein that may be a marker of vascular disease and inflammation. While the women tended to have well functioning kidneys overall with very few who met criteria for having chronic kidney disease, the researchers found that the Western style diet was associated with increased levels of albuminuria and increased risk of rapid eGFR decline, while the DASH–style diet was inversely associated with eGFR decline. The association persisted after controlling for other health factors such as smoking, activity level, obesity and diabetes.
“The kidney is a highly vascular organ, so we were not surprised to see that the Western diet, which has been linked with an increased risk for cardiovascular disease, is also associated with kidney function decline over time,” Lin said. “Interestingly, this finding, along with other research, adds to growing evidence that albuminuria, which is widely considered to be an early reflection of vascular disease, may be influenced by diet.”
Researchers note that the study population is comprised mainly of middle–aged and older Caucasian women and that additional research is needed to examine the relationship between dietary patterns and progressive kidney dysfunction especially in non–whites and men.
“Protein in the urine, or albuminuria, is often an early sign of kidney disease and the National Kidney Foundation urges those at risk to get their kidney function tested so they can have the benefit of early intervention to prevent further kidney damage. This study suggests that diet plays a role in the decline of kidney function and that a heart–healthy diet can help keep kidneys healthy too,” says Kerry Willis, National Kidney Foundation Senior Vice President for Scientific Activities.
This research was funded by the National Institutes of Health.
For more information on kidney disease visit the National Kidney Foundation website at kidney.org.
*Western diet: Higher intake of red and processed meats, saturated fats, and sweets.
Prudent diet: Higher intake of fish and poultry as well as fruits, vegetables, and whole grains.
DASH–style diet (Dietary Approach to Stop Hypertension): Higher intake low–fat dairy, nuts, legumes (but lower intake of sweetened beverages) as well as fruits, vegetables, and whole grains.