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Diet for lowering blood pressure also reduces risk of kidney disease

Benefit seen with diet high in whole grains, nuts, legumes, fruits and vegetables

Ingrid Torjesen

Wednesday, 10 August 2016

People who ate a diet high in nuts and legumes, low-fat dairy, whole grains, fruits, and vegetables and low in red and processed meat, sugar-sweetened beverages and sodium had a significantly lower risk of developing chronic kidney disease over the course of more than two decades, a study* published in the American Journal of Kidney Diseases shows.

The diet, known as DASH for Dietary Approaches to Stop Hypertension, was designed to help reduce blood pressure, but research has already shown it to be effective in preventing a series of other chronic illnesses, including cardiovascular disease, and now kidney disease can be added to that list.

The researchers examined records from the Atherosclerosis Risk in Communities (ARIC) Study, which in 1987 began following a group of 15,792 middle-aged adults from communities in Maryland, North Carolina, Minnesota and Mississippi for more than 20 years. At two early visits, participants filled out a 66-item food frequency questionnaire, which asked how often, on average, they consumed each food item in what portion size over the previous year.

The participants were not instructed what to eat, but rather their adherence to a DASH-style diet was later categorised into a score based on low intake of red and processed meat, sweetened beverages and sodium; and high intake of fruits, vegetables, whole grains, nuts and legumes, and low-fat dairy.

The researchers then determined whether participants developed kidney disease through results of blood tests assessing kidney function, and whether there had been hospitalisation or treatment kidney disease, or death from kidney disease.

The results showed that participants with the lowest DASH diet scores (those who ate few foods such as fruits, vegetables and nuts, and consumed more red meat and sodium) were 16% more likely to develop kidney disease than those with the highest DASH scores (those who ate more of the healthier foods and less of the unhealthy items).

Participants who had the highest intake of red and processed meats had a 22% higher risk of developing chronic kidney disease than those with the lowest intake of those foods, and those with the highest intake of nuts and legumes were at 9% lower risk of developing kidney disease than those with the lowest intake.

Lead researcher Casey Rebholz, assistant professor in the Department of Epidemiology at the John Hopkins Bloomberg School of Public Health, said: "In addition to offering other health benefits, consuming a DASH-style diet could help reduce the risk of developing kidney disease. The great thing about this finding is that we aren't talking about a fad diet. This is something that many physicians already recommend to help prevent chronic disease."

She suggested that DASH-style diets might stave off kidney disease because they reduce blood pressure, and hypertension has been linked to kidney disease. Alternatively the finding might be related to the overall acidity of the foods as high dietary acid has been linked to kidney disease; high acid foods include meats and cheeses, while low acid foods include fruits and vegetables.

* Rebholz CM, et al. DASH (Dietary Approaches to Stop Hypertension) Diet and Risk of Subsequent Kidney Disease. American Journal of Kidney Diseases. DOI: 10.1053/j.ajkd.2016.05.019

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