A new study reveals “inflammatory” diets can hurt people with kidney disease.

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Diets that are high in processed foods may hurt people with kidney disease. Getty Images

Diet is an important part of managing many health conditions, and new research is shining a light on how essential it can be for healthy kidneys.

Researchers at the American Society of Nephrology last month demonstrated a link between pro-inflammatory diets to a higher risk of developing kidney failure, identified as end stage renal disease (ESRD) in people with chronic kidney disease (CKD).

“The implication of the study would be that based on our findings, we suggest that anti-inflammatory diets be tested whether they can lead to lower rates of [end stage renal disease] because our findings show a high risk of ESRD with a pro-inflammatory diet,” Tanushree Banerjee, PhD, the presenter of the research and a research specialist in the Department of Medicine at University of California San Francisco, told Healthline.

What the study found

Banerjee and her team looked at data from the National Health and Nutrition Examination Survey and linked it with the U.S. Renal Data System to see how pro-inflammatory diets affected the progression of CKD to kidney failure.

They analyzed a group of 1,084 adults ages 20 and older, all of whom had CKD, and found that 120 participants, about 11 percent, developed ESRD over the course of 14 years of follow-up.

The researchers used a tool called the Adapted Dietary Inflammatory Index. Developed in 2009, the index implements a scoring system to categorize dietary components according to whether they are pro- or anti-inflammatory.

The risk of developing ESRD was higher if individuals consumed more pro-inflammatory foods. The higher the score of their diet on the index, the greater the risk.

“Many common diseases are thought to be linked to chronic inflammation,” said Dr. Anjay Rastogi, professor and clinical chief of nephrology at the David Geffen School of Medicine at University of California Los Angeles, who isn’t affiliated with the study.

“These include but are not limited to cancer, diabetes, and cardiovascular disease. Kidney disease is also linked to inflammation. Anything that induces, potentiates, or worsens inflammation can potentially lead to worsening of kidney disease.”

Rastogi pointed that “diet has a very important role in slowing down the CKD and optimizing the ESRD care.”

Roughly 30 million people in the United States are affected by chronic kidney disease, according to the Centers for Disease Control and Prevention (CDC). However, only about 48 percent of individuals with severe CKD and 4 percent of those with minor symptoms are even aware they have it.

CKD is characterized by low-grade inflammation and tends to get worse over time, leading to kidney failure. When a person’s kidneys stop working completely, they must either undergo dialysis treatments or receive a kidney transplant.

While there are numerous variables — including high blood pressure, diabetes, and drug use — that can affect progression of CKD, increased inflammation has also previously been associated with a faster progression of the condition.

Individuals with CKD are typically cautioned about their intake of certain dietary components, including fluids, minerals such as phosphorus and potassium, and salt, to try to protect their kidneys.

Now Banerjee’s research urges for even more diligence toward diet, to prevent progression of the disease.

“If dietary modifications are introduced in an individual’s lifetime, it can kind of eliminate to a great extent the risk of progressing to ESRD,” she said.

In the next phase of research, Banerjee said she hopes to specifically look at the potential benefits of anti-inflammatory diets and if they will actually lower rates of kidney failure in people with CKD.

Which foods cause inflammation?

Foods that cause inflammation in the body are numerous and often found in popular dishes in the United States. Pro-inflammatory foods include refined carbohydrates (unlike high-fiber, whole-grain carbs), sugar and high-fructose corn syrup, red meat, soda and other carbonated beverages, and fried foods.

Even some vegetables, such as those in the nightshade family — including tomatoes, eggplants, and peppers — can cause inflammatory reactions.

“Let’s define what an inflammatory diet actually is. It’s one that contains not enough fruits and vegetables, not enough color, not enough whole grains and legumes, and way too much processed foods,” Kristin Kirkpatrick, MS, RD, LD, a licensed, registered dietitian who is wellness manager at the Cleveland Clinic Wellness Institute, told Healthline.

She recommends a few general steps to cut down on pro-inflammatory food items. But individuals, especially those with CKD, should speak with their doctor or dietitian before making major changes to their diet.

“The key to following an anti-inflammatory diet includes getting more color in your diet (through an increased consumption of fruits and vegetables), more healthy fats (like omega-3 fatty acids found in wild salmon and trout as well as walnuts) and more beans and intact whole grains,” said Kirkpatrick.

“In conjunction with this, consider limiting sugar in the diet to no more than 25 g added sugar or less and avoid fried foods, processed foods, and refined flours,” she said.