Chronic kidney disease (CKD) affects an estimated 13% of the U.S. population, about 37 million people. Dietary guidelines generally focus on what nutrients, such as the minerals phosphorus, potassium, and sodium, should be limited or at least strictly regulated. Less emphasis has been placed on what foods might have a protective effect and help prevent either the development or the progression of the disease. 

While the general benefits of eating fresh, healthy produce has long been known, a University of Virginia School of Medicine study research now shows that increasing our fruit and vegetable intake may also help prevent—and treat—CKD.*  

What the researchers did

For the study, published in the Journal of Renal Nutrition, the research team analyzed 24-hour dietary recall data from the National Health and Nutrition Examination Survey (NHANES) across three groups from 1988-1994, 2003-2010, and 2011-2018. 

The types of fruits and vegetables evaluated included: citrus fruits and juices, dried fruits and berries and other fruits and fruit juices, potatoes and other starchy vegetables, cabbage, dark green leafy vegetables, deep-yellow vegetables, tomatoes, and other vegetables. 

The foods were categorized as:

• Unprocessed, or obtained directly from plants
• Minimally processed, which might include cleaning, drying, freezing, or fermenting, 
• Processed, but still recognizable as version of the natural food, and
• Ultra-processed, extracted from foods, but drastically changed, or synthesized in laboratories

Finally, the research team identified patterns of fruit and vegetable intake among people with and without CKD, and compared them. 

What they found

The researchers discovered that participants with CKD:

• Were more likely to show patterns of low fruit and vegetable consumption compared to participants without CKD
• Had higher dietary potassium densities than non-CKD participants, and 
• Consumed fewer overall calories than those without CKD.

“Consuming more fruits and vegetables is strongly linked to health in many different diseases,” said UVA Health kidney specialist Dr. Julia J. Scialla. “We worry about overall health effects when we see patients with chronic kidney disease consuming low levels of fruits and vegetables.”

What it means

The study authors point out that their findings could lead to more than one conclusion, however. For instance, they may suggest that: 

• Low intake of fruits and vegetables is a risk factor for the development of CKD, or 
• People with CKD eat fewer fruits and vegetables in order to reduce their potassium intake, per the standard cautions. 

Despite this common guidance, Scialla says that not enough is known about the nutritional benefits of potassium, and that “it is important not to scare away patients from fruits and vegetables” and the health benefits they confer from their many vitamins, minerals, fiber, and anti-inflammatory phytochemicals.

Further studies, she says, with a particular focus on evaluating fruit and vegetable intake patterns in cases of both new onset CKD and CKD progression, need to be done to gain more clarity, and to better understand both benefits and risk factors. 

With CKD on the rise, determining how much of a role diet plays when considering other factors will be key to delaying and preventing CKD progression. In addition, the researchers believe more work needs to be done on figuring out how to get Americans to eat more fruits and vegetables. 

Through this and similar studies, adds Shirin Pourafshar, nutritionist, dietician, and study co-author, they hope to “encourage both healthy individuals and patients with chronic kidney disease to reconsider their intake of fruits and vegetables by incorporating greater varieties and amounts of unprocessed or minimally processed fruits and vegetables into their everyday diets.” 

*Swensen, E. (2022, July 26). Eating more fruits and veggies could benefit your kidneys. Medical Xpress. https://medicalxpress.com/news/2022-07-fruits-veggies-benefit-kidneys.html