Purdue Nutrition Science researcher warns against processed foods for chronic kidney disease patients

Annabel Biruete

Written by: Tim Brouk, tbrouk@purdue.edu

Ham is under the microscope — and the carving knife.

The processed meat was deemed a Group 1 carcinogen by the World Health Organization and then a decade later, The BMJ journal warned of food additive preservatives like those found in ham to be associated with cancer incidence.

Such processed foods can negatively impact the health of chronic kidney disease (CKD) patients too. Annabel Biruete, assistant professor at Purdue University Department of Nutrition Science, recently co-chaired and was the lead author on the latest guidance from the American Society of Nephrology on nutrition for CKD patients. The guidance focuses on potassium and phosphorus additives, which are used by food manufacturers to improve shelf life, flavor, color and texture of their products. While troublesome for a healthy person in large amounts, these additives can be detrimental for CKD patients in multiple ways.

“Foods with these additives are usually not recommended for people with kidney disease because they are easy to absorb,” Biruete explained. “As CKD advances to kidney failure, it is harder to maintain blood phosphorus and potassium in normal concentrations, which can lead to higher cardiovascular mortality and bone problems.”

Instead of focusing on the processed foods they can’t eat, Biruete and her colleagues want CKD patients to focus on a healthy diet emphasizing balance, moderation and variety — and to limit the intake of foods with these additives.  

Subtracting additives

Phosphorus additives offer no known health benefit and are strongly linked to bone disease, heart problems and hormone imbalances in people with kidney disease. Biruete’s work shows that even when blood phosphorus levels appear normal, excess intake from additives can still cause harm over time.

Potassium additives can offer some cardiovascular benefit to a healthy adult and even those with CKD in early stages without risk of having high blood potassium, but they can be harmful to patients with advanced CKD. Biruete and her colleagues dissected potassium chloride, potassium citrate, potassium lactate and potassium phosphate as high-risk potassium food additives. Such additives are found in products like low-sodium canned soup. These potassium additives are not recommended for CKD patients who are at high risk of high blood potassium because their bodies have lost the ability to excrete excess potassium. Too much potassium could lead to irregular heartbeats, heart attack or even sudden cardiac death, along with symptoms such as muscle weakness, numbness and nausea. But instead of lamenting the loss of that can of Progresso Roasted Chicken Noodle soup, patients should shift their diets to healthier, more natural foods, according to Biruete.

“Healthy dietary patterns are those that contain more fruits and vegetables, whole grains, legumes or plant-based proteins, nuts, and seeds. It doesn’t mean that they are vegan. They can also have moderate amounts of animal-based products as well,” Biruete said. “Such dietary patterns have been linked to lower risk of diabetes and hypertension — the leading causes of CKD — and also lower risks of kidney disease.”

Why kidneys?

Biruete’s journey to leading studies and nutrition guidelines for CKD patients began during her nutrition undergraduate studies at Escuela de Dietética y Nutrición in Mexico City. Her senior year was spent working in a hospital, focusing on nutrition support, where she was involved in a few small research projects. One project saw her working with patients starting peritoneal dialysis, which uses the patient’s abdominal lining or peritoneum as a filter to clean their blood.

For graduate school at the University of Illinois, she joined a lab that worked with patients with CKD undergoing hemodialysis.

“We did a variety of research projects on lifestyle interventions. For example, protein supplementation and exercise during dialysis. During my PhD is where my interest in the role of dietary fiber in kidney disease started. I saw the important impact of nutrition in a variety of outcomes in CKD, furthering my commitment to this area of research,” recalled Biruete, also noting her grandfather’s lifelong struggles with kidney disease still inspire her work.

Up next

Biruete’s lab has multiple ongoing projects for 2026. One study funded by the American Society of Nephrology will look at how dietary fiber supplements impact people with CKD. This study is the next step following her studies in rat models of kidney disease, which showed promising results in slowing the progression of mineral and bone disorders. Another study will look at cardiovascular, bone and kidney function during menopause and how a dietary intervention affects women during this stage. The work will be funded by the Purdue Women’s Global Health Institute via a pilot grant.

“We’re trying to see if a dietary intervention can prevent or slow or give us some signal that it can improve bone, cardiovascular and kidney health. So, this pilot grant is going to help us get pilot data for a bigger grant application,” Biruete said.

Biruete noted this arm of research is inspired by the American Heart Association’s concept of “cardiovascular-kidney-metabolic health”  — an “integrated whole-person care for cardiovascular, kidney and metabolic conditions” through diet.

“We’re expanding a lot of our research to try to maximize that,” Biruete said. “Hopefully, in the next five to 10 years, we will be going from supplements to food-based interventions, and all the way to whole dietary patterns and their impact on cardiovascular-kidney-metabolic health.”