Key takeaways:

• Risk for developing CKD was greatest among individuals who ate the most ultraprocessed animal-based products.
• The health benefits of plant foods may be diminished if they are ultraprocessed.

Ultraprocessed animal- and plant-based foods were associated with greater risks for developing chronic kidney disease among older adults, according to data published in the Clinical Journal of the American Society of Nephrology.

Previous studies have linked plant-based choices to preserved kidney function and a lower risk for developing CKD, according to Hyunju Kim, PhD, MPH, assistant professor in the department of epidemiology at University of Washington, Seattle, and colleagues. However, highly processed plant-based products may not provide the same health benefits as minimally processed plant foods, Kim said.

Data derived from Hill CM, et al. Clin J Am Soc Nephrol. 2026;doi:10.2215/CJN.0000001207.

“Certain plant products, such as sugar-sweetened beverages, can be highly processed, and the health impacts of plant-sourced ultraprocessed foods remain unknown,” Kim told Healio. “To address these gaps, we assessed whether individuals with greater intake of total, plant- or animal-sourced ultraprocessed foods have a greater risk of incident CKD.”

Using data from the Cardiovascular Health Study, the researchers analyzed the association between eating more ultraprocessed foods and CKD development (defined as eGFR < 60 mL/min/1.73 m²) among 2,661 older adults (mean age, 71 years; 61% women; 95% white).

Food servings per day were measured twice (at baseline and 6 years) with food frequency questionnaires and classified by the degree of processing using the Nova system of food classification.

“For each exposure, participants in the top third of intake were assigned to the highest tertile and those in the bottom third were assigned to the lowest tertile,” Kim said. “Compared to those in the lowest tertiles, those in the highest tertiles generally had diets higher in total fat but lower in carbohydrate, protein, cholesterol, dietary fiber, vitamins A and D and many micronutrients.”

Results showed that after a median follow-up of 6.8 years, risks for developing CKD were significantly higher among individuals who consumed the most ultraprocessed foods overall (HR = 1.26; 95% CI, 1.08-1.47) and the most ultraprocessed animal-based foods (HR = 1.37; 95% CI, 1.17-1.6) vs. individuals in the lowest tertile.

Individuals who consumed more minimally processed foods had a lower risk for developing CKD vs. individuals in the lowest tertile (HR = 0.8; 95% CI, 0.69-0.95).

In addition, each standard deviation increase in ultraprocessed plant food consumption was associated with a greater risk for developing CKD (HR = 1.07; 95% CI, 1.01-1.13).

Furthermore, the researchers found risks for developing CKD slightly increased when replacing three servings of minimally processed foods with three servings of ultraprocessed foods (HR = 1.02; 95% CI, 1.001-1.03) or replacing three servings of minimally processed plant foods with ultraprocessed plant foods (HR = 1.02; 95% CI, 1.002-1.05).

Overall, the findings show that eating more ultraprocessed foods may increase the risk for developing CKD for older adults, particularly when consuming animal-based food products.

“Our data suggest that health benefits associated with plant food intake may be dampened by ultraprocessing,” Kim said. “However, we believe that additional work is needed in younger populations. It would also be interesting to extend this work to those with CKD and assess whether plant- or animal-sourced ultraprocessed food is associated with CKD progression.”

Clinicians can help patients distinguish between ultraprocessed and minimally processed foods by encouraging them to look at the ingredients list on a product, Kim said.

“Ultraprocessed foods are defined by the presence of industrial substances, which include additives such as sweeteners, emulsifiers, colors, flavors and preservatives,” Kim said. “If there are ingredients that patients don’t use in their own kitchen, that product is highly likely to be an ultraprocessed food.”

For more information:

Hyunju Kim, PhD, MPH, can be reached at hyunjuk1@uw.edu.