People who consumed the most ultra-processed foods are at higher risk for chronic kidney disease, according to a new study published in the American Journal of Kidney Diseases.
Ultra-processed foods are defined as containing minimal to no whole foods — foods in their natural form — and are often processed with chemicals like dyes, flavorings, and preservatives. They are also often high in calories, salt, sugar, and saturated fat but low in beneficial nutrients like vitamins, minerals, and phytochemicals (healthy plant compounds). Studies have shown that ultra-processed foods make up most of the calories that people consume in some countries, including the United States — and that these foods may pose unique health dangers. Ultra-processed foods are linked to a higher risk of developing type 2 diabetes, a higher risk of dying in people with cardiovascular disease, a higher body weight as an adult when consumed during childhood, and a higher risk for high blood pressure in Black adults.
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For the latest study, researchers looked at data for 14,679 middle-aged adults who didn’t have chronic kidney disease at the beginning of the study. Participants were followed for a median of 24 years after filling out a detailed food frequency questionnaire at two different visits. During the follow-up period, the researchers recorded new cases of chronic kidney disease, as defined by an eGFR (estimated glomerular filtration rate) below 60, combined with at least a 25% overall decline in this number.
Ultra-processed food consumption linked to chronic kidney disease
During the follow-up period, the incidence of chronic kidney disease in the top quarter of participants based on ultra-processed food consumption was 16.5 per 1,000 person-years, compared with 14.7 in the bottom quarter of ultra-processed food consumption. After adjusting for numerous factors linked to the risk of developing kidney disease — other than dietary factors — the researchers found that participants in the top quarter based on ultra-processed food consumption were 24% more likely to develop chronic kidney disease, compared with the bottom quarter.
What’s more, the relationship between ultra-processed food consumption and developing chronic kidney disease was close to linear across all levels of consumption — meaning that the risk went up in a way that was proportionate to how much of these foods people ate. This linear relationship is strong evidence that the higher kidney disease risk was actually caused by a higher intake of ultra-processed foods, although this isn’t something that an observational study can prove.
The researchers concluded that a higher intake of ultra-processed foods is linked to a higher long-term risk for kidney disease in the general population. It stands to reason, of course, that certain groups at higher risk for chronic kidney disease — especially people with diabetes — might benefit even more than most people from avoiding ultra-processed foods when it comes to kidney health.
Want to learn more about keeping your kidneys healthy with diabetes? Read “Managing Diabetic Kidney Disease,” “How to Keep Your Kidneys Healthy,” “Protecting Your Kidneys,” and “Kidney Disease: Your Seven-Step Plan for Prevention.”