Adding Salt to Food Increases CKD Risk by 4–11%

Last week, a public health investigation published in JAMA Network Open analyzing the correlation between salt consumption and chronic kidney disease (CKD) risk identified a positive correlation between adding salt to food and the probability of developing CKD.

The prospective, population-based cohort study used data from the UK biobank, evaluating participants between 37 and 73 who did not have CKD at the start of the study. Participants were characterized based on their salt intake in the following categories: never or rarely, sometimes, usually, and always adding salt to their food.

Additionally, cases of CKD were identified based on diagnostic codes.

After gathering the data on the participants, the researchers calculated hazard ratios for CKD incidence, adjusting for multiple factors, including age, race, sex, estimated glomerular filtration rate (eGFR), Townsend Deprivation Index, body mass index (BMI), smoking status, alcohol consumption, frequency of physical activity, cholesterol levels, diabetes status, cardiovascular disease, hypertension, and other conditions.

According to the data, increased salt intake is associated with lower eGFRs. Estimated glomerular filtration rates are often used to indicate CKD risk, with lower rates associated with increased CKD risk.

Using data from over 450,000 participants, researchers revealed that sometimes adding salt to food increased the risk of CKD by 4% compared to individuals who reported never or rarely adding salt to their food.

Beyond that, those who reported usually adding salt to food were 7% more likely to develop CKD than those who rarely or never added salt. Finally, those who always added salt to their food had an 11% greater probability of developing CKD.

“To our knowledge, this is the first study indicating that higher self-reported frequency of adding salt to foods is associated with a higher CKD risk in the general population. The strengths of this study include the prospective design, large sample size, extensive information of covariates, the unique methods for investigating long-term habitual sodium intake, and the consistent results in sensitivity analyses,” concluded researchers in the study.

The data echoes healthcare organizations' recommendations suggesting a lower-salt diet for improved kidney health. For example, the American Kidney Fund recommends choosing and preparing food with less salt. Additionally, the National Kidney Fund also suggests managing sodium intake.