People who frequently consume artificially sweetened diet sodas appear to have greater risks of end-stage renal disease (ESRD), according to a new study.
Within a general population, ESRD risk was greater by 8%, 33%, and 83%, for those who consumed 1–4, 5–7, and more than 7 (8-ounce) glasses of diet soft drinks each week, respectively, compared with those who consumed less. The investigators found weaker associations between diet soda intake and earlier stages of kidney disease.
“Given the high prevalence of diet soda consumption in the United States, this finding could have a significant public health effect,” Casey M. Rebholz, PhD, MS, MPH, of Johns Hopkins Bloomberg School of Public Health in Baltimore, and colleagues concluded in the Clinical Journal of the American Society of Nephrology.
For their analysis of the Atherosclerosis Risk in Communities study, Dr Rebholz and colleagues prospectively analyzed diet soda consumption, assessed by food frequency questionnaires for 15,368 black and white participants (aged 45 to 64) during 1987 to 1989 and 1993 to 1995. During 23 years of follow up through 2012, ESRD developed in 357 participants.
To minimize confounding, the investigators adjusted results for demographic and lifestyle features such as age, sex, race, education, smoking, physical activity, and daily calories. They also accounted for established ESRD risk factors, including body mass index (BMI), diabetes, systolic blood pressure, serum uric acid, and estimated glomerular filtration rate (eGFR). Although ESRD risks were similar by BMI category, the only significant association between diet soda intake and ESRD was found for individuals who were overweight or obese at baseline. Among participants, 12% had diabetes and 35% had hypertension. Baseline eGFR was 102.5 mL/min/1.73 m2, on average.
Since diet can influence kidney disease progression, the investigators further adjusted for dietary acid load – the balance of acid-inducing foods such as meats, eggs, and cheese and base-inducing foods including fruits and vegetables—overall diet quality, sodium intake, fructose consumption, and sugar-sweetened beverages. In analyses, sugary drinks were not significantly associated with ESRD.
Dietary phosphorus was higher among frequent consumers of diet soft drinks. Both sugar-sweetened and diet sodas contain phosphorus additives, which can increase serum phosphorus and fibroblast growth factor-23. A previous analysis of the same study population found double the risk of ESRD among those with the highest versus lowest levels of fibroblast growth factor-23, according to findings published in the Journal of the American Society of Nephrology (2015;26:192-200). Phosphorus additives in diet soda can also increase dietary acid load and thereby contribute to ESRD.
When the investigators adjusted results for dietary phosphorus, they found no relationship. However, food frequency questionnaires may underestimate the intake of micronutrients such as phosphorus. Several other mechanisms linking diet soft drinks and ESRD are likewise plausible, such as impaired glucose metabolism, although the investigators adjusted for diabetes.
1. 1. Rebholz CM, Grams ME, Steffen LM, et al. Diet Soda Consumption and Risk of Incident End Stage Renal Disease. Clin J Am Soc Nephrol 12: ccc–ccc, 2017. doi: 10.2215/CJN.03390316.