Sugar-Heavy Diet Linked to Development of Kidney Stones

A diet high in added sugars may predispose people to developing kidney stones, a nationally representative study suggested.

In an analysis of over 28,000 U.S. adults, those who consumed the most energy from added sugars had 39% higher odds of developing kidney stones compared with those who consumed the least amount of added sugars (OR 1.39, 95% CI 1.17-1.65, P<0.001 for trend), found Shan Yin, MD, of the Affiliated Hospital of North Sichuan Medical College in Nanchong, China, and colleagues.

Those falling into the highest quartile for added sugar intake consumed on average 542.11 kcal a day versus 58.25 kcal among those in the lowest quartile, the group noted in Frontiers in Nutrition.

Those who consumed 25% or more of their daily calories from added sugars had an 88% higher odds of kidney stones compared with those who kept their added sugar intake to less than 5% of their daily calories (OR 1.88, 95% CI 1.52-2.32, P<0.001 for trend).

"Ours is the first study to report an association between added sugar consumption and kidney stones," Yin said in a statement. "It suggests that limiting added sugar intake may help to prevent the formation of kidney stones."

David S. Goldfarb, MD, co-director of the Kidney Stone Prevention Program at NYU Langone Health in New York City, noted that "there has long been evidence that sugar increases the amount of calcium in urine, and there have been multiple reasons why avoidance of sugar would be part of a diet encouraging kidney stone prevention."

"This study serves as a large dataset with good credibility and includes a relatively representative group of people in the United States," added Goldfarb, who was not part of the study. "From this point of view, the study is important because it documents what we have been telling patients -- to avoid this kind of added sugar."

"Added sugars can also cause increased weight gain, which is associated with high blood pressure, insulin resistance, metabolic syndrome, and diabetes -- all of which are considered risk factors for increased rates of kidney stones," he said. "In general, dietary changes that support kidney health are also associated with decreased rates of kidney stones."

This study used data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2018, and included 28,303 adults (48% men) with an average age of 48.

Models were fully adjusted for gender, age, race, poverty income ratio, body mass index, education, marital status, smoking, alcohol intake, total energy intake, Healthy Eating Index (HEI)-2015 score, physical activity, gout, diabetes, hypertension, stroke, cardiovascular disease, cancer, and year cycle.

Higher consumers of added sugar tended to have lower education levels and lower HEI scores.

The link between consumption of added sugars and risk of developing kidney stones also appeared to vary by race. When comparing those who consumed at least 25% of their daily caloric intake through added sugars with those who consumed less than 5%, risk for kidney stones was highest for those in the "other races" category (OR 3.53, 95% CI 1.69-7.38), followed by Hispanic adults (OR 2.16, 95% CI 1.26-3.7) and non-Hispanic white adults (OR 1.90, 95% CI 1.47-2.45). This association was smaller for those who were Mexican American (OR 1.29, 95% 0.77-2.15) and non-Hispanic Black (OR 1.09, 95% CI 0.71-1.66).

"Further studies are needed to explore the association between added sugar and various diseases or pathological conditions in detail," Yin said in the statement. "For example, what types of kidney stones are most associated with added sugar intake? How much should we reduce our consumption of added sugars to lower the risk of kidney stone formation?"

"Nevertheless, our findings already offer valuable insights for decision-makers," he added.

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