Added Sugars Linked to Kidney Stones

High consumption of added sugars may be a risk factor for developing kidney stones, a study finds.

A team of researchers analyzed epidemiological data on 28,303 adults collected between 2007 to 2018 within the U.S. National Health and Nutrition Examination Survey (NHANES). Participants self-reported if they had a history of kidney stones and the most recent consumption of food and drinks.

Each participant also received a healthy eating index score (HEI-2015) that shows if their diet includes enough beneficial components and whether they consume harmful foods in moderation.

At the beginning of the study, which appeared in the journal Frontiers in Nutrition, the participants with a higher added sugar intake had a higher current prevalence of kidney stones and lower HEI scores. On average, the participants consumed 272.1 calories from added sugars a day, which was equivalent to 13.2% of the total daily energy intake.

After adjusting for explanatory factors, the researchers found that the percentage of energy intake from added sugars was positively and consistently correlated with kidney stones.

For example, participants whose intake of added sugars was among the 25% highest in the population were 39% more likely to develop kidney stones over the course of the study.

Moreover, Native Americans or Asian participants, were at higher risk of developing kidney stones when consuming more than average amounts of added sugars compared to Mexican American, other Hispanic, non-Hispanic white, and non-Hispanic Black people.

The researchers still don’t know how consuming more added sugars may increase the risk of developing kidney stones. They also don’t rule out the possibility that unknown confounding factors might explain this association.

Lead author Shan Yin, a researcher at the Affiliated Hospital of North Sichuan Medical College, Nanchong, China, says that further studies are needed to explore the role of added sugar in various diseases.

"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?" Yin adds.

Added sugars, such as sucrose, dextrose, table sugar, and syrups, primarily come from sugary drinks, desserts, and sweet snacks. According to the Dietary Guidelines for Americans, individuals two years and older should keep their intake of added sugars to less than 10% of their total daily calories.

Kidney stones are solid, pebble-like deposits of minerals and salts that form inside the kidneys. They are caused by higher levels of calcium, oxalate, and phosphorus in the urine.

Men and those with a family history of kidney stones are more likely to develop the condition. Certain chronic illnesses, including urinary tract blockage, chronic bowel inflammation, and obesity, may also increase the risk.

Symptoms of kidney stones

• Sharp pains in the back, side, lower abdomen, or groin
• Pink, red, or brown blood in the urine
• A constant need to urinate
• Pain while urinating
• Inability to urinate or can only urinate a small amount
• Cloudy or bad-smelling urine

Pain may be accompanied by nausea and vomiting.

It remains unclear if high consumption of added sugar actually causes kidney stones. Nevertheless, limiting its intake may still benefit health, as the excess use of added sugar is linked to multiple conditions, including cardiovascular disease, diabetes, and high blood pressure.