May 2, 2023 – Your kidneys may be hailing the “COVID-19 diet.”

Some patients prone to kidney stones lowered the amount of sodium and calcium they consumed in 2020 as they switched to home cooking during the pandemic lockdowns, and the reductions have persisted even as restaurants have reopened. 

Researchers from the Department of Urology at Stony Brook University Hospital in Stony Brook, NY, reported the findings recently at the 2023 meeting of the American Urology Association.

“Subjectively, we noticed our friends, families and our patients reporting that they starting cooking more at home and started eating less out at restaurants; one patient called it the ‘COVID-19 diet,’ ” said David Schulsinger, MD, an associate professor of urology at Stony Brook and the senior author of the study.

Restaurants were closed in New York state starting in March 2020. 

Schulsinger said reducing the intake of sodium can lower the risk for hypernatriuria or hypercalciuria (too much sodium or calcium in the urine, respectively), thus lowering the risk for kidney stones, because home cooking allows patients greater control over how they season their food.

In the study, 93 kidney stone patients (54 men and 39 women; average age 60.1) had 24-hour urine studies at three points in time: before March 16, 2020; over the following 10-month period; and a “post-COVID-19” stage between Jan. 1, 2021, and Oct. 31, 2022.

Levels of urinary sodium decreased by about 10% during the pandemic and settled into about 17% lower during the post-COVID time period. Urinary calcium also fell by about 10% during the pandemic, and levels remained improved, about 13% lower, in the post-COVID period, according to the researchers.