High levels of fructose intake are independently associated with an increased risk of kidney stones, according to researchers.
The finding, by Eric N. Taylor, MD, and Gary C. Curhan, MD, of the Channing Laboratory in Boston, is based on data from 93,730 women in the Nurses’ Health Study I (NHS I), 101,824 women in the Nurses’ Health Study II (NHS II), and 45,984 men in the Health Professionals Follow-up Study (HPFS). Investigators used food frequency questionnaires to assess free fructose and sucrose intake every four years. During a combined 48 years of follow-up, researchers documented 4,902 new symptomatic kidney stones.
Compared with lowest quintile of total fructose intake, the highest quintile was associated with a 37% in-creased risk of a new kidney stone in the older women, a 35% increased risk in the younger women, and a 27% increased in the men, after adjusting for potential confounders, the researchers reported in Kidney International (2008;73:207-212).
NHS I enrolled women aged 30-55 years in 1976. NHS II enrolled women aged 25-42 years in 1989. The HPFS enrolled male health professionals aged 40-75 years in 1986.
“Clinicians caring for patients with stone disease should make sure that individuals who decrease their intake of protein or fat are aware that they should not subsequently increase their consumption of fructose-rich foods,” the authors wrote.
Drs. Taylor and Curhan observed that fructose consumption has increased substantially in the past few decades. “This intake,” they noted, “may increase the urinary excretion of calcium, oxalate, uric acid, and other factors associated with kidney stone risk.”