Dietary factors influence the risk of kidney stone formations; however, no prospective information is available in younger women. Curhan et al prospectively examined, during an 8-year period, the association between dietary factors and the risk of incident symptomatic kidney stones among 96 245 female participants in the Nurses' Health Study II who were aged 27 to 44 years and who had no history of kidney stones. The authors documented 1223 incident symptomatic kidney stones during 685 973 person-years of follow-up. After relevant risk factors were adjusted for, dietary factors that were independently associated with a reduced risk of kidney stones were dietary calcium, phytate, and fluid intake. Sucrose intake was associated with an increased risk. Sodium, potassium, and magnesium intake were not independently associated with risk. These findings indicate that a higher intake of dietary calcium decreases the risk of kidney stone formation in younger women and should not be routinely restricted. The authors also suggest that dietary phytate may be a new, important, and safe addition to options for stone prevention.