Study authors Mary L'Abbe of the University of Toronto and graduate student Mary Scourboutakos analyzed nutrition data from the websites of 20 major sit-down and 65 fast-food restaurants in Canada in 2010 and early 2011.
L'Abbe and Scourboutakos used U.S. sodium recommendations because Canada has not established targets or implemented a salt-reduction strategy for restaurants, the Canadian Broadcasting Corp. reported.
"Because of the prevalence of eating out, as well as the high rates of hypertension and cardiovascular disease, addressing the exceedingly high sodium levels in restaurant foods is essential in order to decrease the burden of chronic disease," the researchers wrote in the study.
The study, published in the Canadian Journal of Public Health, found, on average, individual sit-down restaurant menu items contained 1,455 milligrams of sodium per serving, or 97 percent of the recommended adequate intake level of 1,500 mg/day.
In addition, 40 percent of all sit-down restaurant items exceeded the adequate intake level for sodium and more than 22 percent of sit-down restaurant stir fry entrees, sandwiches/wraps, ribs and pasta entrees with meat/seafood exceeded the daily tolerable upper intake level for sodium of 2,300 mg.