NEW YORK — New York City’s pioneering requirement for chain restaurants to flag salty items on their menus is both legal and beneficial, an appeals court said Friday, rejecting a restaurant-industry challenge to the rule.

The state Supreme Court Appellate Division decision, which upholds a lower court ruling, comes with many eateries already using the salt-shaker-like emblems, required for any dish with more than a full day’s recommended dose of sodium. But the National Restaurant Association has been fighting the 2015 regulation, and said Friday it was examining options for its next move.

At a time when federal health officials say 9 out of 10 Americans are eating too much sodium, raising risks of heart disease and stroke, the city says the warning symbols simply help diners see how salty some dishes can be. Even some fast-food salads can top 3,000 milligrams of salt; the recommended limit for a whole day is 2,300 mg, or about a teaspoon. The regulation applies to chains with at least 15 outlets nationwide.