Sodium levels in many foods served at Canadian restaurant chains exceed the amount an adult should take in during a day, a new study finds.

Researchers examined the salt levels in more than 9,000 foods sold at 65 fast-food restaurants and 20 sit-down restaurant chains with at least 20 locations across the country.

Considering how common it is to dine out, along with the pervasiveness of hypertension and its health risks, the study authors said it was important to take a systematic look at sodium levels to assess progress towards the federal, provincial and territorial target of lowering sodium intake to 2,300 milligrams per person per day by 2016.

It is recommended that adults eat up to 1,500 milligrams of sodium per day, which is called the daily adequate intake (AI) level that Health Canada says is expected to meet or exceed the needs of most individuals.

People aged 14 and older should not eat more than 2,300 mg sodium per day or about a teaspoon of salt — the daily tolerable upper intake level or UL, as that level is likely to pose a health risk.

Sandwiches, wraps, stir fry entrees and ribs topped the sodium levels at sit-down restaurants. (Graham Hughes/Canadian Press)

More than 22 per cent of sandwiches or wraps, ribs and pasta entrees with meat or seafood exceeded the UL for sodium at sit-down restaurants. On average, meal items not including side dishes contained 1,455 milligrams of sodium per serving or 97 per cent of an adult's daily AI. Seafood, beef and salad entrees were the categories with the lowest sodium levels per serving.

At fast food restaurants, the highest categories were stir fry entrees, poutine or fries with toppings, tacos and burritos, sandwiches or wraps and salads with meat or seafood.

Study authors Mary L'Abbé, chair of the nutritional sciences at the University of Toronto, and graduate student Mary Scourboutakos took the systematic look at sodium levels provided by industry in 2010 and early 2011.

Since Canada has not yet established targets or implemented a reduction strategy for the restaurant sector, L'Abbé and Scourboutakos used the U.S. targets.

Searching out healthier options

"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," they concluded in Wednesday's issue of the Canadian Journal of Public Health.

The majority of establishments exceeded targets for sodium density in baked goods such as bagels, croissants and cookies, fried potatoes, other sandwiches, fries, sandwiches with luncheon meat and pizza.

Because of the high sodium density, reducing portion sizes alone won't work to meet the targets, the researchers said.

Fries with toppings from fast food chains had more than 1,500 milligrams of sodium. (Peter Dejong/Associated Press)

L'Abbé had a few suggestions for consumers looking for lower sodium options when eating in restaurants.

"First, they can ask restaurants if they have lower sodium offerings, because if you go out and eat out and consumers start asking for lower sodium offerings, I think they will hear us. When you actually taste something and it tastes too salty, tell them."

Asking for sauces and dressings on the side also helps, she said. Items that may seem healthier, like salads, aren't necessarily the best option. Diners also need to consider other nutritional aspects like saturated fat and sugar.

At the Nota Bene restaurant in Toronto, executive chef David Lee offers lunch menu items that cut back on salt, such as grilled organic salmon on salad.

"It's a healthier option," Lee said. "For me, that would involve, in terms of the sodium, maybe cut back just a little bit and implement maybe some more herbs or a little bit more olive oil."

For children's items, on average the items contained 65 per cent of the daily recommended amount of sodium — 1,200 milligrams for those aged four to eight. L'Abbé said it shows the need to establish targets specifically for children. Previous research suggests teens who often eat fast food may alter their taste perception, promoting a preference for salt, but that reductions aren't easily detected when introduced slowly.

The researchers acknowledged that they relied on food establishments to provide accurate data and that sodium levels could vary. They called for more research to see how much market share influences the results.

At a Jack Astor's Bar & Grill, one of the chains in the study, Myles Sam said the restaurant is trying to use less salt.

"We leave it to the guest," said Sam, the assistant kitchen manager. "There's salt on the table if you want to add more."

The Centre for Science in the Public Interest estimated that three-quarters of the excess sodium in the Canadian food supply is added by food manufacturers and restaurants.

Next month, a vote is expected on federal NDP health critic Libby Davies' private member's bill, which requires food manufacturers to meet sodium reduction targets.

The Canadian Restaurant and Foodservices Association is opposed to the bill, saying that restaurants are already working closely with suppliers to reduce sodium levels in menu items.

The research was funded by the Canadian Institutes of Health Research, Canadian Stroke Network and the University of Toronto.

With files from CBC's Kim Brunhuber