Sodium levels in most foods served at chain restaurants in Canada have stayed the same over three years, say nutrition researchers calling for government-enforced action to reduce sodium.

Reducing sodium levels is a public health priority, researchers say, since consuming too much can push up blood pressure and increase the risk of heart disease and stroke.

In Tuesday’s issue of the CMAJ Open, researchers report the number of menu items with "unacceptably high amounts of sodium" did not change from 2010 to 2013.

Mary L’Abbé and Mary Scourboutakos of the nutritional sciences department at the University of Toronto concluded that sodium levels:

  • Decreased in 30.1 per cent of foods.
  • Increased in 16.3 per cent.
  • Remained unchanged in 53.6 per cent.
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The number of restaurant foods containing a 'healthy' amount of sodium has not increased, researchers found. (Gene J. Puskar/Associated Press)

"More pressure needs to be put on restaurants to lower sodium because clearly right now, not enough progress is being made and labelling legislation might be one way to achieve that," Scourboutakos said.

In the U.S., she added, evidence suggests when restaurants were forced to put sodium information on their menus, they lowered salt levels.

The study compared sodium levels in more than 2,100 foods based on nutrition data from the websites of 61 restaurants with 20 or more locations across Canada.

Voluntary reductions

Sodium levels at restaurants such as Subway, Pizza Hut, Taco Bell and Taco Time decreased by at least 20 per cent in more than 70 per cent of foods surveyed. But large reductions in certain foods masked increases in others to offset the improvements, the researchers said.

The number of foods containing a "healthy" amount of sodium did not increase.

Currently, 85 per cent of men and up to 83 per cent of women exceed the daily sodium level likely to pose a health risk — 2,300 milligrams, the researchers said, pointing to a 2007 survey by Health Canada.

The goal is to work towards reducing the average intake of Canadians to 2,300 milligrams per day by 2016, Health Canada's website says.

Restaurants Canada represents restaurants including A&W, Dairy Queen, Harvey’s, McDonald’s, Milestones, Pizza, Quiznos, Swiss Chalet and Tim Hortons.

Joyce Reynolds, executive vice-president of government affairs for the industry group, said the study doesn't look at overall sodium reductions in restaurants or if the items are ordered frequently.

Reynolds said restaurants are prepared to work with governments to help Canadians get the message about sodium reduction, but consumers also need to accept sodium-reduced foods.

In August, Restaurants Canada said 17 chains have committed to implement its national voluntary program via pamphlets highlighting calorie and sodium content by the end of the year.