Changes in sodium levels in chain restaurant foods in Canada (2010-2013): a longitudinal study.

BACKGROUND: Several restaurant chains have committed to reducing sodium levels in their foods; however, how much sodium levels have changed over the past few years is unknown. The objective was to measure changes in sodium in restaurant foods from 2010 to 2013.
METHODS: Data for the serving size, calorie and sodium level of 3878 foods were collected from the websites of 61 Canadian restaurant chains in 2010 and 2013. A longitudinal study of changes in sodium levels in foods available from the restaurants in 2010 and 2013 (n = 2198) was conducted. Levels in newly reported and discontinued foods were also investigated.
RESULTS: Sodium levels (mg/serving) decreased in 30.1% of foods, increased in 16.3% and were unchanged in 53.6%. The average change in foods with a decrease in sodium was -220 (standard deviation [SD] ± 303) mg/serving (a decline of 19% [SD ± 17%]), whereas the average change in foods with an increase in sodium was 251 (SD ± 349) mg/serving (a 44% [SD ± 104%] increase). The prevalence and magnitude of change varied depending on the restaurant and food category. Overall, there was a small, yet significant, decrease in sodium per serving (-25 [SD ± 268] mg, p < 0.001); however, the percentage of foods exceeding the daily sodium adequate intake (1500 mg) and tolerable upper intake level (2300 mg) remained unchanged.
INTERPRETATION: The observed increases and decreases in sodium show that industry efforts to voluntarily decrease sodium levels in Canadian restaurant foods have produced inconsistent results. Although the lower levels in some foods show that sodium reduction is possible, the simultaneous increase in other foods demonstrates the need for targets and timelines for sodium reduction in restaurants.