Salt intake is difficult for individuals to control, because more than three quarter of the salt we consume comes from processed foods, like bread, deli meats and dairy products.
Most Canadians are consuming more than double the daily recommended amount of salt.
While there is a link between salt consumption and heart disease and stroke, the evidence that lowering salt intake improves health is not as clear as the evidence that reducing obesity or high cholesterol improves health.
How Much Salt are we Consuming?
Salt is an important nutrient for the body and helps regulate fluids, blood volume and blood pressure. Salt occurs naturally in many of the foods that we eat. While salt is important for functioning, consuming too much can lead to increased blood pressure. High blood pressure is a major risk factor for heart disease, stroke and chronic kidney disease, which are leading causes of death in Canada.
Although the amount of salt we add to our food as table salt is important, we do not have direct control over the majority of salt in the food we eat.
The average Canadian consumes about two teaspoons of salt per day, which is more than double the Health Canada daily recommended amount of 1500 mg, or about ¾ of a teaspoon. Currently, the daily recommended amount is unrealistic given how little control Canadians have over the salt we eat. 77% of the average Canadians’ salt intake comes from commercially processed foods – where salt is added by food manufacturers and restaurants before it even arrives on our plates. In fact, just 11% of our salt intake comes from adding it ourselves – with 5% of overall intake coming from the salt shaker, and 6% coming from adding salt to foods while cooking. Twelve percent of intake comes from eating non-processed foods, like vegetables, which contain naturally-occurring salt.
Recognizing the major contributors of salt to Canadian’s diet, a Health Canada Sodium Working Group recommended establishing a more realistic, interim goal of Canadians reducing salt intake to 2300 mg per day.
You may be surprised by the graph below which highlights research about what food sources in Canadians’ diets are the major contributors to salt intake. The study asked 35000 Canadians to recall what they had eaten in a 24 period of time, and found that breads, processed meats and pasta dishes are the highest sources of salt in our diets. Breads and pasta are consumed in large amounts and so while they may not be as salt-dense as processed meats, they still make up a significant chunk of salt intake.
What are the Health Consequences of Excess Salt?
Given that high salt consumption leads to high blood pressure especially in some individuals, it is no surprise that 20% of the adult population in Canada has high blood pressure, and another 20% percent are classified as pre-hypertensive (having higher than normal blood pressure), which predisposes them to a higher risk of heart disease and stroke.
Canadians are familiar with the health risks of salt, with 74% indicating that they are very or moderately concerned about salt in their diets. The same survey also notes that when asked about efforts to improve eating habits, 27% responded that they were eating more fruits and vegetables, 17% said cutting down on fatty foods and only 12% responded about reducing salt intake. While Canadians are familiar with the public health message that salt consumption leads to high blood pressure, it is difficult to reduce in our diets, and very few Canadians are doing this.
Every seven minutes in Canada, someone dies from heart disease or stroke, which represents the second and third leading three causes of death nationally. Heart disease and stroke are also the leading cause of hospitalization, accounting for 17% of all hospital admissions. Kevin Willis, director of partnerships for the Canadian Stroke Networks says that “reducing salt in the food supply is one of the few relatively easy wins we have to reduce the burden of chronic disease on our health care system.”
However, some experts like Steven Grover, a general internist and researcher at McGill University in Montreal suggest that it is not so simple. Grover argues that “population interventions to reduce salt intake are unrealistic in terms of feasibility and are based on a selective interpretation of the evidence.”
The great salt debate
While the link between salt consumption and high blood pressure has been demonstrated through high quality peer reviewed studies, there are no clinical trials which have demonstrated that reducing salt consumption population-wide decreases the frequency of heart disease and stroke. Because of this, there is a debate about whether there is enough evidence to support population wide interventions, like reducing the amount of salt in foods.
Yoni Freedhoff, an obesity specialist in Ottawa says that “just because we cannot demonstrate something conclusively” does not mean that efforts to reduce salt are misplaced, and he argues that “we don’t have the luxury of waiting when it comes to the relationship of diet to chronic disease.” Freedhoff goes on to argue that “there is no risk in reducing dietary salt, which seems like a fair target given that around one half of the population, will eventually develop a salt responsive disease.”
However, the debate about how aggressively we attempt to reduce salt intake has implications far beyond the scientific community.
The food industry & reducing salt
A panel of experts in salt convened by the World Health Organization suggest that “interaction with food manufacturers is fundamental to the success of salt reduction strategies”
However, the food industry fears that reducing salt will make their products less tasty, thus markedly reducing their profits. For example, Campbell Soup Company announced in July 2011 that it would be adding back salt to their products sold in the United States where it had been previously reduced, amidst reports of declining sales.
Food manufacturing is a very powerful lobby in Canada, providing hundreds of thousands of jobs and billions of dollars to the economy each year. In Ontario, food processing is an important industry which accounts for annual sales of $32.3 billion. Kevin Willis says reducing salt in manufactured foods “is a highly politically and economically important issue in Canada, with some groups and parties having major vested interests in maintaining the status quo.”
Part two of this series will explore the opportunities and challenges around government regultion of salt in foods.