Less sodium equals healthier hearts

A University of Calgary researcher translates sodium research into health policy

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According to a 2004 survey, Canadian adults consume about 3,092 mg of sodium per day, more than twice the amount they actually need. High sodium intake contributes to high blood pressure, which is a risk factor for heart disease. But what would happen if Canadians actually cut back on the amount of salt they ate? Based on the predictions of Dr. Norm Campbell and his colleagues, Canadians could reduce the prevalence of hypertension by 30% and lower their risk of heart disease and stroke.

Dr. Campbell, a researcher at the University of Calgary, has used mathematical models to predict the long-term impacts of population-wide changes in sodium intake. Now he is translating his findings into new tools and policies to reduce Canada's sodium intake.

After receiving the Canadian Institutes of Health Research (CIHR) Canada Chair in Hypertension Prevention and Control, Dr. Campbell began a series of studies that attempted to determine how much damage the excess sodium in our diets was doing, and what would happen if we made population-wide reductions in our sodium intake.

"Our model predicted that lowering Canadians' sodium intake to just above the Adequate Intake level (1,500 mg per day) would reduce the number of people with hypertension by about 30%, which is over a million Canadians," says Dr. Campbell. "It would also reduce visits to doctors' offices for hypertension by about 5 million a year. It would have saved between $430 and $540 million a year (based on data from 2003) just in hypertension-related management costs."

In a second study, Dr. Campbell and his colleagues examined how reducing dietary sodium would impact the rate of cardiovascular disease in Canada.

"Based on our model's predictions, it appears that the sodium reduction could reduce the annual incidence of cardiovascular events (such as heart attacks and stroke) by about 13%," says Dr. Campbell.

If these calculations hold true, Canadians could benefit enormously, both in terms of improved health and health-care savings, by simply reducing how much salt we eat. The greatest source of sodium in our diet is the salt added during food processing, so Dr. Campbell and others are working with food manufacturers and the Canadian Government to oversee a process to reduce salt in Canadian food sources.

"In 2006 we began the Sodium Strategic Planning Committee, which consisted of eight national organizations and developed a policy statement that outlined different actions that would be required from government, industry and healthcare professional organizations to reduce dietary sodium," says Dr. Campbell.

That, in part, led to the creation of the Health Canada Sodium Working Group (SWG) of which Dr. Campbell is a member. The SWG is now developing a strategy to lower the sodium content of Canadians' diets. The group is taking a three-pronged approach to sodium reduction that includes research, education and voluntary reduction of sodium in processed food products and foods sold in foodservice establishments. Dr. Campbell is also collaborating with about 40 health-care volunteers to create tools and resources to help policy-makers and health-care professionals assist people trying to reduce the amount of salt in their diet.

"The project is really moving into a much bigger platform," says Dr. Campbell. "This will really be a huge national program focused on reducing dietary sodium with an evaluation component built in that will allow us to examine where the program is working, where it is not working, and what needs to be improved."

"Dr. Campbell, as the CIHR Chair in Hypertension Prevention and Control, has provided both science and leadership in Canada's sodium reduction effort. His energy and commitment will help quell cardiovascular disease and its complications, which represents the number one chronic disease burden in Canada."

Dr. Peter Liu
Scientific Director
CIHR Institute of Circulatory and Respiratory Health