TORONTO — A pair of large international studies are questioning the validity of the notion that the less salt a person consumes, the better. In fact, the Canadian-led research suggests too little salt in the diet may even be a bad thing.
The studies, published Wednesday in the New England Journal of Medicine, involved more than 100,000 people in 18 countries and assessed daily sodium and potassium intake, relating them to blood pressure levels and to the risk of heart disease, strokes and deaths.
On average, Canadians ingest between 3.5 and four grams of sodium per day, but some guidelines have recommended lowering daily intake to less than 2.3 grams per day, a level the researchers say has been attained by less than five per cent of the population, both in Canada and around the world.
In 2010, a 25-member sodium working group chaired by Health Canada advised Canadian adults to try to cut salt consumption by a third so they could reach a maximum of 2.3 grams a day by 2016. The group said 1.5 grams daily is considered adequate intake.
Hypertension Canada an organization of about 70 health professionals from across the country, had recommended that teens and adults limit sodium intake to between 1.2 and 1.5 grams, depending on age. But last October, it raised that amount to two grams, the equivalent of roughly five millilitres (one teaspoon) of salt, after reviewing the latest research on the effects of dietary sodium on blood pressure.
The Prospective Urban Rural (PURE) study, led by investigators at McMaster University, shows that a dietary sodium level exceeding five grams per day does indeed raise blood pressure, especially among people who already have hypertension and those age 55 and older. High blood pressure, or hypertension, is a known risk factor for heart attack, heart failure, stroke and other disorders.
But cardiologist Dr. Salim Yusuf, principal researcher of the two studies, said the effects of blood pressure are more modest at average levels of sodium consumption — three to five grams per day — and not obvious at amounts below three grams, which is under the maximum intake recommended by many guidelines.
“It makes sense if your blood pressure is high, your sodium intake is high, to lower sodium,” Yusuf said Wednesday from Hamilton, Ont. “But what is often ignored is that increasing your potassium intake by eating healthy foods is also beneficial and just as important, and the two together is your best strategy.”
Bananas, avocados, sweet potatoes, green leafy vegetables and legumes are just some of the foods rich in potassium.
“A balanced approach is what is likely to have the greatest benefit in lowering blood pressure,” said Andrew Mente, an assistant professor of clinical epidemiology and biostatistics, and lead author of the first paper. “This can be achieved by moderation in salt intake, combined with eating lots of fruits and vegetables.”
an organization of about 70 health professionals from across the country, had recommended that teens and adults limit sodium intake to between 1.2 and 1.5 grams, depending on age. But last October, it raised that amount to two grams, the equivalent of roughly five millilitres (one teaspoon) of salt, after reviewing the latest research on the effects of dietary sodium on blood pressure.
The Prospective Urban Rural (PURE) study, led by investigators at McMaster University, shows that a dietary sodium level exceeding five grams per day does indeed raise blood pressure, especially among people who already have hypertension and those age 55 and older. High blood pressure, or hypertension, is a known risk factor for heart attack, heart failure, stroke and other disorders.
But cardiologist Dr. Salim Yusuf, principal researcher of the two studies, said the effects of blood pressure are more modest at average levels of sodium consumption — three to five grams per day — and not obvious at amounts below three grams, which is under the maximum intake recommended by many guidelines.
“It makes sense if your blood pressure is high, your sodium intake is high, to lower sodium,” Yusuf said Wednesday from Hamilton, Ont. “But what is often ignored is that increasing your potassium intake by eating healthy foods is also beneficial and just as important, and the two together is your best strategy.”
Bananas, avocados, sweet potatoes, green leafy vegetables and legumes are just some of the foods rich in potassium.
“A balanced approach is what is likely to have the greatest benefit in lowering blood pressure,” said Andrew Mente, an assistant professor of clinical epidemiology and biostatistics, and lead author of the first paper. “This can be achieved by moderation in salt intake, combined with eating lots of fruits and vegetables.”