Low-sodium diets not always worth their salt, McMaster study finds

Contrary to popular thought, maintaining alow-sodium dietmay not be beneficial to one's health. According to a recently published study, cutting down your daily saltintakecould actually be harmful to your body.

A recent global study conducted by researchers of the Population Health Research Instituteof McMaster University and Hamilton Health Sciences found low-sodiumdiets actually increase the risk of cardiovascular disease and deathcompared to diets withaverage sodium consumption.

The new study was published inThe Lancetmedical journalon Friday.

Everything in moderation

For years, Canadians have been told to avoid consuming too much sodium. While that still stands to be true, lead author AndrewMentesaid there's also another message that isn't usually heard: make sure you get enough sodium.

Salt is an essential nutrient and is needed by the body, said Mente, aprincipal investigator of the Population Health Research Institute and an associate professor of clinicalepidemiologyandbiostatisticsatMcMaster'sMichael G.DeGrooteSchool of Medicine in Hamilton.

If the body doesn't get enough of it, a variety of healthproblems couldresult, including an increased risk of heart attack andstroke.

Maintaining a moderate intake ofsodium each day is the healthiest choice for everyone, he said, including those who suffer from high blood pressure.

What does a moderate intake of sodiumlook like?

"Just follow an overall healthy diet, and don't be concerned about sodium," he said, adding the majority of Canadians are eating the right amount of sodium.

If you eat your fruits and vegetables,exercise,minimize processed foods and don't smoke,"you'll be fine, you don't even have to think about sodium," he said.

Dangers oflow-sodium diets

The study is very important for those who have high blood pressure,Mentesaid. The data highlights the importance forpeople with high blood pressure to reduce their salt intake, but also shows the dangers of going on a low-sodiumdiet.

• How much salt is too much?

According to the study, ahigh-sodium diet is onlylinked toan increased risk of cardiovascular disease in populations of people with high blood pressure.For people with a normalblood pressure, the study found ahigh-sodium diet was not associated with cardiovascular disease.

The study involved more than 130,000 people from 49 countries. It looked specifically athow the relationship between sodium intake and heart disease, stroke and death differedin people with high blood pressure as compared to those with normal blood pressure.

'The current guidelines need to be updated'

Mentesaid previous research that favouredlow-sodium diets was based on assumptionsaboutthe relationship between blood pressure and sodium levels.

"Given that lower sodium is related to lower blood pressure, theyassume that that's going to translate into lower cardiovascular disease," he said, speaking of past researchers."It turns out these assumptions are wrong."

• Canadians consuming sky-high amounts of sodium, study finds

Mentesaid that over the past five yearsnumerousstudies have revealed the dangers of low-sodium diets. This newest study at McMasterjust confirms what the latest research has shown, he said.

"It appears that low sodium truly is harmful and we need to be cautious before recommending low levels for the entire population," he said.

The current guidelines from Health Canada call for people to cut their salt intake to less than 2.3 grams per day, butMentesaidthese levels aretoo low.

"The current guidelines need to be updated to reflect contemporary research," he said.

Continuing debate

Between 2007 and 2010, Health Canada tasked aSodium Working Groupwith developing a population health strategy to help reduce sodium content in the diets of Canadians. The final report recommended Canadians aim for an intake level of 2.3 grams of sodium daily. At the time, the average daily sodium intake for Canadians was around 3.4 grams.

Mentesaid that currentlythe majority of individuals in Canada and in most other countries are consuming the right amount of salt between three and six grams daily.

• Sodium in 1 restaurant meal tops recommended daily intake

The debate stems from how researchers measure the overall health of a population. Some scientists think blood pressure is an infallible measure of predicting health effects,Mentesaid. They rely on the clinical trials of blood pressure measurements and then extrapolate that data.

Othersrely on measuring actual health events likeheart attacks, strokes and deaths. This is the process Mente and his team went through for their study.

To settle this debate,Mentesaidthere would likelyneed to be arandomizedcontrolled trial that would have torunfor years, holding participants strictly to a low-sodiumdiet. Thesetypes of trials are very difficult to run, he said, added that he hopes to take part in organizing one in the future.