Low-salt diet linked to strokes, heart attacks

Salt - not the enemy? (Getty)
Salt - not the enemy? (Getty)

Unless you have high blood pressure, going for the low-salt option might not be the healthy choice.

In fact, for the average person a low-salt diet might increase the risk of heart attacks and strokes, new research has found.

Scientists in Canada looked at the salt intake and health of more than 130,000 people in 49 countries. They found no matter what a person's blood pressure was, consuming less than three grams of sodium a day was linked to increased cardiovascular risk and mortality.

And the harm caused by high sodium intake -- more than six grams a day -- was limited to those with high blood pressure, or hypertension.

"Low sodium intake reduces blood pressure modestly, compared to average intake, but low sodium intake also has other effects, including adverse elevations of certain hormones which may outweigh any benefits," says lead author Andrew Mente of the Population Health Research Institute at McMaster University Medical School, Canada.

"The key question is not whether blood pressure is lower with very low salt intake, instead it is whether it improves health."

The NZ Nutrition Foundation recommends no more than 2.3 grams of sodium a day, equivalent to six grams or one teaspoon's worth of salt. Fewer than 5 percent of people stay under that, according to the study, while the average Kiwi has about 50 percent more.

Dr Mente says this shows most Westerners are probably eating about the right amount, even if it's well above what health authorities recommend.

Only 10 percent of people had both high sodium intake and high blood pressure.

"This study adds to our understanding of the relationship between salt intake and health, and questions the appropriateness of current guidelines that recommend low sodium intake in the entire population," says co-author Dr Martin O'Donnell.

Instead of encouraging everyone to eat less salt, Dr Mente says authorities should focus on those who already have high blood pressure.

The findings have been published in medical journal The Lancet.