Increased blood pressure and greater risk for heart problems has been linked to high salt intake, but new research is showing that low salt intake may be just as harmful. The Lancet published a study that found low salt or sodium intake may raise the risk of heart attack, stroke and even death, compared with an average salt intake.
Andrew Mente of the Michael G. DeGroote School of Medicine at McMaster University in Canada and lead author, along with his colleagues, say that their results indicate only those with high blood pressure who have a high salt intake should reduce their salt consumption. They further suggest that current recommendations for daily salt consumption may be set too low. Less than 2,300 milligrams of sodium each day (equivalent to 1 teaspoon of salt) has been recommended by The Dietary Guidelines for Americans.
A report earlier this year from the Centers for Disease Control and Prevention (CDC) revealed that about 90% of Americans consume salt at levels above the recommended limit. Too much salt in the diet can lead to high blood pressure and increases the risk for heart attack, stroke and other cardiovascular diseases.
Mente and colleagues set out to investigate if reducing salt intake to the recommended levels in current guidelines really does reduce the risk of such outcomes. The risks of high salt intake were only found in people with hypertension when they looked at the sodium intake of participants. In fact, compared with people who had an average sodium intake, the rates of heart attack, stroke and death were actually higher among those who had a low sodium intake, no matter if they had high blood pressure or not.
A low salt intake was defined in the study as the intaking of less than 3,000 milligrams a day, which is above current recommendations. Only those individuals with high blood pressure appeared to be subject to the risks associated with high salt intake. These findings are very important for all individuals with high blood pressure, even though it does not support reducing salt intake to low levels.
Mente suggests strategies to reduce salt consumption should be targeted at those with high blood pressure who have a high salt intake. They also believe the results indicate the current daily recommendation for salt intake may be set too low.
The study co-author, Martin O’Donnell of McMaster University and the National University of Ireland Galway, questions the appropriateness of current guidelines that recommend low sodium intake in the entire population. He feels that an approach that recommends salt in moderation, particularly focused on those with hypertension, appears more in-line with current evidence.
–Dr Fredda Branyon