Striking a Balance in Salt Consumption

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Restricting salt intake is considered a key component of heart failure treatment, but restricting it too much can actually worsen outcomes for people with a common form of the condition, suggests research published online in the journal Heart .

Younger people and those of black and other ethnicities appear to be at higher risk, the findings indicate.

Salt restriction is frequently recommended in heart failure guidelines, but the optimal range of restriction (less than 1.5 g to less than 3 g daily) and its effect in patients with heart failure with preserved ejection fraction is not established. of course, since they have often been excluded from relevant studies.

Heart failure with preserved ejection fraction , which accounts for half of all heart failure cases, occurs when the heart’s lower left chamber (left ventricle) cannot fill adequately with blood (diastolic phase), reducing the amount of blood pumped into the body.

In an attempt to further explore the association with salt intake, the researchers relied on a secondary analysis of data from 1,713 people aged 50 years or older with heart failure with preserved ejection fraction who were part of the TOPCAT trial.

A phase III, randomized, double-blind, placebo-controlled study, this trial was designed to find out whether the drug spironolactone could effectively treat symptomatic heart failure with preserved ejection fraction.

Participants were asked how much salt they usually added to cooking staple foods, such as rice, pasta, and potatoes; soup; meat; and vegetables, and this was scored as: 0 points (none); 1 (⅛ teaspoon); 2 (¼ teaspoon); and 3 (½+teaspoon).

Their health was then monitored for an average of 3 years for the primary endpoint, a composite of death from cardiovascular disease or hospital admission for heart failure plus aborted cardiac arrest. Secondary outcomes of interest were death from any cause and death from cardiovascular disease plus hospital admission for heart failure.

About half of the participants (816) had a cooking salt score of zero: more than half were men (56%) and the majority were white (81%). They weighed significantly more and had lower diastolic blood pressure (70 mm Hg) than those with a cooking salt score greater than zero (897).

They had also been admitted to hospital more frequently for heart failure, were more likely to have type 2 diabetes, poorer kidney function, be taking medications to control their heart failure, and have a lower left ventricular ejection fraction. reduced (lower cardiac output).

Participants with a cooking salt score greater than zero had a significantly lower risk of the primary endpoint than those whose score was zero, due primarily to the fact that they were less likely to be hospitalized for heart failure. But they were no less likely to die from any cause or from cardiovascular disease than those whose cooking salt score was zero.

People aged 70 and younger were significantly more likely to benefit from adding salt to their cooking than people aged 70 and older in terms of the primary endpoint and hospital admission for heart failure.

Similarly, people of black and other ethnicities seemed to benefit more from adding salt to their cooking compared to those of white ethnicity, although the numbers were small.

Sex, previous hospital admission for heart failure, and use of heart failure medications were not associated with increased risks for the outcomes measured and cooking salt score.

This is an observational study and as such cannot establish cause. Not all relevant data from the TOPCAT trial were available, while the cooking salt score was self-reported, the researchers acknowledge. And reverse causality cannot be ruled out, whereby people in poorer health might have been advised to further restrict their salt intake.

Lower sodium intake is generally associated with lower blood pressure and reduced risk of cardiovascular disease in the general public and in those with high blood pressure. It is believed to reduce fluid retention and the activation of hormones involved in regulating blood pressure.

But restricting salt intake to control heart failure is less straightforward, researchers say. It may cause intravascular volume contraction, which in turn may reduce congestion and the need for diuretics to relieve fluid retention.

But their study findings show that blood plasma volume , an indicator of congestion, was not significantly associated with cooking salt score, suggesting that low sodium intake did not alleviate fluid retention in people. with heart failure with preserved ejection fraction , the researchers note.

“Excessive restriction of dietary salt intake could harm patients with [heart failure with preserved ejection fraction] and is associated with a worse prognosis. “Doctors should reconsider giving this advice to patients,” they conclude.