Cutting back on salt 'may not lower heart risk'

Dramatically cutting the amount of salt in food might not protect against stroke and heart disease, a study claims.

By Nick Collins, Science Correspondent

In Caucasian people with normal blood pressure, a large reduction in the amount of salt they eat may actually do more harm than good, researchers said.

Reducing our salt intake is generally thought to protect the heart because it lowers our blood pressure, one of the leading risk factors for stroke and heart disease.

But a round-up of existing evidence published in the American Journal of Hypertension found that the moderate benefit to blood pressure could be cancelled out by increases in cholesterol and other harmful compounds.

Researchers from Copenhagen University Hospital in Denmark analysed 167 studies where participants reduced their salt intake by an average of 150 millimoles per litre – a much greater drop than health guidelines recommend.

In patients with high blood pressure this resulted in a drop of 3.5 per cent, but in people whose blood pressure was normal it fell by less than one per cent.

The modified diet also caused levels of cholesterol to rise by 2.5 per cent along with rises in certain hormones and chemicals linked to increased heart risk.

The findings question the idea that cutting back on salt would protect against stroke and heart disease in white patients whose blood pressure was already normal or low, the researchers said.

The results were not conclusive enough to show that Black or Asian people would experience the same effects, they added.

Dr Niels Graudal, who led the study, told Reuters: "I can't really see, if you look at the total evidence, that there is any reason to believe there is a net benefit of decreasing sodium intake in the general population."

Although cutting back on salt is known to reduce blood pressure, no study has shown beyond doubt that it can improve heart health in the general population.

While many governments, including Britain, recommend that people limit their salt intake, a number of recent studies have suggested there is no evidence that doing so can reduce the risk of heart problems.

But Prof Francesco Cappuccio of Warwick University, head of the World Health Organisation collaborating centre for nutrition, said the study was merely a "repackaged" version of previous research and failed to address previous criticism.

The study "should not distract our attention for implementing salt reduction policies at population level globally, as directed by national governments, the World Health Organization and the United Nations", he said.