Aug. 14 (Bloomberg) — People who eat the least salt may be hurting their hearts, according to a study causing controversy because some of its findings clash with public-health efforts to lower sodium consumption.

The results published yesterday in the New England Journal of Medicine showed the expected link between heart complications and high levels of sodium, which is known to boost blood pressure and cardiovascular risks. Those at the lowest end, as measured by the amount of sodium in their urine, were also at greater risk — a 27 percent increased chance of heart attack, stroke and death from cardiovascular causes, the study found.

"There is a sweet spot for what the optimum sodium intake is," said Salim Yusuf, senior author of the paper and director of the Population Health Research Institute in Ontario. "The message is very simple: Moderation in salt intake. Avoid high and low levels."