Daily sodium intake over 1,500mg linked to higher stroke risk

In advance of the publication of the USDA’s Dietary Guidelines for Americans, the American Heart Association (AHA) recommended that sodium consumption should be lowered to a maximum of 1,500mg for all Americans, based on the relationship between sodium intake and high blood pressure, but the researchers behind this latest study said that there were “gaps in the literature” linking sodium with cardiovascular disease and stroke.

The researchers, from the University of Miami and New York’s Columbia University Medical Center, looked at dietary sodium intake and stroke incidence for 2657 participants of the Northern Manhattan Study over a period of ten years. They found that 235 strokes occurred during this period, with the highest sodium consumption associated with the highest risk of stroke.

“Our study provides evidence for a strong relationship between excess sodium intake and increased stroke risk in a multiethnic population,”​ the study’s authors wrote.

Higher intake, higher risk​

High sodium intake was prevalent in the study population, with 88% consuming more than the AHA’s recommended limit, and a 17% increase in stroke risk for each 500mg per day increase in sodium consumption, they found. Those who consumed more than 4000mg of sodium per day (21% of participants) had a 2.6-fold increased stroke risk compared to those consuming less than 1,500mg.

Based on analysis of food frequency questionnaires, 43% of study participants consumed between 2,300mg and 4,000mg of sodium per day, and 24% consumed 1,500mg-2,300mg. In the latest Dietary Guidelines for Americans, the USDA recommends a 1,500mg limit for those with, or at risk of developing, hypertension – about two-thirds of the US population – and a 2,300mg for those not considered at risk.

‘Beneficial for all’​

“Our study supports the importance of reducing sodium consumption to [a maximum of 1,500mg a day] for most Americans,”​ the researchers wrote. “The association between sodium consumption and stroke risk was independent of behavioral and vascular risk factors, including hypertension, at baseline, and was observed among those with and without hypertension and across age groups, suggesting that lowering sodium consumption can have beneficial effects on stroke risk for all.”​

They found that those who consumed the least sodium were more likely to be older, women, black, non-smokers, or those taking antihypertensive medications. Those consuming the most sodium were more likely to be Hispanic, heavier, or moderate alcohol users, and higher sodium intake was also associated with higher consumption of total calories, protein, carbohydrates, total fat, and saturated fat.

Source: Stroke​

2012, Vol. 43, pp. 1200-1205 DOI: 10.1161/STROKEAHA.111.641043

“​Dietary Sodium and Risk of Stroke in the Northern Manhattan Study”​​

Authors: Hannah Gardener, Tatjana Rundek, Clinton B. Wright, Mitchell S.V. Elkind and Ralph L. Sacco