Study Calls Dietary Sodium Recommendations Into Question

Lower sodium consumption is not associated with lower blood pressure, according to the results of a recent study that calls into question the recommended daily sodium limits from the Dietary Guidelines for Americans.

The current guidelines recommend limiting sodium intake to 2.3 g/day for healthy individuals under the age of 50 years, and 1.5 g/day for adults older than 50 years, African-Americans, and individuals with high blood pressure, diabetes, or chronic kidney disease. However, recent research has questioned these guidelines, identifying the need to consider intake of other minerals as well as sodium.
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For their study, researchers examined data from 2632 individuals, aged 30 to 64 years, who participated in the Framingham Offspring Study. All participants had normal blood pressure at baseline. The researchers collected detailed dietary records, using these to assess the long-term effects of dietary sodium on blood pressure over 16 years of follow-up.

Despite the expectation that higher dietary sodium would be associated with higher blood pressure, they found the opposite to be true, with systolic blood pressure levels decreasing across quintiles of increasing sodium intake. Similar results were observed for diastolic blood pressure.

Dietary potassium, calcium, and magnesium were inversely associated with blood pressure levels. Overall, those with the lowest blood pressure levels at the end of follow-up were individuals with higher intakes of both sodium and potassium, and those with the highest blood pressure levels were individuals with lower intakes of sodium and potassium.

“These long-term data from the Framingham Study provide no support for lowering sodium intakes among healthy adults to below 2.3 g/day as recommended. This study does support the finding of a clear inverse association between potassium, magnesium, and calcium and blood pressure change over time,” the researchers concluded.

—Michael Potts

Reference:

Moore LL, Singer MR, Bradlee ML. Low sodium intakes are not associated with lower blood pressure levels among Framingham offspring study adults. FASEB J. 2017;31(1):Supplement 446.6.