Sodium Intake: How Low Should You Go?

By Ruth Kava — Apr 27, 2017
There are probably few, if any, nutritional advisories that are as hotly debated as the appropriate level of sodium intake for healthy adults. Yes, the Dietary Guidelines and the American Heart Association recommend an upper limit of 2,300 mg sodium per day (about a teaspoon). But some new research is being added to the literature indicating that level of restriction may be too strict.
Pouring the Salt

As we've noted before, the amount of sodium an adult should consume has been, and still is, a bone of contention, with some experts finding that current recommendations (less than 2300 mgm/day) are off the mark (too low) and that other dietary items, such as potassium, should be given more attention. Along these lines is a new report presented at the Experimental Biology Meetings by Dr. Lynn L. Moore from the Boston University School of Medicine.

It has been reported that Dr. Moore and colleagues analyzed information from the Framingham Heart Study's Offspring Cohort (1) for possible associations between sodium intake and blood pressure. The subjects included over 2600 healthy men and women between the ages of 30 and 64 years. Their daily sodium and potassium intakes were obtained from dietary intake data, and categorized as low (less than 2500 mgm and 2300 mgm respectively) or high (over those amounts).

On average, the participants in the high intake categories for both minerals had blood pressures of 120/76 mg HG (normal), while the average was 135/79 mg HG for those in low groups — they were followed for 16 years. Surprisingly, those with highest combined intakes of sodium and potassium actually had the lowest overall blood pressures.

Dr. Moore suggested that an intake of 3 to 4 grams (3000-4000 mg) of salt per day is more realistic and appropriate for healthy adults, while acknowledging that this range might not be appropriate for people with existing high blood pressure (now considered to be more than 140/90).

Now, while these results are fascinating, and add to a growing body of research that seems to undercut the 2300 mg sodium guideline, a couple of caveats must be mentioned. First, these are preliminary results — that's the nature of scientific meetings. They provide a gathering where scientists can present and discuss current research with their peers. The results still have to be written up in a formal format, pass peer review and be published in a journal. Second, these results are based on dietary data — not necessarily the most accurate estimate of sodium intake.

So, before you twist yourself into a pretzel to meet the 2300 mg guideline (if you have normal blood pressure), you may be excused for taking that guideline with just a grain of salt. And stay tuned for more research along these lines before the next iteration of the Dietary Guidelines for Americans is published for 2020-2025.

(1) The Framingham Offspring Cohort Study began in 1971 with about 5100 men and women who were the children of the original Framingham Heart Study.