Poster Presentation Joint Annual Scientific Meeting of the Nutrition Society of NZ and the Nutrition Society of Australia

Sodium, potassium and blood pressure in adults (#P66)

Claire Larter 1 , Dorothy Mackerras 1
  1. Food Standards Australia New Zealand, Canberra, ACT, Australia

Introduction: Existing reviews of the sodium-blood pressure and potassium-blood pressure relationships were updated to assess whether reported relationships existed in both normotensive and hypertensive subjects. 

Methods: The existing reviews selected used similar inclusion criteria such as randomised controlled trials lasting at least four weeks and reporting blood pressure. Both reviews examined resting blood pressure as the main endpoint. Their search strategies were replicated in the same databases to include more recent literature in June and August 2013 for the potassium and sodium reviews respectively. A quantitative meta-analysis tested for sub-group differences by blood pressure status. 

Results: One new sodium study conducted in hypertensive people reported a significant reduction on resting blood pressure. It did not alter previous conclusions that there is a relationship in both normotensive and hypertensive groups. One new potassium study conducted in normotensive people (no effect) could not be added to the meta-analysis because only ambulatory blood pressure was reported. Despite this, the existing review of resting blood pressure was re-analysed to remove some errors. This did not alter the overall results.  There was a significant interaction by population subgroup with an effect seen only in hypertensive people. However, only two studies reporting resting blood pressure were conducted in normotensive people.   

Conclusions: In studies lasting at least four weeks, reducing sodium intake reduced blood pressure in both normotensive and hypertensive people although the magnitude of effect was less in normotensive people. For potassium, there is insufficient data to draw a firm conclusion in normotensive people.

Funding source: none