On an epidemiologic basis, it is clear that for most populations there is a linear risk between levels of salt intake and cardiovascular (CV) endpoints, directly related — it appears — through the impact on blood pressure (BP). While it is intuitive as well as enticing to assume that the linear relationship between salt-BP-CV disease should be a two-way street, convincing proof of that has been remarkably elusive; that is, we do not have evidence from a large, randomized clinical trial proving that dietary sodium reduction improves CV outcomes. Nonetheless, since there is no suggestion that elevated ingestion of sodium is a health benefit, most experts advocate that a population-wide reduction in sodium, most of which excess comes from processed foods with lesser nutritional value than fresh food, would be a good thing.
There are, however, flies in the ointment. For instance, some individuals appear to ingest large amounts of sodium without incurring BP increases. Why that might be was explored by Rodrigues et al in a population of Brazilians (n = 1285). Investigators compared the amount of salt intake per day and evaluated potassium intake with the hunch that higher potassium levels in the diet might protect against sodium-induced elevations in BP. Their supposition was quite sensible based on two earlier population studies which found that BP was inversely associated with dietary potassium intake.
Among persons consuming high levels of sodium (> 6 gm/d), those in the top quartile sodium/potassium ratio had mean SBP 8 mmHg higher than the lowest quartile. Similarly, the highest quartile of dietary potassium intake had SBP that was 6 mmHg lower than the lowest quartile.
Having a strong component of potassium in the diet appears to mitigate sodium-associated elevations in BP.
Source: Rodrigues SL, et al. J Am Soc Hypertens 2014;8:232-238.