Increased potassium intake vital for heart health in women

In the EPIC-Norfolk* study, a sex-specific association was found between daily potassium intake, systolic blood pressure (SBP), and cardiovascular disease (CVD). The findings particularly suggest that in women with high sodium intake, higher potassium intake was tied to lower SBP.

“It is well known that high salt consumption is associated with elevated BP and risk of heart attacks and strokes,” said study author Professor Liffert Vogt of Amsterdam University Medical Centers, the Netherlands, in a press release. “Potassium helps the body excrete more sodium in the urine. In our study, dietary potassium was linked with the greatest health gains in women.”

A total of 24,963 participants (n=11,267 [men] and 13,696 [women]; mean age 59 years) were evaluated. Sodium and potassium excretion (24-hour) were evaluated from sodium and potassium concentrations in spot urine samples, and further divided into tertiles (low/medium/high intake). [Eur Heart J 2022;43:2867-2875]

After adjusting for sex, age, and sodium intake, potassium intake was significantly associated with SBP (β=−0.8; p<0.001), with a significant interaction by sex (p<0.001). In women, the inverse slope between potassium intake and SBP was steeper among those within the highest vs lowest tertile of sodium intake (β=−2.4; p<0.001).

“In women within the highest tertile of sodium intake, every 1-gram increase in daily potassium intake was associated with a 2.4-mm Hg lower SBP,” said Vogt and colleagues.

More than half (54 percent) of participants had CVD events during a median follow-up of 19.5 years. In the fully adjusted model, those within the highest vs lowest tertile of potassium intake had a lower risk of CVD events (hazard ratio [HR], 0.87). When evaluating men and women separately, the reduction in risk of CVD events was greater in women than in men (HR, 0.89 vs 0.93; p_interaction=0.033).

“These results suggest that potassium helps preserve heart health, but that women benefit more than men,” said Vogt.

Beyond limiting salt

“[T]he beneficial effects of potassium may be attributed to increased potassium-mediated natriuresis and subsequent correction of a hypervolemic state,” the researchers explained. High potassium consumption leads to dephosphorylation of the sodium-chloride cotransporter (NCC). The ensuing reduction in NCC activity produces a net increase in sodium excretion. [Kidney Int 2013;83:811-824; Cell Metab 2015;21:39-50]

Interestingly, NCC expression is sex-dependent, they continued. In studies on rats, NCC density was higher in females than in males. [J Am Soc Nephrol 2017;28:3504-3517; J Am Soc Nephrol 1994;5:1112-1119]

Furthermore, ovariectomy in female rats reduced NCC expression and phosphorylation, underlining the involvement of female sex hormones in regulating NCC activity. [Am J Physiol Renal Physiol 2015;308:F799-F808] “[However,] given the mean age in our cohort, most women were presumably postmenopausal, indicating that other mechanisms leading to sodium sensitivity may also play a role,” they further noted.

“[Taken together,] our findings indicate that a heart-healthy diet goes beyond limiting salt to boosting potassium content. Food companies can help by swapping standard sodium-based salt for a potassium salt alternative in processed foods,” Vogt said. “On top of that, we should all prioritize fresh, unprocessed foods since they are both rich in potassium and low in salt.”