Writing in the European Heart Journal, the UK/Dutch team concludes that the association between potassium intake, systolic BP (SBP), and cardiovascular disease (CVD) events is sex specific.
Delving deeper, the team suggests sex differences in sodium sensitivity, hypertension and chronic kidney disease (CKD) may explain interactions between potassium and sodium intake.
“The results suggest that potassium helps preserve heart health, but that women benefit more than men,” comments study author Liffert Vogt, Professor of Nephrology at the Amsterdam University Medical Centers in the Netherlands.
“The relationship between potassium and cardiovascular events was the same regardless of salt intake, suggesting that potassium has other ways of protecting the heart on top of increasing sodium excretion.”
Along with colleagues from the University of Cambridge, the team began an analysis on 11 267 men and 13 696 women that made up the EPIC-Norfolk cohort.
These subjects were 40–79-year-olds living in Norfolk, UK, between 1993 and 1997. The average age was 59 years for men and 58 years for women.
Participants completed a questionnaire on lifestyle habits, blood pressure was measured, and a urine sample was collected.
Twenty-four-hour excretion of sodium and potassium, reflecting intake, was estimated from sodium and potassium concentration in spot urine samples.
Participants were divided into tertiles according to sodium intake (low/medium/high) and potassium intake (low/medium/high).
The team then looked at the link between potassium intake and blood pressure after adjusting for age, sex and sodium intake.
Results revealed that in women as potassium intake (grams per day) went up, blood pressure went down.
When this finding was further scrutinised according to low/medium/high sodium intake, the relationship between potassium and blood pressure was only observed in women with high sodium intake.
The team observed that every one-gram increase in daily potassium consumed, a 2.4 mmHg lowering of systolic blood pressure was observed. In men, there was no association between potassium and blood pressure.
“Our findings indicate that a heart healthy diet goes beyond limiting salt to boosting potassium content,” adds Professor Vogt.
“Food companies can help by swapping standard sodium-based salt for a potassium salt alternative in processed foods.
“On top of that, we should all prioritise fresh, unprocessed foods since they are both rich in potassium and low in salt.”
During a median follow-up of 19.5 years, 13,596 (55%) participants were hospitalised or died due to CVD.
The researchers analysed the association between potassium intake and cardiovascular events after adjusting for age, sex, body mass index, sodium intake, use of lipid lowering drugs, smoking, alcohol intake, diabetes and prior heart attack or stroke.
In the overall cohort, people in the highest tertile of potassium intake had a 13% lower risk of cardiovascular events compared to those in the lowest tertile.
When men and women were analysed separately, the corresponding risk reductions were 7% and 11%, respectively.
The amount of salt in the diet did not influence the relationship between potassium and cardiovascular events in men or women.
“Considering the lack of interaction with daily sodium intake in our study, other cardiovascular protective effects of potassium may be involved as well,” the team writes.
“These effects presumably relate to the antioxidant and vasoactive properties of potassium.”
“Observations indicate that potassium might play an important role in cardiovascular health beyond its natriuretic effects, explaining the sodium-independent inverse association between potassium intake and CVD events.”
Source: European Heart Journal
Published online: doi.org/10.1093/eurheartj/ehac313
“Sex-specific associations between potassium intake, blood pressure, and cardiovascular outcomes: the EPIC-Norfolk study.”
Authors: Rosa Wouda et al.