In women with a high-sodium diet, every 1 g increase in daily potassium intake was associated with a 2.4 mm Hg lower systolic BP, according to data from a large cohort study.
In an analysis of long-term cohort data, researchers also found that women within the highest tertile of potassium intake had an 11% lower risk for incident and/or recurrent CVD events during nearly 20 years of follow-up compared with women with the lowest tertile of potassium intake, with a smaller but still significant CVD benefit observed for men.
“Most dietary advice is focused on sodium excess, yet we tend to ignore potassium,” Liffert Vogt, MD, PhD, an internist-nephrologist and full professor in nephrology at Amsterdam UMC and the University of Amsterdam, told Healio. “Our study shows that high daily potassium consumption might have a protective effect in terms of CV risk and mortality in a population with a very high background of sodium consumption. In light of the difficulties providers face in clinical practice restricting elements like sodium, calorie intake and saturated fats in the diet, adding or increasing intake of a healthy food ingredient like potassium might be very effective in reducing health risks.”
Liffert Vogt
Vogt and colleagues analyzed data from 11,267 men and 13,696 women participating in the Norfolk cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk) study, a prospective, population-based cohort study (mean age of men, 60 years; mean age of women, 59 years). Researchers collected spot urine samples to estimate 24-hour excretion of sodium and potassium, reflecting intake, and assessed the association between potassium intake, systolic BP and CVD events, defined as hospitalization or death due to CVD.
Interaction between potassium intake, BP
Within the cohort, 18.5% of men and 18.6% of women used antihypertensive medications. For men, estimated potassium intake was 2.8 g per day and estimated sodium intake was 4.9 g per day. For women estimated potassium intake was 2.6 g per day and estimated sodium intake was 4.2 g per day. The median spot urine sodium-to-potassium concentration was 1.7 in men and 1.5 in women.
Researchers found potassium intake was associated with systolic BP after adjustments for age, sex and sodium intake (P < .001), with significant interaction by sex (P < .001).
In women only, researchers observed an interaction by sodium intake (highest vs. lowest tertile) for the association between potassium intake and systolic BP (P < .001). In analyses stratified by sodium intake, an inverse association between potassium intake and systolic BP persisted only for those in the highest tertile of sodium intake (P < .001).
“In women within the highest tertile of sodium intake, every 1 g increase in daily potassium intake was associated with a 2.4 mm Hg lower systolic BP,” the researchers wrote.
Diet and long-term CV outcomes
During a median follow-up of 19.5 years, CVD events occurred in 54.5% of participants, including in 59.5% of men and 50.3% of women. For both men and women, a higher potassium intake was associated with lower risk for CVD events. In the overall cohort, the HR for CVD events in the highest tertile of potassium intake compared with the lowest was 0.87 (95% CI, 0.82-0.93). However, the HR associated with higher potassium intake was lower for women (HR = 0.89; 95% CI, 0.83-0.95) vs. men (HR = 0.93; 95% CI, 0.87-1; P for interaction by sex = .033).
For men and women, the association between potassium intake and CVD events was not modified by sodium intake.
“Potassium intake deserves more attention,” Vogt told Healio. “High potassium intake is a good marker for the amounts of healthy foods an individual consumes on a daily basis, including vegetables, legumes, fruits, nuts, dairy products and fish. Therefore, focusing on a varied diet rich in potassium, instead of solely providing advice with regard to sodium intake, is an easy step to implement.”
Vogt noted that the findings may apply more to women vs. men.
“In women, high potassium consumption is associated with a low BP and this effect seems to be the driving factor behind less CV problems on the long run,” Vogt said. “A new and surprising finding is that we did not observe any association between potassium and BP in men. In women, the effect of high potassium consumption was the largest in women that had the highest daily sodium consumption.
“Our study cannot claim any causal links; for this, we need a randomized controlled study,” Vogt told Healio. “We are currently conducting such a study in the Netherlands with people with chronic kidney disease. We also need more research on whether potassium alone, or the other healthy ingredients associated with a high-potassium diet, explain the beneficial effects that we found.”
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