Beyond the Headlines: Insights on Potassium Supplementation for the Treatment of Hypertension from the CHEP Guidelines

The Canadian Hypertension Education Program (CHEP) guidelines are the first major recommendations that incorporate the Systolic Blood Pressure Intervention Trial (SPRINT) results for clinical practice. While these changes will certainly have a major impact on the treatment of blood pressure for individuals with a high cardiovascular disease (CVD) risk, what may be equally noteworthy though seemingly less provocative is the recommendation for the non-pharmacological treatment of blood pressure with dietary potassium intake for patients who are not at high risk for hyperkalemia.¹

Increased potassium intake is included as a healthy behavior and receives the only Grade A recommendation in this section other than sodium reduction. The CHEP guidelines base their recommendation largely on the evidence from a meta-analysis of 22 studies in which potassium supplementation reduced systolic blood pressure (SBP) by 3.5 mmHg and diastolic blood pressure by 2.0 mmHg.² However, participants with hypertension had a SBP reduction of 5.3 mmHg, those taking anti-hypertensive medications had a 5.9 mmHg reduction, and those with >4 grams of sodium intake per day had a 6.9 mmHg reduction. Increased potassium intake is also particularly efficacious in Black persons with as little as 20 meq resulting in a 7 mmHg SBP reduction.³ Therefore, potassium supplementation can be expected to have the largest effect for patients who are already identified and treated for hypertension, many of whom are likely to have a high sodium intake.

A dose response relationship between potassium and blood pressure lowering exists in observational studies, although not observed in the meta-analysis by Aburto et al. However, participants with <1.2 grams/day of potassium supplementation did have a statistically significant 4.9 mmHg (95% CI −7.6 to −2.2 mmHg) reduction in SBP, suggesting that even small amounts of potassium supplementation can lead to a significant blood pressure reductions.² Indeed, the recommendation for 4.7 grams of potassium per day is primarily based on the amount required to normalize blood pressure in a group of African American trial participants fed a high sodium diet.⁴ This trial also demonstrated a dose response relationship, which further supports the efficacy of even low amounts of potassium supplementation.

The majority of trials investigating increased potassium intake have done so using pill based supplementation, but studies using dietary supplementation have shown similar, if not higher, reductions in blood pressure.² Moreover, dietary potassium is generally found in low sodium foods such as fruits and vegetables and an increased intake of whole foods that naturally contain potassium can also facilitate a reduction in an individual’s sodium to potassium ratio. An increased consumption of foods naturally rich in potassium and other nutrients is also a cornerstone of the Dietary Approaches to Stop Hypertension (DASH) diet, which is endorsed by all major hypertension guidelines. The DASH diet can significantly lower an individual’s blood pressure through a combination of lower sodium intake and increased potassium intake. It is also rich in fiber and other nutrients such as magnesium, which in a recent meta-analysis of randomized trials demonstrated a 2 mmHg reduction in SBP with a median dose of 368 mg/day.⁵ However, there are varying levels of potassium within different foods and the recommendation to target specific potassium rich foods such as bananas, navy beans, raisins, et cetera may be helpful to achieve maximal blood pressure lowering.

Since most individuals in the US consume well below the recommended intake of 5 fruits and vegetables per day, an increased consumption of fruits and vegetables, with a concordant decrease in processed foods, may also result in weight loss, which is independently associated with incident hypertension and blood pressure reduction. Potassium supplementation through fruits and vegetables also has the additional benefits of reducing the risk of diabetes, certain cancers, and other adverse outcomes. Accordingly, in the correctly identified population, there may be an under-recognized blood pressure lowering benefit in recommending the increased consumption of potassium-rich foods.

Increased potassium intake has long been demonstrated to reduce blood pressure with studies dating from as early as the 1920’s. However, previous guideline committees have shied away from its recommendation given the increased risk of hyperkalemia. Caution should be taken in recommending potassium supplementation for patients at risk for hyperkalemia including those with a serum potassium >4.5 mmol/L, chronic kidney disease (CKD), and those taking medications that increase serum potassium, in particular angiotensin converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone receptor antagonists. However, the mean US daily potassium intake of 2.6 grams is well below the recommendation of ≥4.7 grams and potassium rich foods such as bananas contain only about 585 mg per serving. This makes it difficult to ingest sufficient quantities from a dietary source to result in a clinically actionable increase in serum potassium for patients with normal kidney function.

Therefore, while no specific recommendation on the amount of potassium supplementation is provided within the CHEP guidelines, it would be reasonable to recommend the addition of at least one to two servings of fruits and vegetables rich in potassium (approximately 390–1170 mg) as patients with this level of potassium supplementation have demonstrated significant reductions in blood pressure.^2,3 A stronger recommendation of 2–3 additional servings per day would be reasonable for patients who are Black (in whom hypertension is more prevalent and potassium supplementation is particularly efficacious) while no more than 1 additional serving would be advisable in patients at risk for hyperkalemia, such as those with CKD.^3,4

These most recent CHEP guidelines represent an important step forward in blood pressure treatment. While this blood pressure treatment recommendation has not captured the spotlight in the CHEP guidelines, its impact on patient care should not be underestimated and it may provide an impetus for other guideline committees to consider the recommendation of increased potassium intake. An increase in dietary potassium intake through the consumption of fruits and vegetables, in the correctly identified demographic of patients with hypertension and high sodium intake may help patients achieve their blood pressure goals with efficacy similar to that of an additional pharmacologic agent.