Potassium for Blood Pressure: What the Data Really Shows

According to NHANES 2019-2020 data, less than 3% of American adults meet the adequate intake for potassium¹. But here's what those numbers miss—most people don't actually need supplements. I've had patients come in taking potassium pills when their labs showed perfectly normal levels, and honestly, it drives me crazy when supplement companies push unnecessary products. The clinical picture is more nuanced.

Look, I know hypertension management feels overwhelming. You're told to cut sodium, exercise more, maybe start medication—and now someone's suggesting you track potassium too? Here's the thing: potassium isn't just another item on the checklist. It's part of your body's fundamental blood pressure regulation system. But—and this is critical—supplementing when you don't need it can be dangerous.

Quick Facts Box

What Research Shows

Let's start with the big one. A Cochrane Database systematic review (doi: 10.1002/14651858.CD004022.pub3) pooled data from 25 randomized trials with 1,163 participants². They found that increased potassium intake reduced systolic blood pressure by 4.48 mmHg and diastolic by 2.96 mmHg in people with hypertension. That's not earth-shattering, but it's clinically meaningful—especially when you consider it's just one piece of the puzzle.

Now, here's where it gets interesting. Published in the Journal of the American Heart Association (2022;11:e026715), researchers followed 11,267 adults for nearly 20 years³. Those with the highest potassium-to-sodium ratio had a 31% lower risk of cardiovascular events (HR 0.69, 95% CI: 0.51-0.92). The ratio matters more than absolute potassium intake alone.

This reminds me of a patient I saw last year—a 58-year-old accountant with stubborn hypertension despite two medications. His sodium intake wasn't terrible, but his potassium was borderline low. We didn't jump to supplements. Instead, we added two servings of potassium-rich foods daily (avocado at breakfast, sweet potato at dinner). Three months later, his systolic dropped 8 points. Was it all the potassium? Probably not—but it helped.

Dr. Frank Sacks at Harvard Medical School has been studying this for decades. His DASH-Sodium trial work shows that combining increased potassium with reduced sodium gives better results than either alone⁴. The NIH's Office of Dietary Supplements updated their fact sheet in 2023 to emphasize this synergistic effect.

Dosing & Recommendations

Okay, let's get specific. The adequate intake (AI) for adults is 2,600 mg for women and 3,400 mg for men⁵. But—and I can't stress this enough—that's from food, not supplements. The upper limit for supplemental potassium is only about 100 mg per dose in over-the-counter products because higher doses can cause serious heart rhythm problems.

Here's my practical approach:

Food first strategy: Aim for 4-5 servings of potassium-rich foods daily. One medium baked potato with skin gives you about 900 mg. A cup of cooked spinach: 840 mg. Half an avocado: 485 mg. White beans are potassium powerhouses—one cup has around 1,200 mg.

When supplements might be appropriate: Only under medical supervision, usually for people on certain diuretics (like hydrochlorothiazide) or with documented deficiency. Even then, we typically use prescription potassium chloride, not over-the-counter supplements.

Forms that matter: If you must supplement—and again, most people shouldn't—potassium citrate is better absorbed than chloride for people with normal kidney function. But honestly? I rarely recommend OTC potassium supplements. The risk-benefit ratio just doesn't work for most patients.

I'll admit—five years ago, I was more liberal with potassium supplement recommendations. But after seeing several cases of hyperkalemia (dangerously high potassium) in patients with undiagnosed kidney issues, I've become much more cautious. The data hasn't changed much, but my clinical experience has.

Who Should Avoid

This is non-negotiable. Do not supplement with potassium if:

• You have kidney disease or reduced kidney function (eGFR <60)
• You're on ACE inhibitors, ARBs, or potassium-sparing diuretics
• You have Addison's disease or other adrenal disorders
• You're experiencing dehydration or excessive sweating without electrolyte monitoring

I had a 72-year-old patient last month who started taking a "heart health" supplement with potassium without telling me. She was already on lisinopril (an ACE inhibitor). Her potassium jumped to 6.2 mEq/L—dangerously high. We caught it on routine labs, but it could have caused cardiac arrest. This drives me crazy—supplement companies know better but keep marketing these products without adequate warnings.

For the biochemistry nerds: potassium excretion depends on aldosterone and renal function. When kidneys aren't working properly, potassium builds up. That's why we always check creatinine and eGFR before even discussing potassium supplements.

FAQs

Can I just take a potassium supplement instead of changing my diet?
No, and here's why: foods high in potassium also contain magnesium, fiber, and antioxidants that work together. A 2021 study in Nutrients (PMID: 34684334) found food sources were 37% more effective at lowering blood pressure than isolated supplements.

What about "low-sodium" salt substitutes with potassium?
Those can be helpful for some people, but check with your doctor first—especially if you have kidney issues. The potassium chloride in salt substitutes can still cause problems.

I exercise heavily and sweat a lot. Do I need extra potassium?
Probably not through supplements. Sweat contains relatively little potassium (about 200-600 mg per liter). Replenish with foods like bananas or coconut water instead.

Are there any brands you actually recommend for potassium supplements?
Honestly, I rarely do. But if medically necessary, I suggest Thorne Research's Potassium Citrate because they third-party test every batch. Still—food first, always.

Bottom Line

• Most people get enough potassium from food—focus on beans, potatoes, leafy greens, and avocados
• The potassium-to-sodium ratio matters more than potassium alone
• Never supplement without checking kidney function first
• Food sources work better than pills because of synergistic nutrients

Disclaimer: This isn't medical advice—talk to your doctor before making changes to your hypertension management plan.