Not Getting Enough Potassium? It May Be Affecting Your Blood Pressure

Potassium is an important mineral that you get from the food you eat. It’s an electrolyte that plays a key role in muscle and nerve health — along with other minerals like sodium, calcium, and magnesium. 

The heart and blood vessels are especially sensitive to potassium. When your potassium levels are low, your blood pressure may rise. But does this mean that getting extra potassium can help lower blood pressure? 

Here’s a closer look at how potassium can affect your blood pressure — along with what foods are high in potassium and when supplements might be helpful.

Does potassium lower blood pressure?

Potassium can help lower your blood pressure in a couple different ways. First, it helps the blood vessels to relax. If your potassium level is low, then your blood vessels can tighten, or constrict. This can cause your blood pressure to run higher. 

Potassium also helps to balance the effect of sodium on blood vessels. Sodium (found in salt) tends to raise blood pressure, while potassium brings it down. The two minerals also work as a team. If your diet includes a good amount of potassium, it can help your kidneys eliminate excess sodium. Likewise, cutting back on salt can also help your potassium levels.

For most people, the impact of potassium on blood pressure is small. But it’s still important. 

What are the benefits of getting more potassium?

When you eat foods that are high in potassium, they can can help: 

• Reduce the effect of salt on blood pressure

• Relax the blood vessels

• Provide fiber, vitamins, antioxidants, and other important nutrients

• Protect your heart and brain health

What foods are high in potassium?

Most people can easily get potassium from their diet. Common potassium-rich foods include:

• Avocados

• Baked potatoes and sweet potatoes

• Raisins and dates

• Bananas

• Spinach and most other greens

• Beans and lentils

• Yogurt and milk

• Mushrooms

• Salmon, tuna, and other fish

• Oranges and other citrus fruits

• Tomatoes

How do you know if you need more potassium?

It may be difficult to tell if you need more potassium, especially if your potassium level is only a little low. Symptoms are more likely with very low levels or if your levels drop quickly. 

Symptoms of low potassium include:

• Muscle aches

• Heart palpitations

• Tingling or numbness

• Fatigue

• Constipation

The only way to be certain of your potassium level is to get your blood tested. Potassium checks are usually included in routine blood work. 

How much potassium do you need to lower high blood pressure?

The amount of potassium you need to lower high blood pressure is going to vary from person to person.

In general, each day you need the following amounts of potassium:

• 3,400 mg for adult men

• 2,600 mg for adult women

Most people get enough potassium from their diet. But if you have low potassium levels, you may need higher amounts to keep your potassium levels within a normal range. More on this in the next section.

When should you take a potassium supplement for blood pressure?

If you have a low blood level of potassium, you may need a supplement. Some things that might cause you to need a supplement include:

• Certain medications — like diuretics (water pills), laxatives, and insulin 

• Diarrhea or vomiting

• Excessive sweating

• Eating disorders or restrictive diets

In general, it’s best to get a prescription for a potassium supplement from your healthcare team rather than take over-the-counter (OTC) supplements. This is for several reasons:

• They can recommend the right dose based on what your body needs.

• Prescription supplements can provide a much higher dose than OTC supplements — if that’s what you need.

• Your potassium blood level should be monitored when you take potassium supplements — especially since high potassium levels can be very dangerous.

If you’re already following a low-salt diet, a potassium supplement probably won’t make your blood pressure lower. Potassium supplements aren’t usually a substitute for blood pressure medication. It’s also important to note that if you start a potassium supplement, it may take several weeks for it to affect your blood pressure.

What are the risks of taking potassium supplements?

The kidneys are responsible for keeping your potassium levels normal. So, if you have kidney disease, potassium supplements can be dangerous. Some medications can also affect how the kidneys handle potassium. That’s one more reason why it’s important to talk to your primary care provider and get your blood tested before starting a supplement. 

If your potassium levels get too high, it can cause serious heart rhythm problems. In the worst cases, this can be fatal.

Common side effects of potassium supplements include:

• Nausea and vomiting

• Abdominal pain

• Diarrhea

• Throat irritation 

Is it OK to take potassium supplements with blood pressure medications?

Potassium can interact with a variety of other blood pressure and heart medications. These include:

• Diuretics (water pills): Some of these can lower potassium levels. Other diuretics will raise your potassium. 

• ACE inhibitors and ARBs: If you take an ACE inhibitor or ARB (angiotensin II receptor blocker), adding a potassium supplement could make your potassium level very high. 

That doesn’t mean you can’t take potassium with these medications. It’ll depend on what other medications you take and what other conditions you have. Your healthcare team can help you figure out how much you need to keep your potassium level in balance.

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Written by:

Sarah A. Samaan, MD

Sarah Samaan, MD, FACC, FACP, FASE is a board-certified cardiologist who practiced clinical cardiology for nearly 30 years. She is a member of the American College of Cardiology and the American College of Physicians, among others.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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