Nutrition Diet: Which greens are low in potassium?

November 8, 2025 •

4 min read

According to research published by the National Kidney Foundation, many leafy greens are surprisingly low in potassium and safe for restricted diets, depending on how they are prepared. This makes it possible to determine which greens are low in potassium without sacrificing flavor or nutrition.

Quick Summary

A low-potassium diet can be managed by choosing the right greens. The best choices include certain varieties of raw lettuce, cabbage, and kale. Some vegetables, like spinach, can be low in potassium when raw but become high after cooking due to concentration. Proper cooking and portion control are key to managing potassium intake effectively.

Key Points

Choose wisely: Opt for naturally low-potassium greens such as lettuce, cabbage, watercress, and arugula for daily consumption.
Watch your spinach: Be aware that raw spinach is low in potassium, but the mineral becomes concentrated when cooked, significantly increasing its potassium level.
Use leaching: Employ cooking methods like boiling in plenty of water to reduce the potassium content in greens and other high-potassium vegetables.
Discard cooking water: Always discard the water used for boiling or leaching, as it will contain the potassium that was removed from the vegetables.
Control portions: While low-potassium greens are safe, large portions of any food can increase potassium intake. Stick to recommended serving sizes.
Avoid salt substitutes: Many salt substitutes are high in potassium chloride and should be avoided on a low-potassium diet.
Consult a professional: For personalized dietary advice, especially if you have a health condition like kidney disease, consult a doctor or a registered dietitian.

Understanding Potassium and Your Diet

Potassium is an essential mineral that plays a vital role in nerve function, muscle contraction, and maintaining a healthy fluid balance in the body. For most healthy individuals, a diet rich in fruits and vegetables—many of which are high in potassium—is recommended. However, for people with kidney disease or other conditions that impair the body's ability to excrete potassium, too much can lead to a condition called hyperkalemia, which can be dangerous. A low-potassium diet is often prescribed in these cases to help manage blood levels. This can be particularly challenging when it comes to vegetables, as many are known for their high potassium content.

The Importance of Preparation: Raw vs. Cooked Greens

When managing potassium intake from leafy greens, the method of preparation can be just as important as the type of green. Potassium is a water-soluble mineral, meaning it can leach out of food when cooked in water. However, this effect varies and does not apply to all greens in the same way. The most notable example is spinach.

Raw spinach is considered a low-potassium green, with approximately 84 mg per half-cup serving. However, when spinach is cooked, the leaves wilt and shrink significantly, concentrating the mineral content. A half-cup of boiled spinach can contain as much as 420 mg of potassium, making it a high-potassium food. This highlights the need to be mindful of both the green you choose and how you prepare it.

Which Greens are Low in Potassium?

For those on a potassium-restricted diet, incorporating a variety of greens is still possible and recommended for nutritional diversity. Here is a list of greens and similar vegetables that are generally low in potassium:

Lettuce: All varieties, including iceberg, romaine, and leaf lettuce, are excellent low-potassium choices. A single cup of lettuce contains about 80 mg of potassium.
Cabbage: Green and red cabbage are low in potassium, both raw and cooked. Raw cabbage has about 86 mg of potassium per half-cup serving.
Raw Kale: While kale is a powerhouse of nutrients, its potassium content is manageable. Raw kale is lower in potassium than cooked spinach, though a half-cup serving is still important to adhere to. Boiled kale is considered a medium-potassium food.
Arugula: For those who prefer a peppery kick in their salad, arugula is another great option. It is naturally low in potassium.
Watercress: This nutrient-dense, peppery green contains only about 56 mg of potassium per half-cup.
Alfalfa Sprouts: Tiny and tender, alfalfa sprouts are very low in potassium, with just 13 mg per half-cup.
Bok Choy: Raw or lightly boiled, bok choy is a good low-potassium option. Its potassium level is lower when boiled.

Comparing Greens: High vs. Low Potassium


Green	Serving (1/2 cup)	Potassium Content	Notes
Raw Spinach	Chopped	Approx. 84 mg	Considered low-potassium in this form.
Boiled Spinach	Boiled	Approx. 420 mg	Potassium is concentrated, making it high.
Raw Kale	Chopped	Approx. 150-210 mg	Manageable, considered low to medium.
Boiled Kale	Boiled	Approx. 150-210 mg	Remains in the low to medium range.
Raw Lettuce	1 cup	Approx. 80 mg	A very low-potassium choice for salads.
Raw Cabbage	Chopped	Approx. 86 mg	Suitable for regular consumption.
Swiss Chard	Boiled	Approx. 480 mg	High potassium content, should be limited.
Beet Greens	Boiled	Approx. 1309 mg	Extremely high potassium; avoid on restricted diets.

Practical Tips for Managing Potassium from Greens

For those who enjoy greens that are naturally higher in potassium, like spinach, or for preparing other vegetables, there are methods to help reduce their potassium content. Potassium is water-soluble, and proper cooking can help remove a significant portion of it. This process is known as leaching.

How to Leach Vegetables

Peel and Chop: Begin by peeling vegetables (if applicable) and chopping them into small, thin pieces. This increases the surface area for the potassium to leach out.
Soak: Place the chopped vegetables in a large pot and soak them in a generous amount of warm, unsalted water for at least two hours.
Rinse: After soaking, rinse the vegetables thoroughly under warm water.
Boil: Cook the vegetables in a new pot with a large volume of fresh, unsalted water. Use about 10 times more water than vegetables for optimal leaching. Boil for several minutes until cooked.
Discard Water: Always discard the cooking water, as this is where the leached potassium is contained. Do not use it for soups, gravies, or other recipes.

Low-Potassium Salad and Recipe Ideas

Salad: Start with a base of iceberg, romaine, or green leaf lettuce. Add texture and flavor with other low-potassium vegetables like cucumber, bell peppers, and carrots. A vinaigrette dressing is a great choice.
Sautéed Greens: Sauté raw cabbage or raw kale with garlic and onions. Season with herbs and spices instead of salt substitutes, which are often high in potassium.
Wraps and Sandwiches: Use large, crisp lettuce leaves as a low-potassium alternative to traditional wraps or bread.

Conclusion

A low-potassium diet doesn't mean you have to give up healthy, nutrient-rich greens. By understanding which greens are naturally low in potassium, such as lettuce, cabbage, and watercress, and by learning how to properly prepare others, like spinach, you can maintain a balanced and flavorful diet. For those with kidney disease, consulting with a doctor or registered dietitian is the best way to develop a personalized meal plan. With a little knowledge and preparation, you can confidently include a wide variety of greens in your meals while effectively managing your potassium levels.

For more information on dietary management for kidney health, consult resources from organizations like the National Kidney Foundation.

Frequently Asked Questions

The safest leafy greens for a low-potassium diet include raw lettuce (all varieties), green and red cabbage, alfalfa sprouts, and watercress, as they are naturally low in potassium.

You can eat raw spinach in moderation, but you should avoid cooked spinach. Cooking concentrates the potassium, making a half-cup serving go from low to high potassium.

Yes, because potassium is water-soluble, cooking vegetables by boiling them in a large amount of water can help leach some of the potassium out.

To leach vegetables, first peel and chop them into thin pieces. Soak them in warm, unsalted water for at least two hours. Then, rinse the vegetables and cook them in fresh water, discarding all the water afterward.

Raw kale is considered a low to medium potassium green. Boiling kale does not concentrate its potassium to the same degree as spinach, keeping it in a manageable range for most restricted diets, but portion size is still important.

Some of the highest potassium greens include cooked spinach, Swiss chard, and beet greens. These should be limited or avoided on a potassium-restricted diet.

Yes, herbs and spices are an excellent way to add flavor to your low-potassium greens. Use them instead of salt substitutes, which often contain high amounts of potassium chloride.