What seafood can you eat on a low potassium diet?

January 11, 2026 •

4 min read

According to the National Institutes of Health, a higher intake of dietary potassium is associated with lower blood pressure, but for individuals with kidney dysfunction, a low-potassium diet is necessary to prevent dangerous hyperkalemia. While many meats and fish contain potassium, specific seafood varieties can be safely incorporated into a renal diet. This guide provides a detailed look at selecting and preparing low-potassium seafood to help manage your dietary needs effectively.

Quick Summary

This guide outlines safe seafood options for a low potassium diet, detailing specific choices like clams, shrimp, and cod, and offering cooking tips to reduce potassium levels. It also distinguishes between safe choices and those to moderate or avoid, such as processed items.

Key Points

Choose Low-Potassium Seafood: Opt for seafood like clams, shrimp, flounder, and canned light tuna packed in water, as these options are naturally lower in potassium.
Practice Portion Control: For moderate-potassium seafood like salmon and lobster, adhere strictly to recommended serving sizes to stay within your daily potassium limits.
Prepare Seafood Properly: Employ boiling techniques for some foods, and discard the cooking water to reduce potassium content; avoid steaming or microwaving for this purpose.
Avoid Processed Options: Steer clear of processed seafood, deli meats, and pre-packaged fish with sauces, as they often contain high levels of sodium and hidden phosphorus additives.
Consult a Registered Dietitian: For a personalized and safe dietary plan, always seek professional guidance from a healthcare provider, especially a registered dietitian specializing in renal health.
Check Labels for Additives: When buying canned or pre-packaged seafood, always read the nutrition labels to ensure no phosphorus or high potassium additives have been used.

A low-potassium diet is often recommended for individuals with chronic kidney disease (CKD) or other conditions that affect the body's ability to regulate potassium levels. While meat, poultry, and seafood are all sources of potassium, the amount varies significantly by type. Knowing which seafood to choose and how to prepare it can make a crucial difference in managing your diet without sacrificing flavor or nutrition.

Safe Seafood Choices for Low Potassium Diets

Not all seafood is created equal when it comes to potassium content. Some varieties are naturally lower, making them excellent choices for those on a restricted diet. The following options contain less than 200 mg of potassium per 3.5-ounce (100g) serving:

Clams: With just 58 mg of potassium per 100g, clams are one of the lowest potassium seafood choices available and can be a delicious addition to your meals.
Shrimp: A 100g serving of cooked shrimp contains approximately 101 mg of potassium, making it another fantastic low-potassium protein source.
Canned Light Tuna (in water): Canned light tuna packed in water contains about 176 mg of potassium per 100g serving. It's crucial to select low-sodium varieties and to rinse the tuna to reduce sodium content by up to 50%.
Flounder or Sole: Cooked flounder or sole offers about 167-197 mg of potassium per 100g. These delicate white fish fillets are versatile and low in fat.
Catfish: This is another low-potassium option, especially fresh fillets.
Cod: Cooked Atlantic cod has about 207 mg per 100g, placing it slightly over the 200mg threshold but often considered manageable in portion-controlled amounts. Consult a dietitian for proper serving sizes.

Seafood to Eat in Moderation

Some fish, while nutritious, have a higher potassium content. These can still be incorporated into a balanced renal diet with careful portion control, as advised by your healthcare provider. Examples include:

Salmon: While higher in potassium and phosphorus, salmon is rich in beneficial omega-3 fatty acids. DaVita suggests combining it with lower-potassium sides and using phosphorus binders if necessary. A 3-ounce portion of smoked Chinook salmon has 149 mg, while cooked salmon can have around 439 mg per 100g.
Lobster: This shellfish contains about 247 mg of potassium per 100g.
Oysters: Offering 193 mg of potassium per 100g, oysters are on the cusp of the low-potassium category and may require moderate consumption based on your specific dietary plan.

A Note on Processed and Canned Seafood

When choosing seafood, especially canned products, vigilance is key. Many processed and canned items may contain hidden potassium and phosphorus additives.

Canned Tuna: Always read labels for added phosphorus. For canned tuna, choose low-sodium versions and rinse it for a minute to reduce sodium content.
Processed Seafood: Avoid deli meats, breaded and fried fish, and fish covered in heavy sauces, as these can be high in both potassium and sodium.

Preparation Methods to Reduce Potassium

Cooking can significantly impact the potassium content of foods, including seafood. Certain methods can help reduce mineral levels, while others should be avoided.

How Cooking Affects Potassium Levels

Boiling and Discarding Water: For higher-potassium items, boiling in a large amount of water and then discarding that water can help leach out some of the potassium. For example, studies on other high-potassium foods have shown this technique effectively reduces potassium content.
Soaking: Soaking food in hot water can also reduce potassium levels.
Steaming and Microwaving: Avoid these methods, as they use minimal water and do not allow the potassium to leach out, leaving the mineral content largely intact.

Low Potassium Seafood Comparison


Seafood Type	Potassium (mg per 100g/3.5 oz serving)	Considerations
Clams	~58 mg	Very low potassium; good choice
Shrimp	~101 mg	Low potassium; excellent protein source
Canned Light Tuna (in water)	~176 mg	Low potassium; rinse to lower sodium; check for additives
Flounder/Sole	~167-197 mg	Low potassium; versatile white fish
Oysters	~193 mg	Moderate potassium; suitable for some plans
Atlantic Cod (cooked)	~207 mg	Borderline low; watch portion sizes carefully

Consulting a Professional

Following a low-potassium diet requires careful attention to serving sizes and food preparation. It is always recommended to consult a registered dietitian for personalized guidance on managing your dietary intake. They can help you create a meal plan that works for you, ensuring you meet your nutritional needs while managing your health condition. The American Kidney Fund offers valuable resources for individuals managing their diet.

Conclusion

While many people believe all seafood is high in potassium, several varieties are safe and nutritious choices for those on a restricted diet. By opting for low-potassium options like clams, shrimp, and water-packed tuna, and utilizing proper cooking techniques, you can enjoy the benefits of seafood while managing your potassium intake effectively. Always remember to check labels for additives in processed items and consult a healthcare professional for personalized dietary advice.

Frequently Asked Questions

Yes, canned light tuna in water is a safe option for a low potassium diet. Be sure to choose a low-sodium version and rinse it to reduce sodium content. Always check the label for added phosphorus.

Clams are one of the lowest seafood options in potassium, with only 58 mg per 100-gram serving. Shrimp and flounder are also very low in potassium.

No, shrimp is not high in potassium. A 100-gram serving contains just 101 mg of potassium, making it a good protein choice for a low-potassium diet.

For fish that may be slightly higher in potassium, some of the mineral can be removed by boiling it in a large amount of water and then discarding the water. Soaking can also be effective.

A low-potassium diet is necessary for individuals with impaired kidney function because their bodies cannot adequately remove excess potassium through urine. A buildup of potassium (hyperkalemia) can be dangerous.

Salmon is higher in potassium than some other fish but can be included in moderation with proper portion control. A registered dietitian can provide specific guidance.

It is important to check labels on canned seafood to avoid products with added phosphorus and potassium-based additives, which can increase mineral intake.