Is Seaweed Good for You if You Have High Blood Pressure?

November 29, 2025 •

4 min read

According to the CDC, nearly half of adults in the United States have hypertension, or high blood pressure [1.1]. Exploring dietary changes is a primary strategy for managing this condition, but it raises a question for many: is seaweed good for you if you have high blood pressure?

Quick Summary

This article explains how the high potassium and beneficial peptides in seaweed can support healthy blood pressure, but also addresses concerns regarding high iodine and naturally-occurring sodium content. It outlines which varieties are best for a heart-healthy diet and offers practical advice for consumption.

Key Points

Rich in Potassium: Seaweed is a natural source of potassium, which helps balance sodium levels and supports lower blood pressure.
Natural ACE Inhibitors: Certain compounds in seaweed, like peptides, have been found to act as natural ACE inhibitors, helping to relax blood vessels.
Moderate Sodium Intake: Some seaweed contains sodium, so it's important to choose unprocessed varieties and check labels for added salt, especially if you have high blood pressure.
High Iodine Content: Be mindful of iodine levels, particularly in brown seaweeds like kelp and kombu, as excessive intake can affect thyroid health.
Use as a Salt Substitute: Using milled seaweed or flakes of dulse and sea spaghetti can reduce overall sodium intake while adding umami flavor.

The Sodium-Potassium Balance and Blood Pressure

High blood pressure is often influenced by an imbalance between sodium and potassium intake, with a high-sodium, low-potassium diet being a key culprit. While table salt is almost entirely sodium chloride, seaweed offers a naturally salty flavor from a broader range of minerals, including potassium. A higher potassium intake is crucial for balancing out excess sodium, as potassium helps the body excrete sodium through the urine, which in turn helps lower blood pressure. Some varieties of seaweed, such as Atlantic dulse, have a favorable potassium-to-sodium ratio.

Bioactive Peptides and ACE Inhibition

Beyond just minerals, scientific research has identified bioactive compounds in certain seaweeds that act as natural angiotensin-converting enzyme (ACE) inhibitors. ACE inhibitors work by blocking the production of a hormone that constricts blood vessels, allowing them to relax and widen. This action effectively lowers blood pressure. This mechanism is similar to that of some common hypertension medications, providing a potential dietary-based approach to blood pressure management. Several studies, particularly in Japanese populations, suggest that regular seaweed consumption is associated with lower blood pressure.

Concerns for People with High Blood Pressure

While the potential benefits are promising, there are important considerations for those with high blood pressure. The two main concerns are the variable sodium and very high iodine content found in different species of seaweed.

Sodium: Despite having a more favorable mineral profile than processed salts, some dried seaweed can still contain significant amounts of sodium. It is critical for individuals with high blood pressure to monitor total sodium intake, especially if they are already on a low-sodium diet. Seasoned, roasted, or processed seaweed snacks often have added salt, which can negate any potential benefits. Choosing plain, unprocessed seaweed is essential.
Iodine: Seaweed is one of the richest natural sources of iodine, a mineral vital for thyroid function. However, excessive iodine intake, particularly from certain types like brown seaweeds such as kombu and kelp, can negatively affect thyroid health and, in some cases, blood pressure. It is vital to consume seaweed in moderation, especially with these high-iodine varieties.

Choosing the Right Seaweed for Your Heart Health

Not all seaweed is created equal when it comes to blood pressure management. Selecting the right variety is key to maximizing benefits while minimizing risks.

Comparison of Seaweed Varieties for Heart Health


Seaweed Type	Potassium-to-Sodium Ratio	Iodine Content	Notes for Hypertension	Potential Use
Dulse	High (~1:3.8)	Moderate	Excellent ratio for balancing sodium; often has a smoky flavor.	Flakes for seasoning, sprinkling on salads or eggs.
Wakame	High	High	Clinical studies show potential benefits; use in moderation due to iodine.	Soups (miso), salads, stews.
Kombu	High	Very High	Use sparingly; often used as a flavor base (like in dashi broth) and then removed.	Natural bouillon base for stocks and soups.
Nori	Low to Moderate	Moderate	Widely available; common in sushi.	Sushi wraps, shredded on rice, roasted snacks (check for added salt).
Sea Spaghetti	High	Low	Good choice for regular consumption due to lower iodine and high potassium content.	Milled for salt replacement, pasta alternative.

How to Safely Incorporate Seaweed

Read Labels Carefully: Always check the nutrition facts for sodium content, especially for prepared or seasoned seaweed products. Look for unsalted or minimally processed options.
Start with Small Amounts: If you are new to seaweed, begin by adding small quantities to your diet, such as a sprinkle of flakes or a strip in a broth, to see how your body reacts.
Choose Lower-Iodine Varieties: Opt for dulse, nori, or sea spaghetti more frequently than high-iodine varieties like kombu or kelp. Consider consuming kelp less often or in very small portions.
Use as a Salt Substitute: Milled seaweed can be an effective way to naturally reduce your overall salt intake. The umami flavor can enhance dishes without needing excess sodium chloride.
Consult a Professional: It is advisable to consult a doctor or registered dietitian before making significant dietary changes, especially if you have high blood pressure or a thyroid condition.

Conclusion

For individuals with high blood pressure, seaweed can be a beneficial dietary addition when consumed thoughtfully. Its rich potassium content, alongside bioactive peptides with ACE-inhibiting properties, offers a natural way to support healthy blood pressure levels. However, it is vital to be aware of the high, though variable, sodium and iodine levels. By selecting unprocessed varieties like dulse and wakame, using them as a salt replacement, and practicing moderation, you can leverage seaweed’s benefits while minimizing risks. As always, personalized medical advice is crucial for managing hypertension, so discuss any dietary changes with your healthcare provider.

For further guidance, resources on low-sodium diets and nutrition are available through authoritative health organizations, such as the American Heart Association.

Frequently Asked Questions

Seaweed generally contains compounds like potassium and peptides that help lower blood pressure. However, some types can have high sodium content, so it is important to choose unprocessed varieties and consume them in moderation to avoid increasing blood pressure.

Dulse and sea spaghetti are good choices for blood pressure management due to their high potassium-to-sodium ratio and lower iodine content compared to kelp. Unsalted wakame is also beneficial, but should be consumed in moderation due to its higher iodine levels.

There is no one-size-fits-all recommendation, but consuming a small amount, such as a sprinkle of dried flakes or a strip in a broth, several times a week is generally safe. Very high-iodine seaweeds like kombu should be used sparingly. Consult a healthcare provider for personalized advice.

Yes, excessive iodine from regular, heavy consumption of high-iodine varieties like kombu can cause thyroid issues. Those with pre-existing thyroid conditions should be especially cautious and speak with their doctor.

Seaweed can be used as a part of a strategy to reduce salt intake, but it is not always a direct replacement for all cooking. It offers umami flavor and minerals that can complement or partially replace salt, but different species have varying flavors.

To manage blood pressure, use plain, unprocessed, or dried seaweed. Add flakes to salads, eggs, or steamed vegetables, or use a strip of kombu to make broth. Avoid highly processed, salty, or seasoned seaweed snacks.

While generally safe in food quantities, the high mineral and bioactive content could potentially interact with certain medications, especially those for the thyroid or blood pressure. Always consult your doctor before adding supplements or making major dietary changes, particularly if you are on medication.