5 Reasons To Make Seaweed Part of Your Meals

You may only think of seaweed as that greenish-brown plant that washes up on the beach. But seaweed has been a staple of many Asian meals — especially in Japan, China and Korea — for centuries.

So, is seaweed good for you?

Today, seaweed is gaining in popularity in the United States and other Western countries — and seaweed benefits include improving your gut health and lowering your risk of certain diseases.

“Most Americans associate seaweed with sushi,” says registered dietitian Julia Zumpano, RD, LD. “But it’s a very versatile plant that’s chock-full of minerals and nutrients.”

What is seaweed?

Seaweed (also called macroalgae) refers to a variety of ocean plants, including sea moss and spirulina. There are more than 145 edible seaweed species.

“You can have seaweed fresh, cooked, dried or as a supplement,” says Zumpano.

The most popular seaweed types in the U.S. include:

• Brown seaweed (kelp): A common ingredient in the stock for miso soup
• Green seaweed (sea lettuce): Commonly found in seaweed supplements and used in thickeners for sauces and salad dressings
• Red seaweed (nori): A wrapper for sushi

What are the health benefits of seaweed?

Seaweed’s natural plant chemicals (phytochemicals) and low calories and fat make it a nutritional powerhouse or superfood.

Zumpano shares five potential benefits of seaweed.

1. Lowers your risk of certain diseases

Seaweed has several nutrients that help prevent disease, including polyphenols and omega-3 fatty acids. It’s also high in carotenoids like beta-carotene and lutein.

“These nutrients make seaweed a potential nutraceutical, meaning it could have medicinal benefits,” says Zumpano.

Some studies suggest that polyphenols in seaweed act as antioxidants, helping protect against the damaging effects of free radicals. Cell damage from free radicals can lead to cancer, autoimmune disease, Alzheimer’s disease and other life-changing conditions.

2. Protects your heart

A large prospective study from Japan found that people who ate a lot of fish, seaweed, mushrooms and other vegetables were less likely to get heart disease or die from a heart problem.

This plant-and-fish-based eating differs from Western diets, which tend to be higher in red meat, ultra-processed foods and sodium. These foods increase heart disease risk.

“Seaweed alone isn’t heart protective, but it is when consumed regularly in combination with fish and other vegetables,” notes Zumpano.

3. Builds muscles and tissues

Seaweed is a complete protein, containing the nine essential amino acids your body needs to build muscle, repair tissue and transport nutrients around your body.

But most people (even those who follow plant-based diets) don’t usually eat enough seaweed for it to be considered a major source of dietary protein.

4. Improves gut health

Seaweed is rich in polysaccharides. This carbohydrate acts like dietary fiber and serves as a food source (prebiotic) for healthy bacteria in your gut. Seaweed has other healthy fibers, too, including cellulose.

“This insoluble fiber binds to water in your digestive tract,” explains Zumpano. “Fiber slows digestion, so you feel full longer and are less likely to overeat.”

A high-fiber eating plan also:

• Lowers your risk of constipation
• Keeps blood sugar levels stable
• Lowers cholesterol

5. Provides a low-calorie, low-fat source of nutrients

The nutritional benefits of seaweed depend on the type (brown, green or red) and whether it’s raw, cooked or dried.

Overall, seaweed has 10 times the minerals of many vegetables. Seaweed is a good source of:

• Calcium
• Iodine
• Iron
• Vitamin B12
• Vitamin C
• Vitamin E
• Vitamin K
• Zinc

How much seaweed should you eat?

Eating seaweed is generally safe. But there are some potential health risks if you eat too much or have certain health conditions.

Diarrhea

Seaweed can act like a laxative when you eat too much, causing you to run to the bathroom. This problem is more common in people with digestive issues like irritable bowel syndrome (IBS).

Excess iodine and thyroid problems

Seaweed, especially brown seaweed or kombu, contains a high amount of iodine. Your body needs this mineral for healthy thyroid function. But too much iodine can lower your body’s natural production of thyroid hormones, causing an underactive thyroid (hypothyroidism).

“Children and adults with any thyroid issue should watch how much extra iodine they consume,” warns Zumpano.

Metal toxicity

Depending on where your seaweed comes from — an ocean, lake or river — it may have high levels of dangerous heavy metals. Seaweed absorbs metals like arsenic, cadmium, lead and mercury from contaminated water.

Most seaweed sold in the U.S. comes from seaweed farms in the ocean or saltwater tank farms. And studies indicate that edible seaweed tends to have low levels of toxic metals. Taking in a small amount of metals from seaweed dishes or supplements shouldn’t pose a health risk.

But metals can build up in your body if you eat seaweed every day. This increases the risk of organ damage, cancer, heart problems and heavy metal poisoning (toxicity).

Because of this contamination risk, it may be worth buying organic seaweed, says Zumpano.

Vitamin K and blood clots

Vitamin K in seaweed could be a problem if you take blood-thinning medications to prevent blood clots.

“Vitamin K is important for blood clotting,” says Zumpano. “But it can make blood-thinning medications less effective.”

Bottom line?

For most people, seaweed is a healthy way to add nutrients and variety to dishes. Not sure what to make? Try this delicious garden veggie omelet made with seaweed to get started!