Vitamin Sea: Unlocking The Healing Power Of Sea Vegetables For Optimal Health

We live on a planet covered by water. About 71 percent of the Earth’s surface is underwater and our climate, not to mention the health of all living species, is intimately connected to the ocean. (1) Half the oxygen we breathe is produced by sea vegetation, so why not look to the sea for health remedies that don’t exist on land? (2)

In my telehealth functional medicine clinic, we are always looking to support our health through nutrient-dense, bioavailable foods. Sea vegetables are often overlooked in Western diets but are some of the most powerful superfoods we can consume. From kelp and nori to dulse and spirulina, sea vegetables have been used for centuries across cultures for their therapeutic benefits. Now, modern research is starting to validate what these traditions have long understood — that the ocean holds an abundance of healing superfoods that can support everything from thyroid health to detoxification. Let’s take a look at the different types of edible seaweeds and sea vegetables, their benefits, and how you can start incorporating them into your daily routine.

What are sea vegetables?

Sea vegetables include a variety of marine plants and algae that grow in the ocean, offering a range of bioactive compounds. Unlike land-based vegetables, since sea vegetables thrive in saltwater environments, they end up absorbing numerous minerals directly from the sea. This results in higher concentrations of unique and beneficial minerals like iodine and other trace elements that are not found as abundantly in other plant-based foods.

Historically, sea vegetables have been considered an exotic delicacy in island cultures from Asia to New Zealand to Ireland, and are typically harvested from boats directly from the ocean or are harvested by hand on rocky shorelines.

Types of sea vegetables

Dulse

Dulse is a type of red algae that grows on the northern coasts of the Pacific and Atlantic oceans. It’s commonly used in Ireland and Iceland to cook with and snack on, but we aren’t so familiar with it here. Let’s change that! In addition to its iodine content, it’s an excellent source of protein.

How to use: Purchase dulse in powdered form to use just like a spice – it can flavor all your savory dishes, from soup to pizza. You can also add a pinch or two to your morning smoothie for a first-thing iodine boost.

Kombu

This edible kelp is cultivated in Japan and Korea. It is the single greatest source of iodine out of all the sea vegetables and a base for dashi in miso soup, so definitely audition it for a role in your regular diet.

How to use: Since it’s pretty chewy, it’s not great to eat on its own, but it can add a deep briny flavor to soups and is a common ingredient in Japanese soup stock and broth. Typically you buy chunks of it, cutting off and soaking the pieces to rehydrate them before use. You can also buy it powdered to add to smoothies, soups, or your other culinary creations.

Kelp

Kelp is a specific type of Kombu and its iodine levels are sky-high, with some varieties having up to 2,984 micrograms per 1 gram serving; giving it some of the highest iodine content of any sea vegetable. (3) It’s also a rich source of magnesium, and since many of us are also magnesium-deficient, kelp can solve two problems in one delicious dose.

How to use: Kelp (wakame in particular) is often used in miso soup. Dried kelp flakes are crunchy, salty little pieces of yum. Add them to salads for crunch, soups for flavor, or to garnish any savory dish that needs something extra special. You might also try kelp noodles, a yummy and easy-to-eat form of this sea vegetable.

Spirulina + Blue-Green Algae

Spirulina and other blue-green algae live in lakes – both fresh and saltwater – throughout the world. Blue-green algae was a traditional remedy and highly revered food in ancient civilizations, especially in Mexico and Africa. Today, both can be found powdered and pre-packaged at your local health food store for your convenience with all the health benefits. Spirulina is jam-packed with tons of benefits; it is made up of 55-75% protein and contains all essential amino acids (the ones your body can’t make and you need to get from food). Spirulina’s chlorophyll content makes it super detoxifying. (4)

How to use: Ever seen those beautiful blue smoothies and unicorn lattes? You can thank spirulina for the brilliant aquatic hues. No artificial dyes needed! Try mixing a teaspoon or two of blue-green algae into your own healthy elixirs, teas, and smoothies. I bet you can make something just as artistic and a whole lot healthier. Check out some of my favorite recipes here.

Nori

This type of seaweed is probably what you’re most familiar with, as it’s used to wrap sushi rolls. It is technically a red-green algae that is first dried and then pressed to form the sheets you are familiar with eating in your sushi rolls. Like other forms of seaweed it is high in valuable nutrients like iodine and other trace minerals.

How to use: Buy these nori sheets and make yourself some delicious sushi or wraps! Add in some of your favorite seafood, avocado, cucumber, and cauliflower rice, wrap it up and enjoy! Perfect for a quick snack or on-the-go lunch, these are great dipped in some coconut aminos.

Irish moss

Not actually a moss, this seaweed is another variety of red algae commonly found along the Atlantic coast of North America and Europe, and is commonly consumed in (how did you guess?) Ireland. It has a rubbery/leathery texture so it may seem inedible, but it is high not just in iodine but also in potassium, contains the natural thickener carrageenan, and makes a great thickening agent in cooking.

How to use: Best soaked in liquid, it can then be chopped up and added to soups or broths. The water left behind takes on a gel-like quality which is great for thickening foods like sauces or soup.

Arame

This is a species of brown algae kelp, similar to wakame, mostly found in Japan and commonly sold dried.

How to use: Milder and sweeter than many other sea vegetables, arame is a great additive to any food because you won’t necessarily taste it. Soak it in water and add it to anything, even baked goods.

Health benefits of sea vegetables

There’s a reason why sea vegetables are considered a superfood. Not only are sea vegetables a great source of vitamins and minerals including B vitamins, vitamin C, vitamin K, magnesium, and 18 different amino acids, they contain important nutrients that have been shown to support key areas of your health. (5) 

Supports thyroid health

Sea vegetables are also one of the most effective ways to get the ultra-important mineral iodine, which your body needs to manufacture your thyroid hormones. Spirulina, dulse, and Irish moss are great plant sources of iron, which is also important for the production of thyroid peroxidase – the enzyme used to make healthy thyroid hormones. (6)

Regulates blood sugar

Sea vegetables also contain anti-inflammatory compounds called fucans that have been shown to improve blood sugar balance in type-2 diabetics. (7)

Enhances detoxification 

Sea vegetables are rich in both B vitamins and chlorophyll, which are much-needed for methylation and opening up your body’s detox pathways.

A note on iodine supplements versus sea vegetables

Maybe despite my glowing recommendations, the idea of eating seaweeds still turns you off. You may be thinking, “Can’t I just take an iodine supplement?” In addition to missing out on all of the other important nutrients and the synergistic magic of real food you would get from sea vegetables, iodine pills are not a good option for people with thyroid problems. This is very important to understand because health professionals often say “take iodine” for a natural solution to thyroid problems, but iodine supplements could actually trigger an autoimmune response toward the thyroid. While you do need iodine for thyroid hormone production, several studies have found that increased iodine intake is associated with Hashimoto’s disease. (8)

Research has also found that an increase in thyroid antibodies is associated with iodine supplementation. (9) This is why I much prefer getting a balanced source of iodine with all of the other uber-important nutrients in its natural form: seaweed. For autoimmune thyroid cases, I also suggest limiting kelp in particular, because of its higher iodine content. Instead, try some of the other varieties for a milder dose of natural iodine. We are all different. Even with healthy foods, what works for one person may not be right for you.

Where can I buy sea vegetables?

As more people begin to appreciate the wonders of sea vegetables, demand will increase and so will availability. Thankfully, you can now find many of these sea vegetables at Whole Foods and can be easily purchased online from places like Amazon. Before buying, the one thing to remember is to look for reputable brands that source their products sustainably. If you are getting sea vegetables from a contaminated water source containing toxins or other chemicals, the sea vegetables will be contaminated as well. Thankfully, the U.S. Food and Drug Administration has very high standards for the commercial sea vegetables it imports.

Other types of oceanic superfoods

While sea vegetables are fantastic, we don’t want to overlook the abundance of other superfoods located in our oceans. These are a few of my favorites to consider incorporating into your diet. 

Pearl

Yes, actual pearl, the gift of oysters and a secret of Asian medicine for generations. Crushed to a fine powder for use in skin care products and dietary supplements, pearl is a glamorous beauty secret.

What it can do for you: Pearl is an oceanic adaptogen rich in calcium, magnesium, amino acids, and a variety of minerals. It has been used for its calming and mood-regulating effects as well as being a super beauty food for more radiant skin.

How to use: Pearl has a mild taste, so it goes great in just about everything. I specifically decided to formulate my supplement holi ( m a n e ) with Agent Nateur with pearl and marine collagen. These two oceanic superfoods work synergistically to support everything from your body’s own healthy collagen production to radiant hair, skin, and nails. It also goes great in smoothies, elixirs, and baked goods. 

LISTEN: Collagen Myths, Fertility, Glowing Skin, Regrowing Hair & Healing Endometriosis with Jena Covello

Marine Phytoplankton

This microalgae is considered the most important plant in the world because it provides earth with over 90 percent of its oxygen – more than all the forests in the world combined! But marine phytoplankton is not only an important source of oxygen; it’s a critical food source for ocean life and humans, too.

What it does for you: There are very few foods on this Earth that provide the raw materials for our bodies to make new cells and sustain the ones we have, but marine phytoplankton is one of them. It contains all nine amino acids that the body cannot make on its own, along with the essential omega fats; vitamins A, C, a variety of B vitamins; and trace minerals. (10) Think of it as the most pure and potent food possible for your cells.

How to use: Unless you’re going to wade around the ocean scooping up microalgae in bags of cheesecloth, the best way to get phytoplankton is through supplementation.

Sea Salt

Salt is actually a superfood – if it comes from our most pristine oceans. Nothing like conventional table salt, sea salt is mostly unprocessed and rich with minerals. Beautiful red Hawaiian sea salt comes from volcanic rock, Italian sea salt is harvested off the Mediterranean coast of Sicily, and the beautiful pink Himalayan sea salt so popular in health food stores these days is harvested from ancient seabeds, originally formed from marine fossil deposits over 250 million years ago.

What it does for you: These different salts contain a wide variety of minerals that aid in optimal immune, hormone, and electrolyte balance.

How to use: Use these superfood salts like you would use any salt – sprinkled on food for a fuller and more satisfying flavor. You can also simulate a dip in the sea by adding sea salt to your bath. Just pour two cups of one of these salts into your bath and soak up the healing properties straight through your skin. It may be a little pricey to do this, but it’s way cheaper than a trip to Hawaii!

READ MORE: A Functional Medicine Guide To the Healing Powers Of Sea Salt

Krill Oil

Krill are tiny crustaceans found in every ocean, and there are more of these little guys on the planet than any other creature! Imagine picking any species – even humans – and putting them all together on a scale. All the krill would weigh more!

What it does for you: Most of us are lacking healthy fats, specifically omega-3s, which contribute to health problems like depression, heart disease, arthritis, and inflammation. Krill oil is superior in many ways to conventional fish oil. It contains the powerful antioxidant astaxanthin, along with beneficial phospholipids phosphatidylcholine and phosphatidylserine that you need for optimal cellular, hormone, brain, and nerve health. (11) 

How to use: Krill oil is usually sold in capsules. Take them, like any supplement, according to package instructions. 

Wild-Caught Seafood

Fish caught straight out of the ocean (rather than raised on a fish farm) have high omega-3 fats. If you choose wild-caught salmon, sardines, rainbow trout, Atlantic mackerel, and shellfish like mussels and oysters – that are rated by the Environmental Working Group as having lower mercury levels and higher sustainability – you will get the most benefit. Avoid those with higher toxin levels, like king mackerel, marlin, orange roughy, shark, swordfish, and tilefish.

What it does for you: Similar to krill oil, wild-caught fish have the brain-, hormone-, heart-, and immune-supporting omega-3 fatty acids – but in delicious whole-food form, so they also include a wider variety of nutrients, minerals, and fats that can’t be encapsulated in a pill.

How to use: There are so many ways to enjoy fish, I couldn’t possibly list them all here. Personally, I am partial to fish tacos, with lettuce or cassava flour wraps to keep them grain-free.

Marine Collagen

Putting grass-fed collagen powder in lattes and coffee is definitely a health trend, but one lesser-known collagen option is marine collagen from wild-caught fish.

What it does for you: One of the cleanest, most bioavailable sources of protein, marine collagen is also a great way to support the growth and maintenance of healthy skin, hair, and joints. Rich in glycine, collagen is also great for supporting optimal gut and immune health.

How to use: Most marine collagen comes in powdered form, but it can be difficult to find a high-quality marine collagen supplement. That’s why I partnered with Agent Nateur to create holi ( m a n e). This exclusive supplement combines two powerhouse oceanic superfoods: marine collagen and pearl powder. This odorless and nearly tasteless blend is abundant in over 30 trace minerals and amino acids that support optimal hair, skin and nail health. The synergy of this nutrient-dense blend also supports the increase of two important antioxidants, glutathione and superoxide dismutase, both essential for cell vitality.

And if you really want a boost, combine holi ( m a n e ) with a scoop of holi ( r a d i a n c e ). Formulated with OptiMSM® — a high-grade antioxidant — and a phytoceramide complex, holi ( r a d i a n c e ) is designed to help amplify the effects of holi ( m a n e ) when taken together. 

Magnesium Salt

The ancient Zechstein Sea – a geological formation in Northern Europe – is rich with magnesium salt that has been protected, deep within the Sechstein Seabed at a depth of 2,000 meters beneath the Earth’s crust, from the toxins of our modern world. What a find!

What it does for you: Magnesium is responsible for the function of hundreds of different biochemical pathways in your body. Your hormones, brain, and heart depend on optimal magnesium levels, and most of us are deficient!

How to use: My favorite way to get this type of magnesium is from magnesium oil spray. This is one of the most bioavailable ways to ensure optimal magnesium levels. Spray it on, rub it in, and feel the serenity.

Bringing it all together

Adding sea vegetables into your diet may seem like a small shift, but one that can have a huge impact on your health. Want to add some seaweed to your diet but aren’t sure where to start? Try this delicious soup recipe, featuring several different varieties.

Sea Vegetable Whitefish Soup

Ingredients

• 2 pieces of kombu (roughly 3-inch squares)
• 1 cup lightly packed bonito flakes
• 4 cups water
• 2 to 6 ounces tilapia or cod fillets
• 1 lb. kelp noodles
• 2 tablespoons coconut aminos
• 1 tablespoon coconut water vinegar
• 4 cups loosely packed greens

Directions

Place kombu and bonito in water in a large pot and bring to a boil. Reduce heat and simmer for 10 minutes. Meanwhile, chop greens and cut the fish into 1 to 2-inch cubes. Cook kelp noodles as per directions on the package. Pour broth through a strainer lined with cheesecloth to remove bonito and kombu. Return the broth to the heat and add coconut aminos and coconut water vinegar. Add the fish and simmer for 5 minutes or until the fish is cooked through. If you are using tougher greens – such as bok choy, cabbage, snow peas, or kale – add them at the same time as the fish. For more tender greens – such as spinach, chard, or beet greens – add them after the fish is cooked and simmer one minute to wilt. Add the kelp noodles and simmer.

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Sources

• U.S. Geological Survey. (2019, November 13). How much water is there on Earth? https://www.usgs.gov/water-science-school/science/how-much-water-there-earth
• National Ocean Service. (2024, June 16). How much oxygen comes from the ocean? https://oceanservice.noaa.gov/facts/ocean-oxygen.html
• National Institutes of Health, Office of Dietary Supplements. (n.d.). Iodine: Fact sheet for health professionals. https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/
• Podgórska-Kryszczuk, I. (2024). Spirulina—An invaluable source of macro- and micronutrients with broad biological activity and application potential. Molecules, 29(22), 5387. https://doi.org/10.3390/molecules29225387
• Rajapakse, N., & Kim, S. K. (2011). Nutritional and digestive health benefits of seaweed. Advances in Food and Nutrition Research, 64, 17–28. https://doi.org/10.1016/B978-0-12-387669-0.00002-8
• Zimmermann, M. B., & Köhrle, J. (2002). The impact of iron and selenium deficiencies on iodine and thyroid metabolism: Biochemistry and relevance to public health. Thyroid, 12(10), 867–878. https://doi.org/10.1089/105072502761016494
• Kim, M. S., Kim, J. Y., Choi, W. H., & Lee, S. S. (2008). Effects of seaweed supplementation on blood glucose concentration, lipid profile, and antioxidant enzyme activities in patients with type 2 diabetes mellitus. Nutrition Research and Practice, 2(2), 62–67. https://doi.org/10.4162/nrp.2008.2.2.62
• Sun, X., Shan, Z., & Teng, W. (2014). Effects of increased iodine intake on thyroid disorders. Endocrinology and Metabolism, 29(3), 240–247. https://doi.org/10.3803/EnM.2014.29.3.240
• Boukis, M. A., Koutras, D. A., Souvatzoglou, A., Evangelopoulou, A., Vrontakis, M., & Moulopoulos, S. D. (1983). Thyroid hormone and immunological studies in endemic goiter. The Journal of Clinical Endocrinology & Metabolism, 57(4), 859–862. https://doi.org/10.1210/jcem-57-4-859
• Plankton for Health. (n.d.). What nutrients are in marine phytoplankton? https://planktonforhealth.co.uk/what-nutrients-are-in-marine-phytoplankton/
• Sarıyer, E. T., Baş, M., Çolak, H., Özkan Yenal, N., Unay Demirel, Ö., & Yüksel, M. (2024). Comparison of dietary supplementation with krill oil, fish oil, and astaxanthin on an experimental ethanol-induced gastric ulcer model: A biochemical and histological study. Nutrients, 16(20), 3426. https://doi.org/10.3390/nu16203426