Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
8 Jul

A Visual Guide to Sea Vegetables

About 160,000 years ago the human diet expanded to include seafood. Early humans became coastal dwellers at least that long ago, and ever since then we’ve been inextricably linked to the sea. The sea contains our most reliable source (when we aren’t dining on the brains of ruminants) of the all-important, long-chain omega-3 fatty acids. And then there’s the edible sea vegetation. I’ve written briefly about it before, but edible seaweed seems to be lacking from most folks’ diets, even those eating an otherwise complete Primal diet. For those in Western countries, the only seaweed they’ll happen across on a regular basis comes stuffed with rice and raw fish. It’s not a modern staple, unless you’re in Asia, and it simply isn’t on most people’s radars. It should be, though.

Pretty much every culture with coastal access throughout history made culinary use of sea vegetation. The Japanese and other Asian countries are famous for their seaweed consumption, but even the Vikings and Celts would chew on dried dulse for sustenance (and the red algae even figures into some of the old Norse epic sagas). Hawaiians and Polynesians cultivated kelp farms. Plato famously opined the “sea cures all evils,” and the ancient Greeks regularly ate edible seaweed. Any food with such a wide-ranging history of use across various cultures and time periods piques my interest.

The sea is an especially potent source of minerals. It’s an entirely different story with soil, which most experts agree is being rapidly depleted of mineral content by intensive over farming. And since the plants we eat are only as mineral-rich as the soil in which they grow, most commercial vegetation that ends up on our plates isn’t nearly as nutritious as the stuff your grandparents ate, let alone what Grok ate. Buying from smaller farms can mitigate the deficiencies to a certain extent, since those guys are generally more mindful of soil quality and replenishment (rather than just trying to produce the biggest, most durable fruits and vegetables in the shortest amount of time, nutrition and taste be damned), but incorporating sea vegetables into your diet is an affordable, delicious, surefire way to obtain missing mineral content.

Whereas terrestrial vegetables are limited to what they can obtain from the soil, sea vegetables spend their entire lives luxuriating in the world’s largest, oldest, most complete mineral bath. They soak it up and are among the richest sources of iodine, magnesium, calcium, iron, zinc, potassium, manganese, and all other (56 of ‘em in total) minerals essential to the human body. Getting precise numbers for the mineral content of each variety, though, is difficult, because it varies based on location, water temperature, water depth, climate, and season. Rest assured, though, that these things are extremely nutritious, however variable the specifics may be.

There are dozens upon dozens of edible seaweed varieties, so variety should never be an issue. You could conceivably wade out into the shallows of your local coastline, grab a fistful of slimy, slippery vegetation, and consume it without any ill effects. In fact, the only poisonous seaweed I’m aware of is a filamentous, blue-green algae called lyngbya majuscula, or fireweed. Here’s a picture so you know what to avoid. Otherwise, go crazy. Go wild. Try ‘em all. Wild, fresh, dried, or even noodled. Here are a few of the more popular varieties:


Kelp is the most readily available type of edible seaweed. In Asian countries, kombu and wakame are popular forms of edible kelp. You’ll generally find kelp in its dried form; soaking it for several minutes makes it pliable and edible, or you can add it directly to soups for extract the nutrients. Kelp also comes in granulated form, to be used in place of salt or as a mineral supplement to your food. A quarter teaspoon of this brand gives you plenty of iodine (over 2000% of the RDA), so if you’re looking to add more iodine to your diet, this is a fantastic way. If you’re looking to reduce your intake, you might try other seaweeds.


Kombu is a type of kelp, a brown algae most commonly eaten in Japan. It comes dried, for soup or broth, or fresh, to be eaten as sashimi.

Add a five inch strip to a pot of water with a bit of salt and pepper for a simple, mineral-rich broth, or incorporate a few more ingredients and make Aaron Blaisdell’s Kombu Egg Soup. Be sure to eat the chewy kombu after.


Wakame is another popular one in Japan and Korea, where restaurants will often serve fresh (or reconstituted) wakame tossed with a bit of sesame oil over a bed of lettuce. I highly recommend trying this out – the chewy robustness of the seaweed holds up well against the delicate lettuce.

Wakame often appears in miso soups or simple broths, floating on the top in thin strips. It has about the same nutrient composition as kombu and other kelps (iodine, magnesium, calcium, etc).


Arame is brown Japanese kelp used primarily in Japan, China, and Korea, but Peruvian and Indonesian cuisine employs it as well. It has a sweet, mild flavor, making it a great sea vegetable for beginners. Try sautéing soaked, drained arame with winter squash, onions, butter, and a bit of chili pepper for a great side dish for grilled meat or fish. Soak dried arame for five minutes before using (unless it’s going right into a soup). A tablespoon of dried arame will give you 0.7 mg of iodine.


Dulse is a red seaweed that attaches itself to rocks in the North Atlantic and Northwest Pacific oceans. It’s often shredded, dried, and sprinkled on soups, but fresh dulse can be sautéed with butter and garlic, or rubbed with olive oil and salt and roasted in the oven to make chips. I’ve even eaten handfuls straight out of the bag, treating it like edible Big League Chew that won’t destroy your tooth enamel. It has less iodine (by most accounts, about 1/5 of the amount) than kombu, with high amounts of magnesium and calcium. Dulse also comes in shakable flakes, similar to granulated kelp.


Anyone who’s eaten sushi knows nori. It’s the mildest form of seaweed , generally coming roasted in sheets or squares. Compared to other sea vegetables, it’s also fairly low in minerals and other nutrients, but that just means you can eat even more of it. Try wrapping up gobs of tuna salad (tossed in olive oil and balsamic vinegar, sprinkled with kelp granules, perhaps) with your nori squares for a quick, healthy snack, or just eat them plain.

Irish Moss

Also known as carrageen moss (yes, as in carageenan, the common thickening agent that makes up about 55% of Irish moss’ bulk), Irish moss grows along the rocky Atlantic coasts of Europe and North America. It’s also about 15% mineral and 10% protein, and it softens into a jelly-like substance when heated in liquid. Folks in the Caribbean boil Irish moss until it’s jelly, add flavoring like vanilla or cinnamon, and top it off with rum and milk. The concoction is supposed to fight impotence and confer aphrodisiac qualities. The Irish and Scottish boil the stuff to make a tapioca-like pudding dessert. It might be interesting to play with some Primal seaweed pudding recipes, which could be incredibly nutritious (Irish moss is high in iodine, magnesium, calcium, manganese, zinc, bromine, and other minerals) if you avoid sugar. Anyone game?

Alaria Esculenta

Sometimes called dabberlocks, badderlocks, or winged kelp, alaria esculenta is a traditional sea vegetable found in the far north Atlantic Ocean. Greenland, Iceland, Scotland, and Ireland all count it among their traditional foods. It’s a brown seaweed with a large central rib, from which wavy membranes shoot out on either side. Alaria was traditionally dried, then added to soups and stews. A big strip of it goes well in a pot of chili and increases the mineral content considerably.

I understand that some people just don’t dig the flavor of sea vegetables, and that’s fine. Soups and broths are excellent ways to extract the bulk of the useful minerals and nutrients from sea vegetables; eating the stuff itself is entirely optional (although probably optimal). Still, give it a try. For my money, the texture of sea vegetables is unrivaled and incredibly unique.

One thing to keep in mind is that sea vegetables have historically been used as garnishes, flavorants, stock bases, and side dishes. You won’t see heaping piles of kelp replacing spinach or lettuce in salads in Japanese households, for example. Because they’re so incredibly nutrient-and-mineral-dense, sea vegetables can be eaten to excess. Our iodine RDA of 150 micrograms is low. The Japanese typically get upwards of 5-10 mg iodine daily without ill effects (in fact, their traditional health and longevity is rather excellent), but iodine toxicity does exist. Think of sea vegetables as a supplement, albeit a supplement to be used on a regular basis.

Warnings about heavy metal or pollutant toxicity due to consumption of sea vegetables are understandable. If sea vegetables soak up all the beneficial compounds floating around our oceans, it seems plausible that they’d also absorb the bad stuff – mercury, arsenic, lead, etc. Most studies have shown that heavy metal toxicity via seaweed consumption just doesn’t really happen. Only one type, called hijiki, has consistently been shown to possess levels of heavy metals, especially arsenic, that approach toxicity. Avoid hijiki and you should be okay.

I wish I could give accurate, precise figures for mineral and nutrient content of sea vegetables, but I can’t in good conscience. To me, though, that adds a bit of excitement to eating. You know it’s sustained multiple cultures over multiple time periods, and you know it contains the full range of essential minerals – you just do not have the hard numbers in front of you. Well, neither did Grok, nor the Vikings, nor the Pacific Islanders, nor the chronic disease-free Japanese villagers munching on this stuff on a daily basis. It was just there and it was edible and apparently nourishing. I’ll for one continue to get some of my veggies from the sea., FotoosVanRobin, digiyesica, Akuppa, preetamrai, Airstream Life, Travis S. Flickr Photos

You want comments? We got comments:

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  1. Brilliant post here Mark – I’ve always wanted to learn more about what the sea can offer our diets. I’ve had Sea Kelp in tablet form but as always would prefer to eat the true, natural source!

    Luke M-Davies wrote on July 9th, 2010
  2. a couple of these types i can pretty much walk to and pick up at the beach. it would be from an area where quahogs, clams and fish are eaten, so i presume the water is ok. my only concern is the one i have for mushrooms — that being, are there any similar looking seaweeds that are poisonous? i’ve never had the courage to pick wild mushrooms, but seaweed is always washing up, floating off the shore and attached to the rocks.

    jeff wrote on July 9th, 2010
  3. Just a comment about the iodine and toxicity. Iodine can flush out heavy metals like lead, cadmium,arsenic and mercury out of the tissues and leave the burden on the kidneys and liver to eliminate. This most likely is where the negative effects of high iodine intake comes from. These metals along with chlorine, fluorine and bromine are released from the tissues and are all toxic to the thyroid and body. People with low iodine levels will also store more of these toxic halides. Seaweed on the other hand has substances that bind to heavy metals and offset the toxicity of releasing these heavy metals via the iodine. I can’t say that hijiki’s high arsenic content is neutralized by the seaweed’s sodium alginate, but it does bind up and remove heavy metals. People with Hashimoto’s thyroiditis (most common hypothyroid) will benefit, but be more sensitive to iodine. (They will also improve greatly by going gluten-free.)

    Will Mitchell wrote on July 9th, 2010
  4. Wow, I just picked up a package of arame and threw it into a crockpot with homemade chicken stock, because it looked kind of like noodles. Talk about timely! I just wish I could find seaweed more readily — I love me a good seaweed salad.

    Deanna wrote on July 9th, 2010
  5. If you want my opinion, I would stay clear of Irish Moss because of the Carrageenan:

    I’m personally dealing with a leaky gut and I’ve been taking Ohhira’s probiotic formula witch contains carrageenan and saw my problems getting worse. I also imagine that the amount of carrageen in the probiotic was minimal, yet it still had an effect on me.

    Sebastien wrote on July 9th, 2010
  6. Cooking with sea vegetables was one of the great ideas I kept from my years as a Macrobiotic cook–there are some good recipes you might find in an old Macro cookbook. Actually I learned a lot of good things from that expererience–just not the heavy grain/rice based aspect of it.

    Debrah wrote on July 10th, 2010
  7. I love that irish moss was included! it is a key ingredient in beer making. Now I know my beer has that extra nutritionl oomph.

    frygal wrote on July 10th, 2011
  8. Whole Foods has a huge selection of sea veggies. I get all of mine there. Rinsing or not rinsing is really a matter of personal preference, in my opinion. When we throw these into miso soup, which I eat almost every day, I never rinse them. I also love certain ones not wet at all, just really crispy, straight from the bag. Some of them take some getting used to, but the health benefits are remarkable. My hair and skin have never looked better!

    Dana Vigilante

    Dana Vigilante wrote on July 13th, 2011
  9. Well, crap!
    I bought a small bag of Hijiki yesterday because I thought it would be healthy.
    Then I come here and read I should avoid it because it’s loaded with toxic metals.
    The bag wasn’t cheap, but I guess it didn’t taste all that great anyways, kinda has no flavor at all, just stringy, difficult to get soft. I guess my dogs will get some sea algae with their next meal…lol.

    Arty wrote on October 12th, 2011
  10. Mark,
    There are two other alternatives to eating sea veggies. As you pointed out, along with all the good minerals in seaweed, there is also the bad, such as lead and arsenic.

    One alternative is to consume a trace mineral supplement. There is a source of trace minerals that is derived from a deposit in Mississippi of all places. The deposit is actually a long buried pile of seaweed and other stuff that settled into a long depression some 25 million years ago. The material was covered before the ocean retreated, since the whole area was once a shallow sea. The minerals derived from the trace mineral laden clay are complete (70+), plant derived and human available.

    The best info on the minerals (online) is at this site:
    I have NO financial connection with this company. I just know where their minerals come from and they have done a good job documenting the info about minerals and this particular deposit.

    I get the minerals I put into my fertilizer products from the same source (different property but same area).

    As I, I manufacture organic fertilizer, and this brings me to the other way that anyone can get the minerals they need in their diet. As you mentioned, most farm land is VERY deficient in minerals of all sorts and trace minerals especially. It is VERY easy to grow nutrient dense food right in your own back yard IF you use organic growing methods and supplement your soil with trace mineral fertilizer.

    I have more information on my Facebook page on growing nutrient dense food. If anyone is interested, here is the link.

    Good job as always and keep up the good work.

    Michael in Alabama

    Michael wrote on March 12th, 2012
  11. I hate fish and anything from the sea – unfortunately. So do these have any fishy taste what so ever?? Im very sensitive to a fishy taste.
    Would it be advisable to eat them if you have an over active thyroid?

    sharyn wrote on April 15th, 2012
  12. I have tried to find a really basic site showing me a good picture of seaweed, its name besides it with either recipes or how to cook it. I am looking for seaweeds in SW England and South Wales. Any ideas please???

    Tony Lock wrote on July 26th, 2012

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