Seaweed is a superfood. (Here's why, and what to do about it.)

The volume of Earth’s oceans are about 300 times that of the terrestrial habitats on Earth and are home to countless species of living creatures.  So it makes sense that sea vegetables (aka "seaweed") would provide significant sources of nourishment and medicine.

This has has been common knowledge in the East for thousands of years.  The average Asian daily consumption of sea vegetables is about 8 grams (dry weight) of seaweed. 21 different species are eaten in Japan (where there is also a National Seaweed Day!), over 40 in Korea, and over 30 in the Pacific islands.

But in the West, we have little idea what to do with sea vegetables (aside from using dried  nori in sushi). Let’s start with the basics:

What is seaweed?

sea lettuce

Technically, seaweed is algae.  There are many types of seaweeds, categorized as brown (kelp,  kombu, hijiki, wakame), yellow-green (sea lettuce), blue-green (blue-green algae) and red (nori, dulse, Irish moss).  The color of seaweed depends on the spectrum of light available for its photosynthesis, which is determined by light exposure, tides, temperature, and water depth, among other factors.

What’s in it?

As a group, sea vegetables are extraordinarily nutrient-dense.

Because of the way they concentrate minerals, seaweeds contain the broadest range and greatest amount of these important nutrients than any other organism.  

“Consider that our blood contains all one hundred or so minerals and trace elements in the ocean,” writes Paul Pitchford in Healing with whole foods: Oriental traditions and modern nutrition, “Seaweeds contain these in the most assimilable form because their minerals and elements are integrated into living plant tissue.”  Because they’re so dense in minerals, adding just a small amount of sea vegetables to the diet can greatly increase our overall nutrition—and by extension, improve our overall health.

kombu

Seaweeds are exceptional sources of iodine, calcium, and iron.  In comparison to animal-derived foods such as milk, beef, and shellfish, these amazing vegetables are often better sources of these essential nutrients.  Some seaweeds (including hijiki and wakame) tenfold the calcium as milk.  Sea lettuce has twenty-five times the iron as beef.  And depending on where and when it’s harvested, kelp can contain three thousand times the iodine of fish! 

Sea vegetables are rich in fiber (like alginate) and polysaccharides, which support healthy elimination and account for their soothing and mucilaginous properties. Some, like nori and kombu, are even rich in protein. But while seaweed is often cited as a good source of vitamin B12, especially for vegetarians, that may not be the case.  A form of B12 known as B12 analogues make up much of this vitamin’s content in seaweed, and it’s not as easily available to the body—meaning that seaweed may not be a viable source of B12. 

hijiki

But seaweed still packs in the vitamins: it’s high and vitamins A and  C (the latter increasing the bioavailability of iron), and it has a better calcium-magnesium ratio than dairy foods.  It’s also a good natural source of vitamin D, necessary for absorption of calcium and good bone health and muscle function.

How does seaweed impact my health?

In Chinese medicine, seaweed has been used for millennia as a diuretic for swelling and edema, and to soften and detoxify any hardened tissues, such as lymph nodes and tumors.  It is said in ancient Chinese texts that “there is no swelling that is not relieved by seaweed.”

And there’s also a wealth of modern evidence for seaweed’s great health impacts.  Seaweed is a good food for weight loss.  A study published last year by researchers at Newcastle University found that alginate found in kelp reduces the body’s fat uptake by more than 75 percent.  Not only that, many seaweeds are nearly calorie-free!

The sulfated polysaccharides in seaweed have an anti-inflammatory effect on the body’s tissues, especially rejuvenating the digestive tract and the lungs.  Seaweed blocks virus binding sites on our cells, making it effective against herpes and other viruses.  Seaweed is anticoagulant and blood thinning.

One of the unique abilities of sea vegetables is to remove heavy metals from the body, converting them to salts which can then be excreted through the intestines.  Seaweed is also said to detoxify the body of radioactive wastes. 

wakame

Sea vegetables may be helpful in eliminating excess estrogens from the body, important since too-high levels of these hormones are associated with reproductive disorders like fibroids, ovarian cysts, and even cancers, including breast,  uterine and cervical cancers. Japanese women who eat a traditional diet efficiently eliminate 2-3 more times the excess estrogens than women in the US.  

High iodine levels are known to downregulate the thyroid—so people with hypothyroid conditions might want to avoid eating excessive seaweed.  And those taking anti-coagulants such as Coumadin (warfarin) should also be aware that seaweed could potentiate the blood-thinning activity of these drugs.  However, this same activity can be beneficial in preventing hardening of the arteries and lowering blood pressure, and preventing stroke.

How can I add seafood to my diet?

Here are a few uber-easy ways:

Miso-veggie soup

I love making this soup, which also contains probiotic miso and immune-boosting shiitakes and green onion. 

1 oz. wakame or arame seaweed
2 tsp sesame oil
3/4 cup bok choi, sliced finely

Several shiitake mushrooms, sliced finely
8 cups organic (or homemade) vegetable stock
5 tbsp red miso
3 green onions, finely sliced

a few slices of fresh ginger
tofu, cubed (optional)

Soak the seaweed for 10 minutes in a bowl of cold water.  Meanwhile, heat the sesame oil in a large pot and saute the bok choi, mushrooms and ginger at medium heat.  Add vegetable stock.  Drain the seaweed and add it to the soup—turn down the heat and simmer (don’t boil) for 8-10 minutes.  Dilute the miso paste with a bit of stock and add it to the soup.  Add the green onions and serve.

Sauteed Sea Lettuce

This recipe from http://creativehomesteading.blogspot.com, is also simple to make (and it’s also great as a cold salad the next day).

nori

Roasted Seaweed Snacks

If you’re not the cooking type—don’t worry.  Inexpensive, prepackaged roasted seaweed snacks have crossed over from Asian markets to mainstreams stores including Trader Joe’s.  They’re a tasty, salty, crunchy alternative to chips (Annie Chun’s, anyone?) and at just over a dollar, they’re certainly cost-effective—but watch the seasoned varieties for sodium content.