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Eat seaweed for the health benefits - but don’t overdo it

NUTRITION

Kelp is on the way

Seaweed, categorized as red, green or brown algae, are high in vitamins, minerals and many other nutrients.

Seaweed may be the newest superfood, but as Adriana Barton reports, despite the nutritional benefits of nori and wakame, it's possible to go overboard

When seaweed wriggles its way into cookies, crackers, spaghetti – and beer – there's no doubt that marine algae is having its day.

A growing appetite for seaweed such as kombu, nori and wakame is quickly expanding the world's seaweed industry, valued at $6.4-billion (U.S.), according to a 2016 report from the United Nations University in Tokyo (based on 2014 data).

Already, global production of seaweed by tonne exceeds that of lemons and limes. Trendcasters from the Atlantic Magazine, Fiscal Times and NPR have declared seaweed "the new kale."

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Seaweed has achieved delicacy status at high-end restaurants such as Sooke Harbour House on Vancouver Island, which serves it raw, deep-fried, pickled, smoked or wrapped around B.C. halibut. Small businesses have caught the wave, too, adding the versatile ingredient to a wide range of specialty items that make the most of seaweed's exotic cachet.

Kelp Stout, released in 2014, is a "really good seller," says Heidi Fifield, retail manager for Tofino Brewing Co., who described the quaff as having a "dark chocolate and sea salt quality."

Then there's Kelp Caviar, launched in 2012 by Naor Cohen of Montreal, who wowed business tycoons on CBC's Dragons' Den with his fish-free product.

To meet this year's demand, Cohen produced the equivalent of 150,000, 100-gram jars of pearl-shaped seaweed caviar, in flavours ranging from sturgeon to salmon.

While Asian countries have always held seaweed in high esteem, Western demand for the slippery stuff is driven by the novelty factor and seaweed's reputation as a "superfood."

Seaweed, categorized as red, green or brown algae, are high in vitamins, minerals and many other nutrients. Researchers are studying whether seaweed consumption may protect against health conditions ranging from breast cancer to cardiovascular disease. But as with most foods, it's possible to go overboard on marine algae. Doctors have reported rare but serious cases of excess iodine and heavy metal toxicity in patients who consumed too much seaweed or seaweed supplements.

If you're keen to add more seaweed to your diet, here's what experts in the nutrition field have to say about how to enjoy it safely.

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Sea palm (Postelsia palmaeformis): This kelp species grows on the Pacific coast, on rocky shores with constant waves.

Eat small amounts for the health benefits

Seaweed is high in iodine, iron, vitamin C (which aids iron absorption), antioxidants, soluble and insoluble fibre, vitamin K, vitamin B-12 and a range of other nutrients important for human health. Red seaweed such as dulse are high in protein. What's more, seaweed contain certain compounds not found in terrestrial food sources, including fucoidan, a type of carbohydrate that has anticoagulant and antiviral properties. Numerous studies have linked the Japanese diet – high in fish, seaweed, soya, fruits and vegetables – to lower rates of cardiovascular disease, Type 2 diabetes, obesity and cancers in general. Studies such as these do not isolate the effects of seaweed from other dietary and lifestyle factors, notes Dr. Mary Hardy, a medical authority on dietary supplements and former medical director of the Integrative Medicine Clinic at Cedars-Sinai Hospital in Los Angeles. But based on evidence of seaweed's disease-fighting potential from cell and animal studies, she says, "I do think this is a nutrient-rich superfood."

Dulse (Palmaria mollis): A patented strain of dulse developed by aquaculture researcher Chris Langdon at Oregon State University to grow faster than wild dulse.

A little goes a long way

Think twice before replacing wheat pasta with a big bowl of seaweed "spaghetti" shaped like the real thing. Iodine levels in seaweed vary widely depending on the species and where they are grown, says Vesanto Melina, a registered dietitian and co-author of Becoming Vegan: Comprehensive Edition (and Express Edition). With just 1.5 teaspoons of arame seaweed, for example, "you've reached the tolerable upper limit for iodine consumption per day." Too little iodine can cause thyroid problems, but so can too much, she says, adding that few North Americans are iodine deficient because our table salt is iodized. While seaweed makes up to 10 per cent of the Japanese diet, seaweed is traditionally eaten in combination with vegetables such as broccoli, cabbage and soya, which inhibit iodine uptake by the thyroid gland.

Kelp supplements may be helpful for patients with specific health conditions, or those undergoing chemotherapy, but Hardy recommends against taking them without guidance from a health-care professional. Some seaweed are high in vitamin K, which may interfere with blood thinning medications such as warfarin. High potassium levels in seaweed such as dulse may cause nausea and weakness in patients with kidney problems, since their kidneys can no longer remove excess potassium from the body.

Arame (Eisenia bicyclis): A Japanese seaweed variety prepared with onion, peas and carrots.

Consider the source

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Seaweed absorbs essential minerals like a sponge. But depending on where they are grown, they may also soak up environmental toxins and heavy metals. Health authorities have warned against eating hijiki, a Japanese seaweed known to absorb dangerous levels of arsenic. Seaweed companies with organic certification are more likely to harvest seaweed in protected coastal areas, away from heavy shipping channels and effluent sites, Hardy says. Wild seaweed may be more nutritious than farmed, she adds, since "we're not completely sure if we lose something in that transition from the wild to the aquaculture environment."

Watch for additives

If you are wary of food dyes, don't gorge on the brilliant green seaweed salad served at Japanese restaurants (its true colour is mousy brown). Packaged seaweed snacks – those addictive wafers of oiled nori (also called laver) – typically have loads of sodium added to a naturally salty food, so look for lightly salted varieties. And if you have digestive problems, stay clear of products such as ice cream and yogurts that include carrageenan in the ingredient list. While carrageenan is derived from seaweed (Irish moss), carrageenan gum is a heavily processed food additive that researchers have linked to inflammation in the gut.

The best way to eat seaweed is to add small amounts to everyday foods, Hardy says. "If you have miso soup with seaweed in it, that's a traditional way to use it."

Seven seaweeds to try

Arame

Soaked arame looks like brown shoelaces and has a mild, almost sweet flavour. Add it to edamame beans, or stir-fried Japanese soba noodles with shiitake mushrooms.

Dulse

This purple-red seaweed is easy to find on the East Coast. Nova Scotians snack on it dry from the bag, or buy it in flakes to sprinkle on soups. Pan-fried until crisp, dulse has a bacon-like flavour. BonAppetit.com suggests slapping it between two slices of bread with lettuce, tomato and mayo to make a "DLT."

Wakame (Undaria pinnatifida): This Asian kelp (an invasive species on California shores) was scanned by Josie Iselin, author of An Ocean Garden: The Secret Life of Seaweed.

Wakame

If you have sipped miso soup, you have probably tried this rubbery seaweed. Julie Drucker of Yemaya Seaweed Co. recommends serving soaked and sliced wakame with a dressing of garlic, ginger, honey, sesame seed oil and tamari.

Sea palm

Named for its palm-like fronds, this mild, almost nutty-tasting kelp grows only on wave-washed rocks on the West Coast of North America. For a light salty snack, coat it with olive oil and garlic and bake in a medium oven for 10 minutes until crunchy.

Kombu (Laminaria setchellii): ollected in Cambria, Calif., and scanned by Josie Iselin, author of An Ocean Garden: The Secret Life of Seaweed.

Kombu

A natural source of umami, the "fifth taste" in Asian cuisine, kombu is the main ingredient in Japanese dashi soup. The Okinawans of centenarian fame eat more kombu per household than anywhere else in the world (mainly in dashi soup). Powdered kombu is a natural substitute for the artificial flavour enhancer MSG (monosodium glutamate).

Nori (Porphyra umbilicalis): Nori is typically shredded and rack-dried in a process that resembles paper-making. This specimen was scanned by Josie Iselin, author of An Ocean Garden: The Secret Life of Seaweed.

Nori

The papery wrapping for sushi rolls is never soaked before serving. Eat it toasted, or wrap a nori sheet around a ball of rice stuffed with salmon-mayo filling to make DIY onigiri – the on-the-go snack sold in Japanese convenience stores.

Irish moss (Chondrus crispus): Red seaweed species scanned by Josie Iselin, author of An Ocean Garden: The Secret Life of Seaweed.

Irish moss

This red Atlantic seaweed resembles curly lettuce and adds colour and flavour to salads. A staple during the Irish famine of 1845 to 1852, it was traditionally used as a thickener for soups and puddings. Irish moss is the source for carrageenan gum, a food additive associated with digestive problems, but the unprocessed seaweed is considered nutritious and not known to cause gut issues.

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