Jane Says: Eating Kelp Isn’t Going to Make You Radioactive

Sea vegetables are good for your health and food for the environment.

Sea Vegetables Like Kelp Are Safe and Healthy to Eat

(Photo: Justin Lewis/Getty)

Jane Lear was on staff at 'Gourmet' for almost 20 years.

“The TakePart piece on kelp was very interesting, but in light of all the comments about radiation and heavy metals, I’m really confused. Is seaweed safe and healthy to eat or not?”

—Douglas Green

Kelp and other seaweeds—macroalgae that grow wherever land and ocean meet—are a safe and very healthy addition to your diet unless they are contaminated by sewage or industrial, agricultural, or radioactive wastes. For millennia, after all, coastal peoples all over the globe have survived and thrived on them. Today, in addition to Japan and other parts of Asia, they’re a popular food in Britain, in places that don’t have many indigenous vegetables (such as Iceland), and, increasingly, at high-end American restaurants such as Louro, in Manhattan, where chef David Santos has integrated kelp from Brendan Smith’s Connecticut shellfish farm into cocktails, salads, sides, and main courses.

And it would be a real shame to avoid supporting sustainable kelp businesses in the United States and elsewhere because of fears about radiation and pollution.

It’s true that seaweeds, like bivalves, act as very efficient saltwater filterers, absorbing heavy metals and nitrogen-based pollutants such as those in agricultural runoff.

And it’s true that, even though our exposure to radiation has always been an everyday occurrence, and radiation waste in our oceans has been an unfortunate fact of life for the past 50-odd years, the sheer scale of Fukushima Daiichi—the Japanese nuclear power plant that has spewed and/or leaked thousands of tons of radioactively contaminated water into the Pacific since 2011—is enough to give anyone the shivers. How this tragedy will affect marine plants and animals in the long run is unclear. About a year after the plant was crippled by the one-two punch of an earthquake and tsunami, for instance, giant kelp off the California coast was found to be contaminated with Fukushima radioisotopes. But just one month later, the kelp contained no detectable amounts. (For the abstract of the study, click here.)

It’s also true that one logical question always seems to get skipped over in a filterers-as-food discussion: Are the same seaweeds or bivalves that are absorbing All That Shit ending up on dinner plates or an extravagant plateau fruits de mer on bistro night?

The answer is no, and you can thank some of the most stringent regulations (our tax dollars at work!) and most rigorous scientists and farmers in the world. “Our seagreens are grown in certified waters, tested weekly, and traceable from farm to plate,” wrote Bren Smith in a recent email. In addition to cultivating kelp in pristine waters for food, he’s also helping scientific cohorts at the University of Connecticut grow it in polluted waters to rehabilitate them (the waters, not the scientists), and that kelp is destined for biofuel. One of the fastest-growing plants in the world, kelp could outproduce corn or soybeans as an alternative energy source.

In fact, it seems from an environmental standpoint, there is no downside to kelp. I’m not talking about the wild-harvesting of vast quantities of seaweeds for their phycocolloids—polysaccharides such as carageenan, algin, and agar that are used as stabilizers, emulsifiers, and bulking agents in a bazillion food, beauty, and industrial products. (Just typing the words “wild-harvesting” and “vast quantities” in one sentence makes me queasy.) Mindful cultivation leaves a much smaller footprint on the marine ecosystem.

“Kelp can be farmed over a small surface area because it is grown vertically. This limits interference with aquatic life,” wrote Mike Grandy in a Georgetown International Environmental Law Review blog post.

“More importantly, kelp acts as a nitrogen sink: it soaks up nitrogen in the surrounding water to fuel its growth. This effect can be especially beneficial in waters with a significant amount of terrestrial runoff, as this runoff is often saturated with nitrogen from conventional land-use fertilizers …. Kelp is also being studied for its potential as a carbon sink. Plants essentially ‘capture’ excess carbon dioxide through photosynthesis, which lowers the amount of carbon dioxide in the atmosphere. Kelp could provide a means of growing more plant matter, which could help to bind up excess carbon. This binding process reduces the amount of C02 present in the atmosphere. Perhaps more importantly, an oceanic carbon sink like kelp could ease the production of carbonic acid in the oceans themselves.”

Still not quite ready to dish up a plate of kelp pasta or seaweed salad? Well, nutrition-wise, seaweeds—or sea vegetables, as they’re often called—are a concentrated source of vitamins, minerals, protein, and heart-healthy omega-3 fatty acids. They also contain the trace element iodine 127, the “good iodine” (found in seafood, dairy products, and iodized salt), which the thyroid gland needs to make hormones.

And even though we tend to think of iodine deficiency as a problem in the developing world (it is the leading preventable cause of mental retardation), it’s important to realize that it has risen in the United States, too, as a result of a change in commercial breadmaking (bromine has replaced iodine as an additive) and an avoidance of iodized table salt. Counterintuitive news flash here: Unlike seafood and seaweeds, sea salt is not naturally rich in iodine.

So eat your (sea) vegetables! Eden, the oldest organic-food company in North America, addresses radiation concerns about their Japan-sourced products right up front. And two outfits I know of that specialize in North Atlantic sea vegetables are Ocean Approved, in Portland, Maine (transitioning from small-scale harvesting to mariculture, their products include salad-cut kelp and kelp noodles), and Maine Coast Sea Vegetables, which harvests North American dulse, kelp (aka North Atlantic kombu), Alaria (North Atlantic wakame), laver (aka nori), sea lettuce, bladderwrack, and Irish Moss. And if you live near Bren Smith’s Thimble Island Oyster Company, in Branford, Connecticut, check out his oyster, clam, and kelp offerings for his 2014 CFA, the first Community Supported Fishery in Long Island Sound.

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