by Nusheen Orandi
We call it an exotic “health food” now, but edible seaweed became part of the world’s cuisine thousands of years ago and still remains a normal kitchen ingredient in many parts of the world. Why should we pay more attention to the stuff that gets stuck in between our toes at the beach? While western chefs and foodies play catch-up to the rest of the world by switching up their vegetable dishes, nutrition scientists say seaweed offers health benefits. Perhaps both contribute to why U.S markets are starting to make room for this sea vegetable on grocery shelves.
The health benefits of edible seaweed
Edible seaweed can be a good source of vitamins, minerals, and other nutrients and hosts many health benefits that can add value to our diets. The nutrient content of seaweed can depend on the variety. People harvest green, red, and brown seaweed in Japan, China, Korea, the Philippines, India, New Zealand, and many other parts of the world. There are over 30 commonly eaten seaweeds.
Seaweed is rich in complex carbohydrates and protein, with red seaweed containing the most protein. Seaweed also contains omega-3-fatty acids, which have been shown to promote heart health by lowering triglyceride levels (bad fat) in the blood. Seaweed is comprised of fiber as well. About a ¼ cup serving of fresh seaweed, or a couple tablespoons of dried seaweed (like nori), has approximately one gram of fiber.
As an antioxidant-rich vegetable, seaweed provides us with some of the immune-boosting vitamins such as vitamin A, C, and E. A single serving of seaweed (about two tablespoons) also gives about a fifth of the daily recommended amount of vitamin K, which plays an important blood clotting role in the body and helps maintain bone health. But, it is the vitamin B12 in seaweed that may really pack a nutritional punch. Dr. Jeffrey Blumberg, director of the Antioxidant Laboratory at the USDA’s Human Nutrition Center on Aging at Tufts University, explained why: “It’s not just important to look at the nutrients present in a food, but how readily those nutrients are released once you eat it.”
The healthfulness of a food depends on how much of a nutrient is released once we eat it (its bioaccessibility) and how much of that nutrient our body can take up (its bioavailability). So, nutrients in a food are only useful if the body can take them up in the first place. This makes seaweed curious because most plants do not contain bioavailable vitamin B12. Research conflicts with whether the vitamin B12 in seaweed really is bioavailable or not. For example, it has been shown to be bioavailable in the red seaweed known as purple laver, which is usually sold dried. But it is not clear if other edible seaweeds have bioavailable sources of vitamin B12. However, this potential source could benefit people trying to include more plants in their diet. It would also suit vegetarians, who usually have few food sources of vitamin B12. Animal foods, such as red meat, act as the main source of vitamin B12, however nutrition professionals recommend that most healthy diets should consist of less red meat.
What gives seaweed its high mineral content? Some scientists suspect it is the exposure to ocean minerals. Seaweed has plenty of minerals like calcium, potassium, magnesium, iron, iodine, zinc, selenium, and copper, which have diverse functions in the body. A single serving of seaweed (particularly green or brown seaweed) provides over half of the daily-recommended amount of calcium. In fact, the calcium found in seaweed (calcium phosphate) is more bioavailable and useful to our body than the calcium found in milk (calcium carbonate). Seaweed is a major source of iodine. Brown seaweed contains the most iodine, while green and red seaweed contain less. The other primary source of iodine is iodized salt. But, as Dr. Blumberg noted, “If people are being told to decrease salt intake in their diet, then that means that they are also taking in less iodine in their diets.” This especially applies to heart patients on low-salt diets that may be at risk of iodine deficiency.
The health risks of edible seaweed
Seaweed can pose risks for some people. For example, people with thyroid health problems would do best to avoid large amounts of brown algae because of its high iodine content. A person with kidney problems could also be at risk because red seaweed, such as dulse, is very high in potassium and could present a risk of potassium toxicity.
What makes seaweed any better than the usual green veggies, like broccoli and lettuce? It’s not so much that it’s superior to other vegetables, but that it can add variety to a healthy diet that, as Dr. Blumberg said, should lean in a plant-based direction.
“I would argue that one of the things we need people to do is to eat more plant food. And, that can be done with one of the principles of nutrition: diversity of the diet. A healthful food doesn’t have to be a ‘superfood,’ just a good, nutrient-dense food,” he said.
So edible seaweed is full of good things. But, how are we supposed to eat this mildewy-looking green stuff? Cooking with seaweed may seem like a high dive, but you can actually easily work it into any meal or snack.
Cooking with edible algae
You don’t need to learn how to roll sushi in order to cook with seaweed. Different types of seaweed, fresh or dried, add unique flavors to soups, meats, salads, and snacks.
Kelp is a popular form of seaweed, usually dried, that people cook with. Kombu, a brown kelp, is one of the most common types. It comes in dried sheets in most grocery stores. You can rehydrate it by adding water to be used in salad, stir fries, or with fish. You can even add it dried to soups or rice dishes for flavor. As it gets cold out there, try out this Seared Salmon with Winter Vegetables and Kombu Broth recipe.
Did you know you could add a vegetable to your popcorn? Well, with red seaweed, you can! Dulse, red seaweed, is sold in the form of dried flakes, which gives it the nickname “sea lettuce flakes.” It has a naturally salty flavor and chewiness that dresses up your popcorn nicely. Just add about ¼ cup of dulse flakes to your favorite bag of popcorn kernels, and let it pop!
If you try a seaweed salad in a Japanese restaurant, its main ingredient is probably wakame. You buy wakame dried, but once you add water to it, it turns into a dark green and slightly crunchy vegetable. Cucumbers and sesame seeds complement wakame in a salad, such as this easy Sunomono (Cucumber Salad) recipe.
The most well known seaweed is probably nori, a dark green seaweed. It’s often seen as sushi’s belt and adds a salty and vinegar flavor to seafood. You find nori as dried sheets, just like kombu. You can break it up and add it to your trail mix, or cut it up into strips and use it as a healthy cracker substitute for an appetizer. Get fancy with this Tuna Tartare and Nori Chips recipe.
Arame is a funky, dark brown kelp that comes in dried, long strands. It actually tastes slightly sweeter than other kelps and adds flavor to an assortment of dishes. Arame brings a blend of texture to a dish, such as in this Arame and Edamame Salad, where you get creamy and crunchy all in one bite.
Remember when trendy kale chips swept through Whole Foods? Seaweed chips naturally have lots of flavor and also provide a healthy alternative to even our guiltiest snack cravings. Roast 3-4 cups of seaweed with a teaspoon each of salt and pepper and a dash of lemon juice.
If the vegetable drawer of your refrigerator tires you out, adding this flexible and flavorful sea vegetable to your meals could benefit both your health and your palate.
Nusheen Orandi is a second-year student from California in the Nutrition Communication program with a concentration in Agriculture, Food and Environment. She likes to spend her time tea-shop hunting, breakfasting, tensely watching the Tottenham Hotspurs, and cooking and eating with friends and family.