When most people hear “seaweed,” they think of sushi wrapped in nori—those familiar, dark green sheets that add a savory touch to Japanese rolls. But seaweed, or sea vegetables as they are also called, encompass a vast and diverse group of marine plants that are surprisingly underappreciated in many Western diets. Beyond sushi, these oceanic greens offer a rich array of flavors, textures, and most importantly, incredible nutritional benefits that can transform your meals and boost your health.
A World of Seaweed: Over 15,000 Varieties
Seaweed isn’t just one thing—it’s a sprawling family of plants classified primarily by their color: green, red, or brown. This color distinction reflects their chlorophyll content and the depths at which they thrive.
- Green seaweed like sea lettuce floats near the water’s surface, basking in sunlight to fuel photosynthesis.
- Brown seaweed such as kelp and bladderwrack grow several feet underwater, flourishing in cooler, deeper waters.
- Red seaweed, including nori, dulse, and Irish moss, live even deeper in the ocean.
Each variety brings unique flavors and nutrients, making seaweed a versatile ingredient for adventurous cooks.
Nutrient-Dense Superfood from the Sea
What truly makes seaweed extraordinary is its nutrient profile. Sea vegetables contain 13 essential vitamins, 60 minerals, 23 amino acids, and an abundance of natural salts—far exceeding what most land-based vegetables offer. Rich in B vitamins, including the rare plant-based B12, seaweed also provides impressive levels of vitamins A, C, D, E, and K. Some seaweed types boast more vitamin C than oranges!
Seaweed’s mineral content is particularly remarkable. Thanks to its ability to absorb minerals directly from seawater, it contains exceptionally high levels of iodine—over 1,000 times more than any land plant—which supports healthy thyroid function and helps detoxify harmful substances like heavy metals and free radicals. It also contains iron (sea lettuce has 25 times the iron content of beef by weight), calcium, magnesium, potassium, selenium, zinc, and more.
Immune-Boosting and Protective Compounds
Beyond vitamins and minerals, seaweed packs bioactive compounds that enhance immune function and protect against disease. Fucoidan, a compound found in brown seaweed, stimulates the immune system, while a broad spectrum of antioxidants combats oxidative stress—a driver of chronic illness. Seaweed is also rich in essential fatty acids like omega-3 DHA, known for heart and brain health. Its antibacterial, antiviral, and antiparasitic properties make it a natural defender against infections.
Harvesting vs. Buying Seaweed
For coastal dwellers, fresh seaweed can be harvested responsibly in clean, unpolluted waters during spring and summer low tides, especially after storms when fresh seaweed detaches but retains vibrant color. Freshly gathered seaweed should be rinsed with seawater—not freshwater—and stored cold. It can be consumed fresh, refrigerated for a few days, or dried for long-term storage by air drying or low-temperature oven baking.
For most, however, the simplest way to start is buying prepackaged dried seaweed from trusted grocery stores or online retailers. This convenient option allows easy integration of sea vegetables into everyday meals.
How to Use Seaweed in Your Cooking
Dried seaweed can be sprinkled directly into soups or rehydrated in warm water and added to salads, stir-fries, and grain bowls. Seaweed flakes like dulce can be used as a nutrient-rich seasoning, similar to salt, enhancing flavor with a savory umami punch.
Common types and uses:
- Brown Seaweed:
- Kombu: Soften dried kombu and add it to bean dishes to reduce gas and enhance digestibility. Use in soups or wrapped around fish.
- Wakame/Alaria: Delicious in miso soup, casseroles, and grain dishes.
- Arame: Soak and add to stir-fries or scrambles.
- Bladderwrack: Brew into mineral-rich teas.
- Red Seaweed:
- Dulse: Cook like spinach or enjoy as chips; also available as a seasoning.
- Irish Moss: Natural thickener for soups and jellies.
- Nori: Sushi wraps or crumbled into dishes for a flavor boost.
- Green Seaweed:
- Sea Lettuce: Use fresh in salads with lemon or roast and crumble over grains and veggies.
Simple Recipes to Get You Started
Bladderwrack Tea:
Simmer dried bladderwrack in water for five minutes. Add fresh grated ginger, strain, and sweeten with honey if desired for a soothing, mineral-rich drink.
Cashew and Wakame Dressing:
Blend cashews, avocado, dried wakame, miso paste, tahini, and garlic until smooth. Season with sea salt, black pepper, and cayenne. Drizzle over salads or steamed veggies.
Stir-Fry Sea Greens:
Sauté ginger, garlic, scallions, and crushed peanuts with vegetable broth. Add chopped bok choy, carrots, zucchini, and rehydrated kombu. Toss with hoisin sauce, tamari, and rice vinegar. Serve over brown rice or another whole grain.
Why Incorporate Seaweed into Your Diet?
Sea vegetables are an exceptional way to elevate your nutrition, supporting thyroid health, boosting immunity, and providing essential nutrients often missing from modern diets. Their unique flavors add delicious complexity to meals, from salads to stews. Whether you’re seeking better health, culinary adventure, or a deeper connection with the natural world, seaweed offers a rich, sustainable, and healthful choice.
Dive into the ocean’s bounty and discover how these jewels from the sea can enhance both your plate and your well-being.
Sandra Musial, MD, co-founder of Plant Docs, specializes in food as medicine, advocating whole, plant-based nutrition to prevent and reverse chronic disease.