Seaweed – Types, Properties and Uses of Seaweed

Marine macroalgae, thriving in oceanic environments, exhibit an exceptionally high mineral content—often ten to twenty times greater than that of terrestrial plants. They also serve as a rich reservoir of vitamins and trace elements essential for human metabolic functions. Seaweeds are attributed with a multitude of beneficial properties, including the capacity to decelerate aging processes, facilitate weight management, and enhance skin health. Certain species even demonstrate the ability to chelate and eliminate radioactive isotopes and toxic heavy metals from the body. Regular consumption contributes to improved skin elasticity and hydration, a result of their potent antioxidant activity. Furthermore, seaweeds play a role in stabilizing blood glucose levels and reducing cholesterol concentrations, making them a valuable dietary component for individuals with metabolic disorders. They bolster immune function, accelerate lymphatic detoxification, and exhibit alkalizing effects, thereby aiding in the maintenance of acid-base homeostasis. Due to their substantial iodine content, they stimulate thyroid activity and support hormonal balance. These marine plants are particularly abundant in macro- and micronutrients such as calcium, iron, iodine, copper, zinc, fluorine, and phosphorus, which are present in highly bioavailable forms owing to their integration within living plant tissue. Additionally, they provide a significant source of B vitamins (including the rarely plant-derived vitamin B12), as well as vitamins A, C, E, K, and niacin, while remaining low in fat. Given their vitamin B12 content, they are especially recommended for individuals adhering to vegan or vegetarian diets. Seaweeds also contain substantial amounts of dietary fiber, particularly water-soluble fractions, which beneficially influence intestinal motility and overall digestive system health.

Seaweeds constitute an extraordinarily diverse group of organisms classified based on both their geographical distribution and pigmentation, which depends on the availability of light for photosynthesis. In traditional East Asian cuisines, species such as wakame, kombu, hijiki, arame, and nori predominate, whereas on the British Isles, historical diets included Irish moss, dulse, and sea lettuce. In Poland, the only representative with documented medicinal properties is the protected bladderwrack—a brown algae that supports the treatment of hypothyroidism, obesity, hypertension, and thrombus formation. Based on photosynthetic pigment content, we distinguish green algae, brown algae, red algae, and cyanobacteria, among which the most commonly utilized in culinary and supplementary applications are agar-agar (a mucilaginous product from "agarophytes"), dulse (rich in iodine and manganese), hijiki (with detoxifying effects), arame (supporting hormonal balance), kombu and kelp (regulating blood pressure and kidney function), nori (the most protein-rich), and wakame (with the highest calcium content).

Beyond their nutritional value, macroalgae have played a pivotal role across diverse fields from antiquity to the present day. Historically, they were employed as organic fertilizers to enrich soil composition, as thermal insulation materials in construction, as a source of essential minerals—including salt—and in their calcined form as a critical raw material for glassmaking. In contemporary contexts, bioactive compounds extracted from seaweed—such as alginates, agar, and carrageenan—serve as foundational components in advanced manufacturing processes. These substances function as rheology modifiers in food production, stabilizers in pharmaceutical formulations, and emulsifiers in premium cosmetic products. Their distinctive physicochemical properties render them indispensable across multiple industrial sectors.