15 Impressive Benefits of Seaweed

by Meenakshi Nagdeve last updated -

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The health benefits of seaweed include its ability to manage obesity, diabetes, influenza, and radiation poisoning. It helps in improving digestive health, dental health, cardiovascular health, and maintaining healthy skin and hair. It protects eyes and has anti-coagulant properties. It also covers the body’s need for iodine and helps in detoxification.

What is Seaweed?

Seaweed is a general nomenclature used for a number of species of algae and marine plants that breed in varied water bodies like rivers and oceans. They grow in a wide range of sizes from minuscule to gigantic. Most of the seaweeds are medium-sized and are available in multiple colors like red, brown, and green. They can be spotted ubiquitously on the seashores or coastlines.

Microscopic seaweed like phytoplankton grows hanging in the water. Bigger ones like giant kelp, which is one of the largest plants in the world, grow enormously and stand like an underwater tree with its roots at the foot of the sea. Unlike a weed that grows liberally and can be harmful to the area it dwells in, it plays an extremely vital role in the marine life. It serves as a foundation for the majority of the food chains and provides a home to a number of marine creatures. In addition to this, seaweed possesses anti-microbial and anti-inflammatory properties that have been trusted for providing health benefits to humans from ancient times.

A bowl of stir-fried wakame seaweed on a wooden mat

Nutrition Facts

Seaweed, agar, raw
Serving Size :
Water [g]91.32
Energy [kcal]26
Protein [g]0.54
Total lipid (fat) [g]0.03
Carbohydrate, by difference [g]6.75
Fiber, total dietary [g]0.5
Sugars, total [g]0.28
Calcium, Ca [mg]54
Iron, Fe [mg]1.86
Magnesium, Mg [mg]67
Phosphorus, P [mg]5
Potassium, K [mg]226
Sodium, Na [mg]9
Zinc, Zn [mg]0.58
Vitamin C, total ascorbic acid [mg]0
Thiamin [mg]0.01
Riboflavin [mg]0.02
Niacin [mg]0.06
Vitamin B-6 [mg]0.03
Folate, DFE [µg]85
Vitamin B-12 [µg]0
Vitamin A, RAE [µg]0
Vitamin A, IU [IU]0
Vitamin E (alpha-tocopherol) [mg]0.87
Vitamin D (D2 + D3) [µg]0
Vitamin D [IU]0
Vitamin K (phylloquinone) [µg]2.3
Fatty acids, total saturated [g]0.01
Fatty acids, total monounsaturated [g]0
Fatty acids, total polyunsaturated [g]0.01
Fatty acids, total trans [g]0
Cholesterol [mg]0
Caffeine [mg]0
Sources include : USDA

Nutritional Value of Seaweed

Seaweed contains a massive variety of health-promoting components as compared to the majority of other plant and animal-based foods available on land. It is a rich source of essential minerals such as magnesium, calcium, copper, potassium, selenium, zinc, iodine, and iron. It is also very low in fats. It is also a treasure trove of antioxidants, phytonutrients and rich fiber content that is required by the body. Vitamins present in seaweed are vitamin A, B, C, E, and vitamin K. It also contains omega-3 fatty acids and all the vital amino acids necessary for the body.

Health Benefits of Seaweed

Seaweed offers many health benefits that have been detailed below.

Source of Iodine

Seaweed is a rich source of iodine, which it absorbs in ample amounts from the sea water. Iodine is a vital nutrient required for proper growth for all age groups. It is essential for the normal regulation of thyroid function, which also involves the brain and pituitary gland. The thyroid hormone plays an essential role in the process of myelination of the central nervous system in newborns. A deficiency of iodine in the body can result in abnormalities such as thyroid enlargement or goiter, hypothyroidism, and intellectual disability, formerly known as mental retardation. Iodine is extremely crucial in pregnancy and breastfeeding for the normal development of the brain cells of the baby. Deficiency during these periods or early childhood can lead to weak intellectual growth and abnormal development of the brain.

Prevents Obesity

Scientific research has shown that edible seaweed possesses anti-obesity effects. The compound fucoxanthin present in it helps in reducing the accumulation of fats and aids in weight loss. Due to its ability to promote the oxidation of fats, it is used in making prescription diet pills and gastric banding pills. These pills should always be considered after consultation with a medical professional.

Aids in Digestion

Seaweed has a mild laxative effect and is quite useful in maintaining healthy digestion. It aids in stimulating the release of digestive enzymes, supporting the absorption of nutrients, and facilitating the metabolism of fats. Studies have shown that polysaccharides exert prebiotic effects on the gut, which helps in normal functioning of beneficial stomach bacteria and shields the stomach wall against harmful bacteria.


The fucoxanthin compound present in brown algae has been proven effective in exerting anti-diabetic effects. Along with this, the triglyceride absorption of seaweed Laminaria japonica, also known as kombu, has been praised for its effect on diabetes. According to one research, the anti-diabetic effect can be attributed to the presence of alginic acid in the seaweed kombu.

Dental Care

Seaweed extracts have long been appreciated for their preventative effect in the growth of dental cavities. The anti-inflammatory properties are responsible for the improvement in the functioning of salivary glands and making the oral tissues more resistant to damage. Alginate, a salt of alginic acid extracted from seaweed, is quite useful in the fabrication of dental molds.

Anti-coagulant Properties

Laboratory research has made it evident that seaweed possesses antioxidant and anti-coagulant properties. Anti-coagulants, also known as blood thinners, prevent the formation of blood clots and decrease the threat of stroke, cardiac failure, and obstruction in the veins and arteries. The polysaccharides called fucoidans, which are present in brown algae, such as Turbinaria ornate, kelp, and bladderwrack, exert this beneficial effect.

Detoxifies the Body

Seaweed possesses the ability to detoxify and cleanse the body and facilitates the excretion of toxic waste. The binding property of the natural absorbent, alginate, which is present in it, makes toxic materials, including heavy metals like lead, mercury, and other pollutants indigestible and eliminates them from the body through bowel movements.

Prevents Influenza

Seaweed possesses anti-viral properties that have been proven promising in providing a protective effect against influenza B virus. Its extracts obstruct the absorption of harmful viral particles in the cells and prevent the body from getting infected.

Protects Heart Health

Seaweed has been useful in sustaining lower levels of triglycerides and cholesterol in the body. This helps in maintaining a healthy heart, increasing circulation in the blood vessels, and preventing fatal conditions like heart failure, atherosclerosis, and peripheral artery ailments.

Inhibits Radioactive Damage

Seaweed has the ability to protect the skin from damage caused by exposure to ultraviolet B radiation from sunlight. This defensive effect can be attributed to the presence of fucoxanthin in it, which aids in preventing cell damage and enhancing the survival rate of the pre-treated cells. The antioxidant effect of fucoxanthin protects the skin from photo-aging, pigmentation, and wrinkle formation, while also making it an effective component to be used in the cosmetic industry for the manufacturing of sunscreens. Various research studies conducted to investigate the radioprotective effect of seaweed extracts against the exposure to gamma radiations have shown positive results.

Eye Care

The anti-ocular inflammatory effect exerted by fucoxanthin, present in seaweed, has shown promising results in the prevention of after-cataract. This complication is also known as posterior capsule opacification, which can occur after cataract surgery. Fucoxanthin is utilized in the formulation of products used in ocular implants in the cataract surgery to avoid the risk of after-cataract.

Skin Care

The wealth of essential vitamins, minerals, amino acids, and antioxidants in seaweed helps in keeping the skin revitalized, moisturized, and youthful. These elements guard the skin against the harmful effects of environmental pollutants and help slow down the skin’s aging process. Scientific research has made it evident that seaweed extracts contain anti-aging properties and are a useful ingredient in the manufacturing of skin care cosmetics. The anti-inflammatory properties present in seaweed are useful in treating skin rashes and wounds. The phytonutrients elevate blood flow and bring a healthy glow to the face. Seaweed wraps detoxify and cleanse the skin by expelling toxins out of the pores. Seaweed baths have also been admired among British and Irish for ages due to their therapeutic effects.

Hair Care

The high mineral content of seaweed also aids in maintaining healthy hair. Minerals help in strengthening the roots and shafts of hair follicles and make them thick and lustrous. Due to this beneficial effect, seaweed has been proven valuable in the manufacturing of shampoos and hair creams.

Other Benefits

Seaweed helps in maintaining the electrolyte balance of the body. The anti-inflammatory effect has proven effective in the treatment of osteoporosis and rheumatoid arthritis as well. They possess healing properties that aid in enriched blood circulation and a robust immune system.

Uses of Seaweed

Culinary Uses

Seaweeds have a nice flavor and is served as a delicacy in many Asian countries such as Japan, China, and Korea. Nori, kombu, and wakame are some of the most commonly grown and used species in these countries. Famous Japanese sushi roll uses seaweed called nori as an ingredient in rice and raw fish. Seaweed such as agars and carrageenans are used in many processed food items like yogurt, health drinks, non-vegetarian dishes, and even high-quality German beer. The harvesting of seaweed is done to extract phycocolloids such as agar, carrageenan, and alginate to use them as food additives or preservatives for fish, meat dishes, and baked items.

Other Uses

Manufacturing Usage: Seaweed is a good emulsifier and possesses good water holding, oil holding, gelling, and binding properties, which make it quite useful in food and industrial applications. It is used as a binding agent in making jellies, gels, adhesives, paints, and dental creams. Seaweed is also used as a softening agent in the cosmetic industry for making organic skin care products.

Plant Growth: Seaweed also provides a range of benefits favorable for the growth of plants. They aid in the formation of roots, provide better resistance, and enhance the yield and shelf life of harvested crops. They are used in the manufacturing of fertilizers and soil conditioners.

Wastewater Treatment: Seaweed can also be utilized in the treatment of wastewater. They have been quite effective in the treatment of agricultural waste and sewage to lower the toxic content of water such as nitrogen and phosphorous before the water reaches the rivers or lakes. They also help get rid of the toxic metals from the waste released by those industries.

Fish and Cattle Feed: Seaweed is considered a good option for feeding fish and cattle that dwell in coastal areas.

It offers an immense range of health benefits and is appreciated for its distinct flavor. However, there are a few side effects which should be taken into consideration when including it in your diet.

Side Effects of Seaweed

Excess Iodine: The consumption of excess seaweed may increase the quantity of iodine above acceptable levels. This can raise the levels of thyroid-stimulating hormone, which can cause serious conditions like thyroid and goiter. These conditions can heighten the risk of thyroid cancer. Certain cases of iodine-induced thyrotoxicosis have also been reported after the consumption of iodine-rich seaweed when suffering from a thyroid complication. Medical professionals advise the people with underlying thyroid conditions to avoid medication containing iodine, as their bodies might fail to adapt to excessive iodine content.

As per the guidelines set by the Food and Nutrition Board, the daily requirement of iodine for adults is 150 mcg per day and the tolerable upper limit is 1100 mcg/day. For infants and other younger groups, it is proportionately lower.

Heavy Metals and Other Chemicals: Seaweed also contains some concentration of heavy metals and chemicals like mercury, cadmium, lead, and arsenic which can be poisonous. Significant consumption of these heavy metals present in it can lead to medical complications like cancer, brain damage, gastrointestinal problems, and kidney diseases. In addition to this, people who need to limit their intake of salt because of certain health conditions should watch out for the sodium content in seaweed. It is advised that people should cautiously choose the quantity and variety of this type of plant to be included in the diet.

Pregnancy and Lactation: The surgical application of extracts of the seaweed Laminaria during childbirth is not considered safe. Laminaria alters the hormones and may result in fatal infections or other serious conditions in both mothers and babies.

Drug Interaction: Seaweed can interact with certain drugs like anti-thyroid and anticoagulants, which may lead to various medical complications. The intake of iodine while undergoing treatment for overactive thyroid can lead to abnormal functioning of thyroid gland. Certain drugs like aspirin and warfarin, which are used as anti-coagulants to slow the clotting of blood, might be interfered with due to the blood-thinning effect of seaweed. Laboratory research has shown that slimming supplements containing Fucus vesiculosus, a seaweed used to combat obesity, might compromise the medicinal effect of the amiodarone drug. In case of any ongoing medical treatment or medication, it is always advisable to consult a medical professional regarding the intake of dietary seaweed.

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About the Author

Meenakshi Nagdeve, Co-Founder, Organic Facts is a health and wellness enthusiast and is responsible for managing it. She has completed the Nutrition And Healthy Living Cornell Certificate Program, Cornell University, US. She holds a Post Graduate Diploma in Management from IIM Bangalore and B. Tech in Metallurgical Engineering and Materials Science from IIT Bombay. Prior to this, she worked for a few years in IT and Financial services. An ardent follower of naturopathy, she believes in healing with foods. In her free time, she loves to travel and taste different types of teas.

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