7 Amazing Health Advantages of Seaweed

Sea vegetables or seaweed is a type of algae growing in the sea. They are a source of food for organisms that live in the ocean and have different colors that vary from red and green to black and brown. Seaweed is found along the shorelines across the world, but they are most commonly eaten in Japan, China and Korea.

It’s a versatile food and can be used in various dishes like soups, stews, sushi, salads and smoothies.

Moreover, it’s extremely healthy and nutritious, so having even a little of it is going to be great. Some benefits of having seaweed are discussed below:

Contains Iodine and Tyrosine that Support Thyroid Function

Thyroid gland releases hormones to control growth, produce energy, help in reproduction,[1] and repair damaged body cells.[2] Thyroid depends on iodine for producing hormones. When enough iodine is not available, symptoms like changes in weight, swelling of the neck may be experienced.[3]


The prescribed intake of iodine is 150 mcg in a day.[4] Seaweed can absorb iodine from the ocean.[5] The content of iodine in seaweed depends on how it was processed and where it was grown. Kelp, a type of seaweed, is a great source of iodine.

Seaweed is also rich in amino acid, called tyrosine, which works in conjunction with iodine to help the thyroid gland do its function effectively.

Great Source of Vitamins and Minerals

Adding seaweed in your diet not only enhances the taste and flavor, but also boosts your intake of minerals and vitamins. Seaweed also contains vitamin C, A, K and E along with folate, zinc, calcium and sodium.

The proteins present in seaweed like spirulina and chlorella are wonderful source of essential amino acids. So, when you have seaweed, you get a wide range of amino acids.

Seaweed also have vitamin B12 and omega 3 fats.[6] However, it is still controversial whether your body is able to fully absorb the vitamin B12 from seaweed.[7]

Contains Antioxidants

Antioxidants help reduce the reactivity of unstable molecules, called free radicals.[8] This prevents damage to the cells. Production of free radicals is known to cause many problems of the heart and other chronic diseases like diabetes.[9]

Apart from the vitamins it contains, seaweed also has a number of beneficial plant-based compounds like flavonoids and carotenoids. These protect the body from damage caused due to free radicals.

An important carotenoid, known as fucoxanthin is present in brown algae and it is 13 times more effective than the vitamin E in terms of antioxidant properties. This compound protects cell membranes better than vitamin A. Its absorption may be enhanced by having fat alongside fucoxanthin.

Gives Fiber and Polysaccharides That Boost The Heath of The Gut

There is a big role of gut bacteria in health. The number of bacteria cells is more than human cells in the body. Imbalance of good and bad bacteria can cause disease and sickness.[10]

Seaweed has fiber, which promotes the health of the gut.[11] The fiber content in seaweed is 25 to 75%, which is more than most vegetables and fruits.[12]

Fiber can be a source of food for bacteria in the large intestine. Further there are some sugars present in seaweed which increase the development of good gut bacteria. The polysaccharides increase the production of fatty acids which nourish the gut.

Help in Weight Loss by Delaying Hunger

Seaweed practically has no calories, but has a lot of fiber.[13] This helps you feel fuller for longer duration and also curbs your hunger pangs. Thus, seaweed helps prevent obesity.


Also, the compound, fucoxanthin may help reduce body fat. In a study on animal models, it was found that rats, who consumed fucoxanthin lost weight as compared to the control group that did not.

Besides, fucoxanthin is found to reduce blood sugar levels in rats, which further results in weight loss.[14] The studies on humans must however be conducted to verify the results.

Helps Reduce Risk of Heart Disease

Heart diseases are the leading cause of death worldwide. Some factors that cause heart diseases are high cholesterol and high BP. Seaweed helps reduce the levels of cholesterol.

An eight-week study was conducted on rats in which, they were fed high cholesterol and a high fat diet along with some seaweeds.[15] It was found that the cholesterol levels in fat were less by 40% and bad cholesterol by 36% along with 31% decrease in the levels of triglycerides. Heart diseases may even be caused by blood clotting. Seaweeds have carbs called fucans, which prevent blood clotting.

One study even found that fucans are as effective in clotting blood as any anti-clotting drug.[16] Research also suggests that there are peptides in seaweed, which help decrease blood pressure. However, human studies are needed before arriving at any conclusion.

Helps Reduce Risk of Diabetes by Managing Blood Sugar Levels

Diabetes is a major global health concern. It happens when the body is not able to balance blood sugar levels.

An eight-week study on 60 people in Japan found that fucoxanthin present in brown seaweed may help improve blood sugar control.[17] In this study, participants took seaweed oil that contained zero to 2 mg fucoxanthin. It was found that those, who received 2 mg fucoxanthin, had improved and better sugar levels as compared to those, who did not receive any fucoxanthin.

The study also examined blood sugar levels in people, who were genetically predisposed to insulin resistance, which comes together with type 2 diabetes. Also, a different substance, called alginate in seaweed prevents spike of blood sugar in animals. It is believed that alginate reduces the absorption of sugar in blood.[18]

Side Effects of Seaweed

Seaweed is a very healthy food but there are some dangers associated with having too much of it.

Too Much of Iodine

Seaweed may have iodine in amounts that can be dangerous. The tolerable upper limit for consumption is considered to be 1100 mcg of iodine.[19] In Asian countries, seaweed is consumed with foods that can prevent the absorption of iodine by the thyroid glands. Such foods are termed as goitrogens.

Also, seaweed is soluble in water, so iodine content may get affected with its cooking and processing. In case of kelp, if it is boiled for 15 minutes, around 90% of the iodine in it gets lost.

Some cases have reported thyroid dysfunction with the consumption of iodine-containing kelp. Once its consumption is stopped, the function of thyroid is restored.

If your intake of iodine is too much, then it may cause symptoms like fluctuations in weight and swelling near the neck. In such cases, you must reduce your intake of iodine and speak to your doctor.

Heavy Metal Concentration

Seaweed Can Store and Absorb Minerals in larger quantities.[20] So, it is of health concern as seaweed can contain toxic metals like cadmium, lead and mercury. However, the concentration of heavy metals is below than what is permissible in most countries.

A study examined the concentration of metals in different types of seaweeds obtained from Europe and Asia. It was reported that levels of metals in about 4 gm of seaweed did not pose any health risks.

But, if you are a regular consumer of seaweed, then over time, the heavy metals may start getting accumulated in your body. If you can, purchase organic seaweed as it has lesser amounts of heavy metals.


Seaweed is quite a popular ingredient in different cuisines across the world. It is a great source of iodine, which helps in the functioning of thyroid gland. It has minerals and vitamins like vitamin K, B, iron and zinc and antioxidants that prevent damage to cells.

However, excess of iodine from seaweed can be detrimental to the functioning of thyroid. To achieve optimal health, eat this ingredient regularly, but not in larger amounts.

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