Benefits, Risks and Side Effects of Seaweed Salad

Benefits, Risks and Side Effects of Seaweed Salad
March 27, 2015 9:42 PM

Seaweed salad, which is also known as hiyashiwakame and gomawakame, is one of the most popular salads sold in most of the Japanese restaurant and sushi bars. It is also used as an appetizer and as a garnish. You can incorporate seaweed into your diet in different ways like eating it plain, season it as a snack and you can also add it to your meals as a side dish. Although it is quire nutritious on its own, but the final nutrition value depends on the ingredients you add in it as well.

Its richness in nutrients and natural goodness is what makes it the top priority of health conscious people around the world. Before we can move further to discuss the health benefits and side effects of this delicious salads, let’s move on to discuss some basics here.

What is seaweed

Seaweed is a macroscopic, marine algae, which includes red, brown and green algae. These algae are abundantly found near the sea bed and most of the times seaweed is found attached to the rocks. You might be amazed to know, but seaweed has secured the position of being the top source of nutrients even for our ancestors. Seaweed is being used in China for thousands of years. Think of seaweed as a “super food” as it is loaded with the natural ingredients that your body needs. Seaweed is the perfect combination of much needed vitamins and minerals. As much as 34% of the dry weight of seaweed is made of iodine, magnesium, vitamin A and C, EPA, alpha linoleic acid protein, iron and calcium.  The qualities and nutrient content varies with different types of seaweed. Here are different types of seaweed that you should know about.

Green seaweed

Green seaweed is also known as chlorella. This weed is marketed as a supplement for cancer preventions, weight control, and also for boosting the immune system. All these qualities of green seaweed are perhaps due to its rich nutrient values. When dried, it contains 45% protein, 20 % fats, 20% carbohydrate, 5% fiber and remaining 10% forms minerals and vitamins.

Among different vitamins, it is extremely abundant in folate and vitamin B complex. Due to these vitamins it is especially valuable for pregnant females, in anemia patients and patients with hypertensive disorders.

Anemia during pregnancy is extremely common. A significant proportion of pregnant females suffer from anemia while they’re pregnant. This can have adverse outcomes both for the mother and the fetus. Seaweed, being rich in folate and iron, may be a valuable option for treating anemia related with pregnancy. In fact this has been proved by clinical trials as well. The results of a study showed that use of green seaweed helped correct anemia of as much as 70% users. Moreover, it also helps correct the edema and hypertension related with pregnancy conditions.

Human body is a highly system in which thousands of chemical processed take place per second. Just like a factory produces a lot of wastes, human body produces a lot of toxins as well. Anti-oxidants are natural substances that help detoxify body systems. Green seaweed is one such food that contains a lot of anti-oxidants that can help the body get rid of toxins. This is particularly helpful for our brain and can aid in reducing age related decline in cognition. Animals suffering from Alzheimer’s disease were fed on chlorella and its effects on the levels of oxidative stress and cognition were observed. It was concluded that chlorella was helpful in reducing oxidative stress and can also helped boost cognitive functions as well.

It is also helpful for people having diabetes. A study conducted on 17 diabetic persons showed that chlorella intake helped those subjects in body fat reduction, maintenance of cholesterol level, and also helped to maintain fasting blood sugar level (1).

In a nut shell, it also aids in the treatment of a number of other conditions such as high blood pressure, different kinds of cancer, constipation, fibromyalgia syndrome, bad breath and cold (2, 3). Diarrhea, gas, green discoloration of stool, stomach cramping and nausea are some of some side effects that may follow the use of chlorella. In addition, green seaweed may also result in increased sensitivity of skin to the sunlight and other skin allergies.

Red seaweed (red algae)

Prophyra and chondrus are two red seaweeds used as important food items in China and Japan. Red seaweed is also widely used in pharmaceutical industries. Red seaweed is less viscous and have shear stress. If their shear stress is removed you can use it in similar way as you use ketchup. If you want to use it as a ketchup, shake it and make it thin, otherwise, it will settle and will become thick. However as red seaweeds contain carrageenan, which has been connected to some health problems, such as gut inflammation (7) you should not consume it without prior consent of your physician. 

Brown seaweed

Brown seaweed is popularly known as wakame. In America, it became a hit in 1960s and after that it became a popular selling item in the Asian –American grocery stores. With slippery texture and sweet taste, wakame leaves can be cut into small pieces and can be used in cooking. While cooking, leaves usually expand. It is available in different forms; it may be salted, or dried. Miso soup and tofu salad are the most famous dishes made out of wakame. In sushi restaurants of American, wakame is used in making some very popular dishes called GomaWakame and seaweed salad.

Like other seaweeds, wakame is also rich in nutritious ingredients and gives a lot of benefits to health. It is rich in eicosapentaenoic acid (EPA), something similar to Omega -3 acid. It also contains magnesium and zinc. Wakame is used in many soups and salads .Wakame soup contains an element called Fucoxanthin, which is proven to be effective in weight loss. Fucoxanthin is only found in brown seaweed and is absent in green and red seaweed. Japanese miso soup replaces brown seaweed with green seaweed (4).

Another famous brown seaweed known as Bladderwrack is found in the coasts of the North Sea. Bladderwrack contains fucoidan, which is helpful in lessening the thickness of skin and also increases the elasticity of the skin. Due to these properties, bladderwrack is used in the preparation of anti-aging gels. Bladderwrack may also be helpful in the treatment of diabetes, cancer, and some other skin diseases. These facts are just in the initial stages and more scientific data is needed to back these claims. You’ve to be cautious about the amount of brown seaweed you consume on daily basis. It is extremely beneficial for a healthy lifestyle as long as you’re consuming only a small amount of this weed.

You may experience some side effects if you intend to use higher amount. High doses of bladderwrack can lead to several side effects, some of which can be really serious. On such side effect is the hypo-functioning of thyroid gland and it can even trigger the progression of thyroid cancer.

Ingredients in Seaweed Salad

Most commonly used seaweed in seaweed salad is Wakame (Brown seaweed). It is commonly sesame flavored. Cloud ear mushrooms, red pepper flakes and vinegar are some other seasoning components used in making seaweed salad.

Agar, a gelatin made from seaweed, is also used for giving texture. Depending on the manufacturer, different dyes, sugar, apple, garlic, scallions, cilantro, ginger, soy sauce, and corn syrup are also added to give different colors and flavors to the salad. All these ingredients, along with seaweed, make a very healthy recipe. For instance, ginger assists your digestive system and garlic boosts your immune system.

Nutrients in pre-packaged seaweed salad

There are 70 calories, 10 grams of carbohydrates, 50 milligrams of calcium, 4 gram of fat and 1 grams of protein in this salad. Eating this salad is a healthy option that you’ve as you can get a lot of nutrients without overloading your system with extra calories.

Health benefits of seaweed salad

Weight control

The recipe of weight loss is quite simple. You need to eat less calories and burn more of them. That is going to happen if you don’t overload your system by eating extra calories from the food. If you want to lose fat then seaweed salad is the best you’ve. Here is the reason why! First, it contains minimal amount of calories i.e. as much as 106 calories per serving and compared to side dishes like baked beans that contain 392 calories and cooked rice having 242 calories per cup. Second, it is extremely rich all the healthy nutrients that boost the metabolism and aid in the speedy breakdown of calories and don’t let them get stored as fat.

Goodness of nutrients in seaweed salad

Wakame is usually used in making seaweed salad. Calcium, vitamin K, magnesium, ligans, riboflavin and folate are some important nutrients in this salad, each play a specific role in maintaining health. Here is the detail of the nutrients present in seaweed salad and their effects on health.

Vitamin K

Vitamin K is a fat soluble nutrient, which is found in abundance in seaweed. Vitamin K works together with platelets that help to clot blood following any injury. When you get some injury, vitamin K sends a signal to platelets to aggregate around the injury spot and form a clot, so that further bleeding form wound could stop. Recommended daily intake of Vitamin K is 90 microgram for women and 120 micro gram for men. One cup of seaweed can give you 29-22 percent of daily recommended need of Vitamin K. The amount of vitamin K in seaweed can vary from type to type, like Spirulina contains more vitamin K (it contains 1.8 micrograms vitamin K per tablespoon), whereas Wakame contains less vitamin K as compared to Spirulina (it contains 2.1 micrograms vitamin K per cup).


Calcium is also an important content of seaweed, so if you’re eating seaweed salad, you’re making sure that you’re eating enough calcium. It is an essential mineral vital for your teeth and bones, so most of calcium you take goes to your bones and teeth. A small amount of calcium also contributes in the contraction of the muscles and also aids in the nervous system communication. 60 milligrams of both kelp and wakame contain 6 percent of the recommended daily intake of calcium.


For our day to day activities we need energy and that energy comes from iron from our diet. What makes iron so important? Iron, as we all know, is an important ingredient of our blood cells so if you are diet is rich in iron, it would nourish our circulatory system. Low iron level in your blood would lead you to anemia, where anemia is a condition in which patient turns pale in color and develops shortness of breath. A cup of kelp and wakame gives you 1.1 and 0.8 milligrams of iron respectively. Whereas, one tablespoon of Spirulina gives your body 2 milligrams of iron. All the iron in seaweed is especially very helpful for pregnant females as they’re more likely to suffer from iron deficiency. In fact, this fact has been proved by clinical experiments as well where the use of seaweed helped as much as 70% pregnant females regain their iron stores.


Riboflavin works together with fats, carbohydrates and protein. The role of riboflavin is pivotal for other vitamins as well and adequate amount of riboflavin is necessary for the activation of other vitamins. It also aids in the production of red blood cells. Most importantly, it is an essential anti-oxidant. It works with other anti-oxidants like asniacin, folate and vitamin B6 to detoxify body systems.


Folate is essential on daily basis, its importance exceeds even more if you’re a pregnant lady. Generally, it aids in the formation of red blood cells. In addition, it is also helpful in the prevention of several developmental defects in your fetus if you’re a pregnant lady.


Studies prove that lignans play a vital role in protection against breast cancer (5).


Magnesium helps our muscles in contraction and relaxation. Magnesium also takes part in transportation of energy and enzyme across and within the cells where it also facilitates in protein production.


Iodine is critical for the effective functioning of the body metabolism. It is because an adequate supply of iodine is necessary for the proper production of thyroid hormone that aid in energy production.

Burns fats

A study published in Biochemical and Biophysical research communication in 2005 proved that the seaweed salad with wakame in it contains fucoxanthin (6). Clinical studies have shown that seaweed can decrease the fat content of the body by 10 percent. It acts by increasing the metabolic rate of the body. When the rate of metabolism of body increases, it burns more calories coming from fats.

Fat blocking effect

Eating seaweed salad also enhance your ability to decrease the absorption of fat from the gut. Fiber in seaweed blocks more than 75% fat uptake as compared to same amount of any other food you are eating .According to some source, (although this is not scientifically proven), fiber in seaweed called as alginate would help your body stop the absorption and break down of dietary fats. Alginate fibers in seaweed block fat absorption more effectively. Some estimates suggest that it is 60 times more potent in reducing the absorption of fats and compared to other forms of dietary fibers and similar weight control ingredients. All these effects of seaweed are based on preliminary research. So, more research is needed in this area to see the effects of seaweed on weight control and obesity. Therefore, you must consult with your healthcare provide before starting with the use of seaweed or related products for weight control.

Boosts immune system

Other ingredients in seaweed salad like garlic give several added benefits in terms of uplifting your health development. Garlic is being used as a medicine since pre-historic times. It has been an essential component of several folk remedies meant for curing countless disease. Modern studies now prove that garlic improves the immune system. An article was published in the Journal of the National Medical association, which was named “Garlic Revisited”. This article stated that garlic aids a great deal in in improving the functioning of our immune system. In addition, it limits inflammation due to its anti-inflammatory effects. Similarly, it helps a great deal in eliminating the toxins from body and also assists in lowering oxidative stress that it usually secondary to the buildup of toxins in the body.

Aids in digestion

Another seaweed salad ingredient is ginger and it is also used as a medicine in traditional Asian medicines while dealing with issues related to stomach and digestion. It is a very popular ingredient of Asian cuisines. The reason for using it so regularly is its ability to aid in proper digestion of food and decreasing the chances of gut issues like diarrhea, constipation and excessive bloating. According to study done in the university of Maryland and Medical center, ginger is useful in treating the problems related to stomach, especially for women and other people who suffer from nausea and vomiting during pregnancy and chemotherapy.

Reduce chronic disease risk

Another important ingredient that is usually added in most of the recipes of seaweed salad is apple .Phytochemicals are important chemicals, which are found in high concentration in apple. This chemical proved were beneficiary for human health. In 2004, the department of Food Science at Cornell University published a paper that eating apple on regular basis can greatly decrease the risk of chronic diseases. In addition, its vital nutrients also help in reducing the risk of age related decline in body functions such as cognition. For instance, apple is also helpful in decreasing the risk of age related cognitive decline as seen in Alzheimer’s disease and dementia.

Side effects of seaweed salad

Watch sodium

There is 691 milligrams of sodium in a standard serving bowl of seaweed salad, which forms 29 percent of daily recommended intake of sodium. If you are using soy sauce in you seaweed salad then you’re adding more sodium in it as soy sauce is itself very rich in sodium. According to the 2010 Dietary Guidelines for Americans, an average individual must reduce the use of sodium in order to lessen the risk of high blood pressure and cardiovascular disease. Low sodium soy-sauce would be a good alternative or using a small amount of soy-sauce.

Gastrointestinal issues

Seaweed is a double edged sword when it comes to the health of gastrointestinal system. Eating seaweed in moderation can be a boon for your gastrointestinal system, thanks to the high fiber content of this diet. However, things take a rather drastic turn if you eat a lot of seaweed. Fiber helps loosen stool and aids in the speedy movement of food through your gut. But, when taken in excess, it can cause gut hyper-activity and may induce side effects like diarrhea and bloating. A research included several participants were given seaweed for weight loss. But, it was seen that most of the participants dropped out from the study due to the exaggerated side effects of the gut to higher intake of seaweed.

Iodine toxicity

Iodine is an essential nutrient for the proper functioning of thyroid, which is one of the most important glands in human body. A small amount of iodine should be supplied to the thyroid gland on daily basis to keep it up and running. Seaweed, due to its rich iodine supply, can help with the proper functioning of thyroid- at last hen it is used in a small amount. When taken in excess, the body goes into a state of iodine overload and the functioning of thyroid actually decreases instead of increasing. Therefore, be careful about the use of seaweed if you have some thyroid condition. In fact, there have been some reports that link the excessive use of seaweed and its related products with higher incidence of thyroid cancer. So, do consult with your healthcare provider before starting with seaweed powder if you’re already suffering from some condition of the thyroid.

Heavy metals

As seaweed grows in sea, there are chances that the product you’re using may be polluted with dangerous heavy metals.

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Written by: Michal Vilímovský (EN)
Education: Medical student, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic
Article resources: Pubmed - see references within the article
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Published: March 27, 2015 9:42 PM
Last updated: April 10, 2015 1:55 PM
Next scheduled update: April 10, 2017 1:55 PM
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