Is Seaweed Good for You? Discover 8 Nutritional Health Benefits

Medically Reviewed on 8/18/2022

First, what is seaweed?

Seaweed is the name used for numerous species of marine algae and plants growing in the oceans, lakes, rivers, and other standing water bodies. Nutritional health benefits of seaweed include reduced obesity, decreased inflammation, improved glycemic control, and other benefits.
Seaweed is the name used for numerous species of marine algae and plants growing in the oceans, lakes, rivers, and other standing water bodies. Nutritional health benefits of seaweed include reduced obesity, decreased inflammation, improved glycemic control, and other benefits.

A popular delicacy in many parts of Asia, seaweed is a popular source of many dietary necessities. It is a source of hydrocolloids like alginate, agar, and carrageenan. Many think that the unique marine environment of seaweed produces its unique properties. 

The health-based benefits of seaweed have been widely studied. The following are some findings regarding seaweed and its benefits for the human body

Seaweed is the name used for numerous species of marine algae and plants growing in the oceans, lakes, rivers, and other standing water bodies. Some types of seaweed are small, even microscopic. This is true of phytoplankton, which can live in water columns and provide a foundation for most food chains. 

On the other hand, some types can be huge, like kelp. Kelp can grow in a forest formation and trend upward under water like redwood trees from their base at the bottom of the sea. 

However, most seaweeds are medium in size, come in colors like brown, red, black, and green, and can wash up on shore pretty much anywhere. 

For centuries, seaweed has been used traditionally used in Asian foods in Japan, China, and the Republic of Korea. As these native cultures spread around the world, they took this customary diet ingredient with them. Today, there are more countries where eating seaweed is very common. 

Most commonly, tropical countries like Malaysia and Indonesia consume fresh seaweed, with salads being a popular choice. It is common in areas like Hawaii and California, in part because of larger Japanese communities.  

In the last few years, seaweed has also become very popular in France, making it more common in European recipes, but it is still considered exotic. 

Health benefits of seaweed

Source of iodine: Iodine is a mineral that is abundant in the oceans and accumulates in seaweed. For example, different types of kelp can collect iodine deposits up to 100,000 times more than what is found in the seawater surrounding it. 

Human health necessitates iodine. It is important for the function of the thyroid, and the healthy functioning of many organ systems of the body.

It is usually not found in remarkable amounts in most foods, though.  Academic and medical sources now recognize the concentrations of iodine in seaweed to be amongst the highest known.

Source of potassium: Seaweed is salty, and the taste comes not only from sodium. It comes from a variety of other mineral salts like potassium. Increasing your dietary amount of potassium in comparison to sodium is commonly advised for optimal health. Modern diets are heavy in foods that are high in sodium and low in potassium. Seaweed, though, has more potassium than sodium. Sometimes, the potassium levels in seaweed are comparable to other foods known to be high in potassium like bananas. 

Reduction of obesity. Seaweed helps in decreasing obesity by lowering the caloric value in daily diets when compared to many other foods. Diet-related obesity and diseases related to obesity are widely occurring health problems that are seen in many developed countries. Seaweed in the diet helps to prevent weight gain. The addition of seaweed helps to make you full more quickly with fewer calories. This appetite reduction leads to decreased snacking. 

Addition of essential fatty acids. Seaweed adds vitamins and essential fatty acids like omega-3s to the diet. In a lot of cases, it adds protein and most essential amino acids. Glutamate is a nutrient that gives seaweed its “umami” taste. This is recognized as a “fifth taste” and is similar to savory.

Lipid absorption and cardiovascular disease reduction. Seaweed reduces the risk of cardiovascular disease by modifying its effects on the GI tract. It does so by:

  • interfering with lipid micelle formation 
  • mixing bile acid
  • binding cholesterol 
  • diluting lipase concentration
  • slowing down lipid absorption   

Research shows that acid in algae leads to decreases in the concentration of cholesterol. It also shows an increase in cholesterol content in fecal matter. 

Source of Vitamin B12. Seaweed is a scarce source of nonanimal Vitamin b12 with its own set of benefits. Studies theorize that seaweed vitamin b12 comes from associated microbes.

Glycemic control effects: The diluting and slowing of the properties of carbohydrases in the GI system by seaweed has a positive effect on blood glucose level regulation. Control of the digestion of starch in your diet helps to control glucose levels in the blood in type 2 diabetes. Thus, seaweed is a food that can be added to the diet to increase digestive health and nutrition in all diets. 

The addition of fucoidan: Seaweed nutritional assets do not stop with vitamins, minerals, and proteins. It contains numerous bioactive compounds that help with immune function. One of these is fucoidan, which is found in brown seaweeds like kelp, bladderwrack, and rockweed. Seaweed benefits include:

  • protection from viruses 
  • inhibiting the growth of cancer
  • the  healthy promotion of blood coagulation 
  • help regulating blood pressure
  • antioxidant properties

Good fiber: You likely know that fiber is essential to our bodies in numerous ways. It is needed for healthy digestion and bowel movements. It promotes the growth of healthy microbes and bacteria in our gut. It helps with the elimination of toxins and helps with fluctuations in blood sugar. Seaweed has soluble and insoluble fiber. The amounts may not be that large, but there are still beneficial percentages in the seaweed as a whole. A lot of fiber is in the complex polysaccharide form. This sugar form is unique to seaweed and offers additional health benefits. 

Increases probiotic action: Even though the sugary fiber found in seaweed is not digested in the upper GI tract by enzymes, it is degraded by microflora in the colon. It is complex and works with beneficial bacteria in gut lymphoid tissue. Health-promoting bacteria in this area, called probiotics and prebiotics, play a key role in nutrition and digestive health. They salvage nutrients and products of metabolism like short-chain fatty acids. Dietary regulation can be achieved using probiotic products. Fermentation of brown seaweed fiber, for instance, indicates that the probiotics it contains follow patterns exhibited by other, non-seaweed food.  This fiber promotes the growth of bacteria that is vital to healthy guts. It helps to maintain a good balance among the microflora in the colon.   

Colorectal cancer risk decrease: Colorectal cancer involves tumors of the rectum, colon, and appendix. It is the third-most-commonly-diagnosed-cancer in the world. Over half of colorectal cancer deaths occur in more technologically developed areas of the world, with studies showing that diets with large amounts of processed meat and red meat that are low in fiber create an increased risk of colorectal cancer. 

Dietary fiber is presumed to help in reducing the risk of cancer through protective mechanisms. This includes:

  • decrease in time to get feces through the bowel 
  • production of short-chain fatty acids that encourage anticarcinogenic action 
  • diluted fecal carcinogens  
  • binding of carcinogenic bile acids  

Suppresses gastrointestinal inflammation: The polysaccharide fiber in seaweed is proven to suppress inflammation in the stomach and thus reduces ulcers in gastroduodenal areas.  Many of the soluble kinds of fiber in algae help to develop a viscous layer next to the epithelial layer of the upper digestive tract. This provides a protective coating type of effect against a low-PH environment and digestive enzymes. This minimizes the chance of causing inflammation of the epithelial layer by pathogenic organisms or chemicals. Also, various seaweed dietary fiber helps to regenerate mucus membranes that were previously damaged. 

Seaweed pigments: Fucoxanthin is a pigment found in brown seaweed. Phycocyanin is found in red seaweed. Many types of seaweed also contain chlorophyll. These pigments not only give color but also have antioxidant properties. These benefits are then passed on to seaweed eaters. 

In addition to all of the nutritional benefits previously described, numerous phenolic molecules have been found in seaweed. These molecules do not act as conventional nutrients but are proven to have a type of bioactive property that is affiliated with enhancing physical health and prevention of diseases. They also have therapeutic effects on certain diseases because of nutritional content, treating obesity, cardiovascular diseases, and diabetes


According to the USDA, there is no difference between a “portion” and a “serving.” See Answer

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Medically Reviewed on 8/18/2022

Advances in Food and Nutrition Research: "Nutritional and digestive health benefits of seaweed."

Food and Agriculture Organization of the United Nations: "SEAWEEDS USED AS HUMAN FOOD."

Maine Seaweed Council: "Nutritious Seaweeds!" "Nutritional and Digestive Health Benefits of Seaweed."

National Oceanic and Atmospheric Administration: "What is seaweed?"