What Is the Difference Between Nori and Wakame Seaweed and Which Is Healthier?

Nori and wakame are types of large algae. Nori is one of the most nutritious seaweeds, but wakame also has benefits.

If you've enjoyed sushi or miso soup, you've probably eaten seaweed. Perhaps you know that seaweed is low in calories and high in nutrition. You may know that nori and wakame are two types of seaweed used in cooking. But do you know the difference between nori and wakame, and which is the healthier choice? 

Both nori and wakame are macroalgae, meaning large algae. There are many species of algae, but macroalgae are large enough to see with the naked eye. There are three kinds of macroalgae: brown, red, and green. They differ by much more than color. Nori is a type of red algae. Wakame is a brown alga, which we commonly call kelp.   

Nori is the purplish-black seaweed that you see dried in sheets and rolled in sushi rolls. When growing, it has thin reddish blades or leaves. It lives in areas of mild temperature around the world and is a traditional food for many indigenous people. Today, it is cultivated in Japan, China, and Korea. The scientific name of nori is often listed as Porphyra spp, meaning various species. Its common name is purple laver.

The plant known as wakame in Japan has many other names. Its scientific name is Undaria pinnatifida. Common names include Asian kelp and sea mustard. In Korea, it is known as miyeouk or miyok.

Wakame is native to northeastern Asia and Russia and is grown as a marine crop in Japan, China, and Korea. It has spread to many parts of the world and is considered an invasive species. In some places, its introduction has had a negative impact. In others, it's been positive or neutral.

Protein, carbohydrates, and fats are known as macronutrients because humans need them in relatively large amounts. Seaweed varies in macronutrients according to its species and when and where it is collected. Nori is one of the most nutritious seaweeds, but wakame also has benefits.

Protein. Seaweed can be up to 50% protein, with a good mix of amino acids. The protein quality is less than that found in animal products but better than plant foods grown on land. Red algae such as nori have more protein than brown algae like wakame. 

Carbohydrates. Nori is lower in carbs than wakame, but both are low enough to be considered low-carb foods. 

Fats. Seaweed is low in fat, but some species contain healthy polyunsaturated fatty acids (PUFAs), which can increase HDL cholesterol, the "good" cholesterol, and lower LDL, the "bad" cholesterol. Wakame is the winner here, having more PUFAS than other species.   

Research is ongoing into the health benefits of seaweed. Lab studies and animal studies are promising, but there haven't been many human trials. Most human studies use extracts made from seaweed, so a person eating seaweed might not get the same benefits. Still, evidence suggests that adding seaweed to your diet could result in these health benefits.    

Minerals. Seaweed efficiently removes minerals from seawater. As a result, the mineral content of seaweed is ten times the content of plants that grow on land. People who eat seaweed regularly are seldom deficient in minerals.

Iodine. Seaweed is an excellent source of iodine, which is needed for thyroid health and other metabolic functions. Iodine in some plants isn't well-absorbed, but seaweed is a reliable source.  

Vitamins. Seaweed is rich in many vitamins, but some are lost in processing. Only a few studies have looked at whether humans can absorb them. Nori is rich in vitamin B12, which humans usually get from animal sources. One study of vegan children who ate nori found normal levels of B12, suggesting that they could use the vitamin and avoid B12 deficiency. 

Fucoidan. This substance, found in brown seaweed, like wakame, may help with various health problems. In one human trial, those who took fucoidan had lower diastolic blood pressure and lower LDL cholesterol. Fucoidan also appeared to help with blood sugar control. It shows promise as a cancer fighter, but researchers say we need more human trials. 

Polyphenols. Brown seaweed contains these antioxidant compounds that may help lower blood glucose, total cholesterol, and LDL cholesterol. 

Some people may need to limit their consumption of seaweed for the following reasons. 

Heavy metals. Heavy metals like arsenic and mercury appear in seaweed just as in seafood. Arsenic is mostly a concern in a seaweed called hijiki or hiziki, not in nori or wakame. Mercury is a concern in all seaweed but especially in red varieties like nori. Pregnant women should watch their consumption of seaweed because of its mercury content. 

Iodine. It's possible to get too much iodine, especially if you're very young or very old or have existing thyroid disease. Nori is your best choice if you need to limit iodine because it has less iodine than other species. Brown seaweed is especially high in iodine.   

Salt. If you need to watch your salt intake, you should be careful with seaweed, which is typically high in salt. Nori may be a good option, as processing washes away most of its salt. 

If you have mainly experienced seaweed that has been washed up on the beach, you may object to the idea of eating it. When seaweed decomposes, it releases a sulfurous gas that can be unpleasant. Fresh seaweed has a different smell that some compare to an ocean breeze. 

Your country and its culture probably influence your feelings about eating seaweed. In China, Korea, and Japan, seaweed is an accepted staple in the kitchen. In some other countries, such as France and Norway, diners regard seaweed as a luxury food. People who eat a more western diet may complain that seaweed tastes fishy. 

Seaweed can be a valuable addition to your diet. Whether nori or wakame is healthier for you depends upon your health status.