Seaweed, often referred to as “sea lettuce,” is not merely the green matter you spot floating in the ocean—it’s also a viable part of your dietary choices. In fact, seaweed has been a part of human cuisine since ancient times, dating back to the 4th century in Japan and the 6th century in China. These days, Japan, China, and the Republic of Korea are the top three countries where seaweed is a staple in the diet. Furthermore, its popularity is on the rise in various other countries worldwide, including the United States, where it’s often consumed as a roasted seaweed snack.
Seaweed can have a distinctly salty taste, which may require some adjustment if you’re considering trying it for the first time. However, if the notion of consuming this marine leafy green seems unconventional, it’s worth exploring the potential effects, both positive and negative, it can have on your body. To gain deeper insights, we consulted nutrition experts to provide us with a better understanding of the surprising impacts of incorporating seaweed into your diet.
1) You’ll get plenty of iodine
Seaweed is a notable source of an essential mineral: iodine. Just 2 tablespoons of dried nori, for example, provide a significant 77% of your daily value of iodine. Iodine plays a pivotal role in the function of thyroid hormones, which, in turn, regulate crucial biological processes like metabolism.
While iodine can also be obtained from foods like fish, yogurt, oysters, milk, iodine-enriched bread, and iodized table salt, seaweed offers a flavorful alternative.
Sarah Anzlovar, MS, RDN, LDN, the owner of Sarah Gold Nutrition, a virtual private practice located outside of Boston, MA, notes, “Seaweed can be beneficial for individuals who don’t consume much iodized table salt, seafood, or dairy.”
However, it’s essential to be discerning about the type of seaweed you choose to incorporate into your diet, as there are various varieties available.
“Some forms of seaweed can contain exceptionally high levels of iodine,” warns Mitri. “Overindulging in these varieties can lead to thyroid issues, such as neck swelling and weight gain.”
Anzlovar adds, “Excessive iodine intake, even from food, can contribute to thyroid problems or worsen existing hypothyroidism. The iodine content varies by seaweed type, but consuming one cup of most seaweed provides your daily requirement. Kelp, dulse, and kombu are on the higher end of the iodine scale, so it’s essential to monitor your consumption, as more isn’t necessarily better.”
2) You get a boost of important nutrients
“Seaweed is essentially vegetables of the sea,” explains Anzlovar, “and it contains a number of essential vitamins and minerals including vitamin C, calcium, potassium, folate, thiamine, riboflavin, copper, iron, iodine, and magnesium.”
Not only that, but Melissa Mitri, MS, RD, founder of Melissa Mitri Nutrition also says that seaweed has the unique ability to absorb and store minerals in concentrated amounts.
“While these minerals are essential in our diet, seaweed can sometimes contain large amounts of toxic heavy metals like cadmium, mercury, and lead,” says Mitri. “This is only a potential concern if you eat seaweed very regularly.”
Mitri suggests that if you do consume seaweed often, choose organic seaweed if possible. Typically, organic seaweed contains fewer heavy metals.
3) It may improve gut health
Incorporating seaweed into your diet can be a valuable step toward enhancing your gut health.
According to Mitri, “Seaweed is abundant in fiber and contains polysaccharides, which are sugars that promote gut health and stimulate the growth of beneficial gut bacteria. These sugars play a role in producing short-chain fatty acids, which serve as nourishment for healthy gut bacteria, facilitating their growth and flourishing.”
4) You could reduce your risk of heart disease
Consuming seaweed has been associated with potential health benefits, including a lowered cholesterol level and a reduced risk of coronary heart disease, as noted by Anzlovar.
In a journal article published in Nutrition Reviews, it was highlighted that seaweed consumption could play a significant role in modifying the impact of chronic diseases, such as cardiovascular disease (CVD), and mitigating related risk factors.
The review discussed a collaborative cohort study that indicated Japan’s lower mortality risk, which is believed to be attributed to seaweed consumption. The study suggested that the traditional Japanese dietary pattern, which includes the consumption of seaweed, is linked to a decreased risk of CVD. This underscores the potential cardiovascular benefits associated with incorporating seaweed into your diet.