The People's Perspective on Medicine

Will Eating Seaweed Protect Your Heart?

Epidemiologists in Japan have found that eating seaweed reduces the risk of heart disease.
Japanese food, Miso soup of seaweed wakame on a bowl

Most Americans don’t eat much seaweed. However, in Japan this is a popular vegetable. Does it have health benefits?

Do Japanese People Protect Their Hearts by Eating Seaweed?

Scientists noted that seaweed contains many components that could be beneficial (American Journal of Clinical Nutrition, online Sept. 13, 2019). Vitamins, minerals, soluble fiber and plant flavonoid compounds all appear to help protect against cardiovascular disease. Other researchers have pointed to the potential of polyphenols from seaweed (Marine Drugs, July 28, 2018). However, no one had studied whether a diet rich in seaweed actually led to fewer heart attacks or strokes.

The researchers utilized data from cohort studies of more than 85,000 Japanese adults to examine the link between seaweed consumption and cardiovascular disease. Consequently, they were able to analyze data from nearly 1.5 million person-years of follow-up. During that time, the volunteers experienced more than 1,200 cases of heart disease and nearly 5,000 strokes.

The Envelope, Please: 

Both men and women who ate seaweed nearly daily had a lower likelihood of heart disease than those who ate it rarely. For men, the risk was 24 percent lower. Among women, the risk was a striking 44 percent lower. However, the scientists did not find any connection between seaweed eating habits and the risk of stroke.

Should Americans Consume Seaweed?

Some people might take this as encouragement to begin eating seaweed snacks or even taking pills containing kelp or other popular forms of seaweed. While incorporating some types of sea vegetables into the diet is probably smart, people should avoid going overboard. We have written before about the dangers of taking kelp as an iodine supplement. For some people, this can trigger an overactive thyroid gland that can be risky. Your grandmother probably warned you to embrace moderation. When it comes to eating seaweed, you should follow that good advice.

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    About the Author
    Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
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    Citations
    • Murai U et al, "Seaweed intake and risk of cardiovascular disease: the Japan Public Health Center–based Prospective (JPHC) Study." American Journal of Clinical Nutrition, online Sept. 13, 2019. https://doi.org/10.1093/ajcn/nqz231
    • Gómez-Guzmán M et al, "Potential role of seaweed polyphenols in cardiovascular-associated disorders." Marine Drugs, July 28, 2018. DOI: 10.3390/md16080250
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    A conversation started, but I’m disappointed that all “seaweed” is lumped together as a class of food. That’s like saying “eat your vegetables” and not differentiating between iceberg lettuce and broccoli. There are many different sea vegetables with widely different nutritional content. Also, as another commenter mentioned, pollution is an issue.

    Could you drill deeper into the data and give us some details of the benefits of kelp vs dulse vs kombu? With your warning in mind, what is a serving size?

    Okay, great. But where can we find clean seaweed with all our polluted waters?

    Does type of seaweed make a difference? How about Nori?

    People who are regularly willing to eat seaweed probably are very health concious. Is the improved health due to the seaweed? This would be tough to control for.

    This alarming. I started snacking on organic dried seaweed to combat acid reflux, and have become somewhat addicted to it? How much is too much?

    Afraid there’s too much pollution in water to eat seaweed.

    Each seaweed has its own attributes. Alaria or Wakame protects against cancer; Irish Moss lowers blood sugar; dulce is rich is the B vitamins and lowers stress. It pays to select seaweeds accordingly.

    * Be nice, and don't over share. View comment policy^