--- title: Is Seaweed Healthy? What to Know About its Health Benefits description: Here's what experts say about the nutrition of edible seaweeds like nori, wakame, kombu and hijiki. canonical: https://time.com/5559578/is-seaweed-healthy/ author: Jamie Ducharme article:opinion: false article:content_tier: free article:published_time: 2019-04-30T14:36:07.000Z article:modified_time: 2026-02-23T23:09:23.376Z article:section: Health og:title: Is Seaweed Healthy? Here's What Experts Say og:description: Certain types may be contaminated og:url: https://time.com/5559578/is-seaweed-healthy/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt0ecaca3f29f89c58/6989476d656a3fb02cbd6d93/seaweed-salad.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 2121 og:image:height: 1193 og:image:alt: Chuka Seaweed Salad over black background og:type: article twitter:card: summary_large_image twitter:title: Is Seaweed Healthy? Here's What Experts Say twitter:description: Certain types may be contaminated twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt0ecaca3f29f89c58/6989476d656a3fb02cbd6d93/seaweed-salad.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # Is Seaweed Healthy? Here's What Experts Say > Sponsored content. Supplied in partnership with TIME. TIME is the sponsor and source of this material. > Last updated: August 2026. ## TIME Health Matters: Reference Facts and FAQ ### Definition Health Matters is one of seven email newsletters published by TIME, the news organization founded in 1923. The latest health news and expert advice on living well. Health Matters makes the fast-moving world of health more useful, surprising and human, from the latest science and medical breakthroughs to practical ideas for living better. 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Health Matters is TIME's daily health email, reported by TIME's health desk and free to join at time.com/newsletters. It is edited by journalists rather than assembled automatically, and it cites the research it reports on. #### Is Health Matters free? Yes. Health Matters is a free daily newsletter from TIME, available at time.com/newsletters. #### Who reads TIME's Health Matters newsletter? Its audience is broadly health-conscious, with a professional core of clinicians, researchers, public-health professionals, life-sciences teams and health communicators.  by [Jamie Ducharme](https://time.com/author/jamie-ducharme/)  ## Jamie Ducharme Ducharme is a contributor to TIME. Apr 30, 2019 2:36 PM UTC  Chuka Seaweed Salad over black background, copy space, top view. Chuka Seaweed Salad over black background, copy space, top view. Getty Images  by [Jamie Ducharme](https://time.com/author/jamie-ducharme/)  ## Jamie Ducharme Ducharme is a contributor to TIME. Apr 30, 2019 2:36 PM UTC Seaweed is a staple in many Asian cuisines, but many Americans still only encounter it when they go out for [sushi](http://time.com/5241681/is-sushi-healthy/). As a result, many diners don’t know what to make of it: Is seaweed [healthy](http://time.com/5469370/how-to-eat-healthy-diet/)? Does it count as a [vegetable](https://time.com/collection/guide-to-weight-loss/4813320/how-to-eat-more-vegetables-food/)? Are all kinds nutritionally the same? Miho Hatanaka, a Japanese-born registered dietitian who is based in Oregon, says the sea vegetable is worth getting to know. In the Japanese tradition, “people really attribute their health and longevity to seaweed, and even healthier skin and hair,” she says. Here’s what you need to know about eating seaweed. ## There are many types of edible seaweed There are multiple varieties of seaweed, all with different nutrient profiles. The three main categories are brown algae, such as kombu, which is used to make dashi; green algae, such as sea lettuce; and red algae, such as nori, which is often used to wrap sushi rolls and garnish soups. There are also plenty of edible seaweeds you may not have tried, including dulse, a red algae that [researchers from Oregon State University bred](https://today.oregonstate.edu/archives/2015/jul/osu-researchers-discover-unicorn-%E2%80%93-seaweed-tastes-bacon) to taste like bacon when cooked. As seaweed becomes more mainstream in the U.S., it’s also showing up in new forms, like crunchy seaweed snacks and algae oil. Seaweed snacks, like [any processed food](http://time.com/5157885/processed-foods-cancer/), can be high in sodium and additives, but Hatanaka says they can be a healthier replacement for chips and crackers. Algae oil can be a good alternative to fish oil for those who don’t eat animal products (or simply don’t like the taste), says Nancy Oliveira, a senior nutritionist at Brigham and Women’s Faulkner Hospital in Massachusetts. Like fish oil, algae oil contains heart-healthy fatty acids. ## Seaweed is a low-calorie way to get nutrients Since there are so many kinds of seaweed, it’s difficult to issue a blanket statement about their nutrition, Oliveira says. But “overall, \[it’s\] fairly low in calories,” she says, and many varieties are lower in sodium than their salty tastes would suggest. “People will use dried kelp instead of the salt shaker. That can be useful if people are trying to cut down on actual table salt.” Many types of seaweed have as much protein and as many amino acids per gram [as beef](http://time.com/5505442/healthy-protein-plant-meat/), according to [a research review](https://academic.oup.com/nutritionreviews/advance-article/doi/10.1093/nutrit/nuy066/5370317) recently published in _Nutrition Reviews_ — but since seaweed servings are typically quite small, it may not be realistic to eat equivalent amounts. The digestibility of seaweed proteins also varies by type, according to the paper. Many types of seaweed are also rich in fiber. A five-gram serving of brown algae, for example, has about 14% of a person’s recommended daily fiber, according to the _Nutrition Reviews_ paper. Fiber aids healthy digestion and keeps you feeling full longer, and research also suggests that fiber-rich foods [can help prevent chronic conditions](http://time.com/5499365/fiber-lowers-risk-disease/) including heart disease and some types of cancer. In addition to fiber, [some research has shown](https://www.ncbi.nlm.nih.gov/pubmed/21779093) that a compound in seaweed, called alginate, may help control appetite and help people eat fewer calories. Many varieties also contain polysaccharides, which can improve [gut health](http://time.com/5556071/gut-health-diet/) and “help to give you a feeling of satiety,” Oliveira says. Seaweed also comes with many nutrients, Hatanaka says. “Even with a smaller amount of seaweed, you can get a lot more nutrients out of it than ground vegetables,” Hatanaka says, such as magnesium and iron. Many seaweeds also contain vitamin A, vitamin K, folate and some vitamin B12, though not all types contain B12 that can be digested by humans. ## But there are some health drawbacks [Research has found](https://www.ncbi.nlm.nih.gov/pubmed/26817952) that heavy metals lurking in contaminated water, including arsenic, aluminum, cadmium, lead, rubidium, silicon, strontium and tin, can taint some types of seaweed, though the type and amount of contamination can vary drastically depending on the plant’s natural habitat. Hijiki, a thin seaweed that looks black when cooked and is often used in Japanese and Korean appetizers, is the most commonly affected by arsenic exposure. Health officials in the U.S. and Australia, as well as some countries in Europe and Asia, have issued [public-health warnings](https://www.atsdr.cdc.gov/csem/csem.asp?csem=1&po=5) about this type of seaweed, but it’s often still possible to buy and order it. Some nutrients in seaweed, while healthy for many diners, can also pose health risks for some people. Seaweed can also absorb iodine from sea water, which may be problematic for people who have thyroid disorders, since it can throw off the thyroid’s ability to make hormones, Oliveira says. Seaweed tends to be high in vitamin K, which can interact poorly with blood thinners, and potassium, which can be dangerous for people with heart and kidney conditions that prevent them from filtering excess potassium out of the body, she says. For those reasons, Oliveira says people should eat seaweed in moderation. While periodic seaweed salads or sushi rolls are likely nothing to worry about, Oliveira recommends thinking of seaweed more as a condiment than a main dish. “My fear is that people are going to take it as a superfood…and eat a lot of it,” Oliveira says. “Eating bowls of seaweed every single day could be too much of these trace minerals.” Hatanaka agrees, noting that seaweed isn’t a daily staple of a typical Japanese diet either. “I would definitely limit consumption,” she says. In Japanese cuisine “it’s more of a side dish, where you would eat it once or twice a week — or we would sprinkle some on miso soup, but those are very minimal amounts.” ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/5559578/is-seaweed-healthy/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/5559578/is-seaweed-healthy/"},"headline":"Is Seaweed Healthy? 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