Food and Nutrition

New Study Shows That Red Seaweed Is a Superhero for Your Gut Health—Here’s How To Eat More of It

Erica Sloan

Stocksy/Harald-Walker
Seaweed (aka algae) has deep roots in nutritional stardom. For starters, it’s loaded with magnesium, folate, iodine, zinc, and a host of other health-supporting vitamins and minerals. As evidence of its powers, just consider its spot among the most commonly eaten foods of thriving Japanese centenarians. But according to recent research, not all seaweed is created equally, and one type—red seaweed, that is—packs major benefits when it comes to gut health in particular.

In a study published last week, researchers identified sugars in red seaweed that have strong prebiotic abilities, which means they serve as food for good gut bacteria, and could help those probiotics thrive in your system, says Lauren Slayton, MS, RD, the founder of nutrition-consulting company Foodtrainers. And from what we know about the gut microbiome, whenever the good bacteria flourish, the bad ones naturally diminish—and you’re less likely to experience gastrointestinal upset, from constipation to diarrhea.

"Fiber makes up 25 to 75 percent of seaweed’s dry weight, which is on the high end for vegetables. And many kinds of fiber serve a prebiotic role, as well, promoting growth of healthy bacteria in the colon." —Kim Melton, RD

Specifically, the scientists found that a sugar called agarotriose was fermented (aka consumed) by a couple different strains of the probiotic bifidobacterium, which has been linked to things like a well-functioning immune system and a balanced mood, alongside a healthy gut, of course. “We also know that fiber makes up 25 to 75 percent of seaweed’s dry weight, which is on the high end for vegetables,” says Kim Melton, RD, “and many kinds of fiber serve a prebiotic role, as well, promoting growth of healthy bacteria in the colon.”

In addition to zeroing in on its prebiotic benefits, however, the scientists in the above study also identified another sugar in red seaweed called 3,6-anhydro-L-galactose, or AHG, which they discovered had anti-cancer properties when tested with colon cancer cells in vitro (meaning, in a petri dish).

Considering all of the above gut-health benefits of red seaweed, the researchers speculated that eating a good deal of red algae may be one reason why people in Japan regularly have the lowest rates of colon cancer in the world. But of course, other factors could play into that, too—namely, other dietary contributors of fiber, more active lifestyles, and lower stress levels among people in Japan, says Melton.

Below, Slayton and Melton share easy, nutritious ways to incorporate red seaweed into your diet.

How to eat red seaweed

First things first: There are two common types of red seaweed—nori and dulse. Nori is the paper-thin seaweed used to wrap sushi (and sold in snackable strips)—and yes, despite its green color, it’s actually in the red seaweed family. “Nori is also delicious in eggs and doubles as a grain-free wrapper for sandwiches,” says Slayton.

By contrast, dulse is a reddish-purple seaweed that’s often called the “bacon of the sea.” It has a savory, salty taste and slightly chewy texture, so you can actually fry it up just like you would strips of bacon. Slayton also suggests flaked dulse, which she adds to soups and blends into dips.

Looking for more ideas? Consider these rice bowls, noodle dishes, and salads. Whenever you pair red seaweed with avocado, carrots, chickpeas, lentils, beans or any other high-fiber foods, you’re also upping the overall fiber content of your dish, says Melton, which is always a great thing when it comes to gut health.

One caveat: Before diving into the deep end with seaweed, it’s important to remember that health (and even gut health) isn’t all about any singular food. And with red seaweed, in particular, because of its iodine and potassium content, eating it multiple times a day wouldn’t be recommended, adds Slayton, especially for anyone with hypothyroidism or small intestinal bacterial overgrowth (SIBO). That said, incorporating red seaweed into a meal twice or three times a week is an ideal way to safely reap its full slate of gut health benefits.

For more food ideas to help optimize your gut health, watch this video:

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