What if someone told you they knew of a nutrient-rich superfood that could complement dozens of dishes? The benefits of this mystery food would include a healthy dose of fiber, iodine and other nutrients to meals as varied as smoothies and pasta. And, they might go on, this mystery ingredient tastes pretty great as well.

If you’re scratching your head, let us introduce you to seaweed. Or, more likely, reintroduce you. We all know of seaweed as the green part of our sushi rolls, or as an ingredient in traditional Japanese miso soup. But, as foodies and health enthusiasts around the world are quickly discovering, seaweed is a versatile ingredient, as appropriate in salads or salsas as it is in sushi. And dried seaweed, lightly salted and delicately crispy, makes a great snack in its own right.

Seaweed, whether wakame, kombu, nori or another species, contains a staggering amount of nutrients per dry ounce, and the health benefits of seaweed have been backed by studies for years. The green and brown sea vegetables contain vitamin A, calcium, magnesium, potassium and iodine, as well as antioxidants like fucoxanthin, which studies show helps burn fat.

Unlike many of the commercially farmed vegetables or processed food products we eat, seaweed is a naturally sustainable crop. Growing in cold ocean waters, these plant-like organisms — technically a type of algae — help suck carbon dioxide from the water. They provide oxygen for fish and other marine life and for life on land (including us) as well (Duarte et al., 2017). Seaweed can be used as a biofuel, or fed to cows to keep their methane-filled burps in check — both wins for the environment.

One reason seaweed is so beneficial for human health may be that we co-evolved with it. The “kelp highway” hypothesis holds that human beings slowly spread out from what’s now South Africa roughly 160,000 years ago by following coastlines. If so, they would have eaten foods found on the seashore along the way: shellfish, bird eggs and kelp strewn across the beaches.

Seaweed From the Open Sea

Most seaweed we eat is harvested from the open ocean. In the U.S., sustainable seaweed operations can be found from Alaska to Maine, where fishermen and seaweed farmers haul in long strands of green and brown kelp, wakame and more from cold, clean waters. Maine-based Atlantic Sea Farms, which provides Vital Choice with natural, unadulterated kelp, is pursuing the express goal of promoting seaweed as a sustainable alternative to land-based crops while employing fishermen in their off-season.

Some species of seaweed can grow more than three feet a day, reaching over 200 feet in length. Those strands are cut up and dried to make products like kelp cubes, which can be added easily to smoothies, pesto and more for a quick boost of nutrition.

Iodine, Fiber and More

One of the most outstanding nutritional benefits of seaweed is its iodine content (Yeh et al., 2014). Some species can contain a full daily requirement of iodine in just a single serving. Iodine, along with tyrosine, another seaweed nutrient, is crucial for the thyroid gland, which produces hormones our bodies use to maintain efficient metabolism. The nutrient is critical during pregnancies as well, helping to ensure normal brain function in developing children.

Seaweed’s rich iodine content is one reason Korean women traditionally drink a soup made from wakame seaweed after giving birth. The broth, called miyeok-guk, is also often eaten on birthdays, to remember and honor a mother’s love.

Seaweed’s Secret Antioxidant

Brown seaweeds like wakame are also unusually good sources of the antioxidant fucoxanthin. Antioxidants help tamp down the activity of damaging molecules in our bodies known as free radicals, which can react with and harm our cells. The nutrient neutralizes free radicals at more than 13 times the rate of vitamin E, another common antioxidant, scientists found (Mikami and Hosokawa, 2013).

(Read more: Antioxidant Foods Appear to Keep the Doc Away)

Evidence also suggests fucoxanthin helps with weight loss. Mice fed seaweed lost abdominal fat and body weight, researchers reported in 2005 (Maeda et al., 2005). Additionally, fucoxanthin helped control blood glucose levels in mice in another study, a sign the compound could play a role in reducing symptoms of diabetes (Woo et al., 2010).

Another little-known health benefit of incorporating seaweed in your diet is its fiber content. The algae can be as much as 25 to 75 percent fiber by dry weight, more than most fruits and vegetables. There are two key reasons fiber is good for us. First, it can’t be digested by our gut, meaning fiber helps us feel full without contributing any calories to our diets. While studies don’t always show an effect on weight loss, upping your fiber intake is nevertheless an easy way to help avoid food cravings after a meal (Howarth et al., 2009).

Japanese wakame seaweed salad with chopsticks
Bright green wakame salad, a Japanese favorite, is becoming better known and more available in the U.S.

More importantly, fiber, while not a source of calories for us, is an important food for the bacteria living in the gut, collectively called the gut microbiome. In the last decade, studies have begun uncovering just how important the gut is to our overall health. The microbiome affects health conditions as varied as inflammatory bowel disease, skin disorders and mental illness (Cho and Blaser, 2012).

Studies show that people who eat unprocessed plants have healthier gut microbiomes, something researchers trace back in part to the fibers plants provide (Tuohy et al., 2012). The fiber in seaweed, along with other gut-friendly prebiotics, has been shown in animal studies to increase healthy bacteria in the gut (O’Sullivan et al., 2010). Preliminary studies in humans show similar results, though researchers note larger and more rigorous studies are needed (Cherry et al., 2019).

Though cooking with seaweed may be new to you, there are many simple, delicious ways to do it. You can use larger pieces of seaweed in soups and salads, but many people opt for an even easier route. Just chop or shred some seaweed into smaller flakes and add a half cup to everything from your morning smoothie to a hearty tomato sauce. Or, think of your seaweed more like a seasoning and sprinkle it on anything that needs a little savory “umami” flavor or salty kick.

Whatever you choose, you’ll be adding a hefty dose of vitamins, minerals and healthy fiber to your meal. With seaweed, you might just be able to make any food a superfood.

 

Sources:

  • Cherry P, Yadav S, Strain CR, et al. Prebiotics from Seaweeds: An Ocean of Opportunity? Marine Drugs. 2019;17(6):327. doi:10.3390/md17060327
  • Cho I, Blaser MJ. The human microbiome: at the interface of health and disease. Nature Reviews Genetics. 2012;13(4):260-270. doi:10.1038/nrg3182
  • Duarte CM, Wu J, Xiao X, Bruhn A, Krause-Jensen D. Can Seaweed Farming Play a Role in Climate Change Mitigation and Adaptation? Frontiers in Marine Science. 2017;4. doi:10.3389/fmars.2017.00100
  • Howarth NC, Saltzman E, Roberts SB. Dietary Fiber and Weight Regulation. Nutrition Reviews. 2009;59(5):129-139. doi:10.1111/j.1753-4887.2001.tb07001.x
  • Maeda H, Hosokawa M, Sashima T, Funayama K, Miyashita K. Fucoxanthin from edible seaweed, Undaria pinnatifida, shows antiobesity effect through UCP1 expression in white adipose tissues. Biochemical and Biophysical Research Communications. 2005;332(2):392-397. doi:10.1016/j.bbrc.2005.05.002
  • Mikami K, Hosokawa M. Biosynthetic Pathway and Health Benefits of Fucoxanthin, an Algae-Specific Xanthophyll in Brown Seaweeds. International Journal of Molecular Sciences. 2013;14(7):13763-13781. doi:10.3390/ijms140713763
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  • Tuohy KM, Conterno L, Gasperotti M, Viola R. Up-regulating the Human Intestinal Microbiome Using Whole Plant Foods, Polyphenols, and/or Fiber. Journal of Agricultural and Food Chemistry. 2012;60(36):8776-8782. doi:10.1021/jf2053959
  • Woo M-N, Jeon S-M, Kim H-J, et al. Fucoxanthin supplementation improves plasma and hepatic lipid metabolism and blood glucose concentration in high-fat fed C57BL/6N mice. Chemico-Biological Interactions. 2010;186(3):316-322. doi:10.1016/j.cbi.2010.05.006
  • Yeh TS, Hung NH, Lin TC. Analysis of iodine content in seaweed by GC-ECD and estimation of iodine intake. Journal of Food and Drug Analysis. 2014;22(2):189-196. doi:10.1016/j.jfda.2014.01.014