The Benefits of Kelp Will Convince You to Snack On This Sea Veggie

Step aside sushi, this seaweed goes way beyond your basic roll. Read up on all the benefits of kelp and its many forms.

Kelp, a type of seaweed, can be intimidating to cook at home if you haven't done so before — but if you're a fan of Chinese, Japanese, or Korean cuisine, you've likely already eaten your fair share. The nutrient-dense seaweed is a go-to ingredient for countless dishes, from chilled salads to savory soups.

But kelp is far from your average sea vegetable. With its impressive roster of nutrients and antioxidants, it may very well be a superfood of the sea. Here, explore the health benefits of kelp, its nutrition content, and ways to use it in your kitchen.

What Is Kelp?

Kelp is a large, leafy brown seaweed or algae that grows in cool water along rocky coastlines. It's very fast-growing, tacking on about 1.5 feet per day, according to the National Park Service, with some species that can reach lengths of 150 feet. Basically, if the world of seaweed had a head honcho, kelp would be it.

Due to its size, kelp looks like an underwater tree. But unlike true plants, this aquatic algae doesn't actually have roots. Instead, kelp secures itself to the rocky ocean floor, then grows from there, forming dense clusters called kelp forests. Some species thrive in the northern Pacific Ocean — from Baja, California to Japan — while others call the northwest Atlantic home. They also grow along the coasts of South Africa, New Zealand, and Australia. Regardless of the location, kelp forests are amazingly complex, offering food and shelter to thousands of animals. Other types of seaweed don't grow in packed groups, let alone produce actual ecosystems. The sheer size of kelp is also noteworthy; it's a giant compared to other seaweeds.

What makes kelp similar to its underwater cousins, however, is that it's super sustainable. Kelp and other seaweeds can be farmed with minimal impact on the environment, according to research published in the Marine Pollution Bulletin. (They're typically taken out of the water using anchored ropes called long-lines.) What's more, aquatic veggies are plentiful, fast-growing, and do not need to be fertilized, watered, or weeded, all of which are typically required when cultivating produce on land and can negatively impact the environment.

Kelp Nutrition Facts

"Kelp is highly nutritious because it's high in minerals, vitamins, and antioxidants," says Liz Wyosnick, M.S., R.D.N., a registered dietitian nutritionist and owner of Equilibriyum. It also "has iron, zinc, calcium, copper, and vanadium, [a mineral] linked to blood sugar regulation," she adds.

"Kelp is a great source of iodine, vitamin C, manganese, riboflavin (vitamin B2), and various antioxidants," which help the body combat oxidative stress, notes Wyosnick. "Altogether, this unique array of compounds can help fortify the blood by supplying vital nutrients that we rarely get from typical foods," explains Wyosnick.

Here's the nutritional information for 100 grams of raw kelp, according to the United States Department of Agriculture (USDA):

  • 43 calories
  • 1.7 grams protein
  • < 1 gram fat
  • 9.5 grams carbohydrate
  • ~ 1 gram fiber
  • 168 milligrams calcium
  • 121 milligrams magnesium
  • 180 micrograms folate

Health Benefits of Kelp

Although kelp is considered a ~superfood~ (just like sea moss), it's important to know that not all kelp is equal. Kelp soaks up nutrients from the sea, so it can also pick up substances such as heavy metals and contaminants. And since "our oceans [are becoming] more polluted and unsustainable, the integrity and nutrition of the kelp may dwindle," explains Wyosnick. To get the most out of your kelp, consider buying organic seaweed farmed in clean waters, usually marked with the USDA Organic Label, recommends Wyosnick. You can also keep an eye out for sustainable certification logos, such as the "Friend of the Sea" label or ASC-MSC Seaweed Standard symbol, both of which ensure that seaweed products were ethically harvested and produced without harming the nearby natural environment.

Now that you know how to scour your market's seaweed-stocked shelves, it's time to dive into kelp's benefits on your brain and body.

Supports Bone Health

When you think of healthy bones, seaweed probably doesn't come to mind (hopefully lifting weights does!) — but the underwater veggie can totally lend a hand. "Kelp is an excellent source of calcium, as well as vitamins K, A, and B12, as well as iron," says Maya Feller, M.S., R.D., C.D.N., a registered dietitian in Brooklyn, New York. "Vitamin K is [particularly] important for bone metabolism and works with calcium and vitamin D to help maintain bone health," she adds. In order to score this nutrient's bone-building and strengthening benefits, non-pregnant folks ages 19+ should aim for 90 micrograms per day, according to the National Institutes of Health (NIH).

Regulates Thyroid Function

When it comes to kelp's benefits, this one stands out in particular. Why? Because kelp is loaded with iodine, a "key nutrient for activating thyroid hormones," says Wyosnick. Iodine helps the thyroid run properly and make thyroid hormones — which are in charge of a variety of essential functions including metabolism as well as bone and brain development during pregnancy and infancy, among other important functions, according to the NIH. So, it's a good idea to keep 'em in check.

One way to do this is to chow down on sea kelp, one of the best natural sources of iodine. In fact, some types of kelp can have up to 2,984 micrograms of iodine per sheet (1 gram), according to the NIH, which recommends 150 micrograms of iodine per day for non-pregnant people ages 19 ad older. Meaning: Just one sheet of this seaweed can provide nearly 2,000 percent of the recommended daily intake. Woah.

You'll want to use caution if you have an overactive thyroid (hyperthyroidism), though. Too much iodine (from kelp or otherwise) can worsen the condition, says Wyosnick. If you have a history of thyroid issues, chat with your doctor before digging into kelp.

Manages Blood Sugar

"Kelp is a rich source of the trace mineral vanadium, [which] may have potent hypoglycemic effects," says Feller. This means it naturally lowers your blood sugar, helping maintain healthy blood glucose levels over time. And although scientists are still learning how vanadium works, research published in Bioscience Horizons has found that vanadium can suppress enzymes involved in glucose production and the development of type 2 diabetes. A 2014 study reported similar results, stating that extracts from brown seaweeds, such as kelp, can inhibit enzymes that increase blood glucose levels. What's more, there are animal studies that have found "kelp may improve beta-cell function in the pancreas, resulting in a reduction of fasting blood glucose," cites Feller. (BTW: Beta-cells are the only cells that can make insulin, a hormone that controls blood sugar by helping cells take up glucose, according to Current Diabetes Reports.)

TL;DR — sea kelp has the power to lower blood sugar, which can, in turn, help stave off health issues, such as heart disease and diabetes.

Reduces Risk of Cancer

As mentioned above, kelp is chock-full of antioxidants. This includes nutrients such as vitamin C, along with polyphenols such as carotenoids, flavonoids, and alkaloids, according to Wyosnick. In turn, kelp is one of the best foods you can add to your cancer-prevention menu. (Olive oil is also super rich in polyphenols, BTW.)

It's thought that cancer may be more likely to occur within a highly oxidized and inflamed state, says Wyosnick. This occurs when free radicals — or molecules that damage healthy cells — build up. The antioxidants in kelp neutralize these free radicals, protecting your body against cellular damage. Oh, and when it comes to antioxidant-rich foods? "Kelp is a star because [of its] unique makeup and concentration [of polyphenols]," says Wyosnick. "Essentially, you get a lot of antioxidant bang for your buck," she adds.

Might Support Weight Loss

Although the evidence is conflicting, alginate — a compound found in seaweed — may have the potential for weight management or weight loss. A 2012 study found that, when combined with an energy- or calorie-restricted diet, alginate supplementation was associated with greater weight loss in people with obesity. The researchers attributed this effect to alginate's fiber content, which can keep hunger at bay by increasing satiety. On the flip side, another 2012 study in the journal Obesity found no effect on appetite and satiety in overweight and obese participants.

With that said, kelp is low in calories: One strip of dried kelp has just under 2 calories, for example. When eaten in lieu of other high-energy foods (such as if used as a sandwich filling instead of bacon), it could help curtail your overall calorie intake.

How to Buy and Eat Kelp

If you're wondering how to eat kelp, you're in luck: It's a surprisingly versatile food. At the grocery store, kelp can take many forms. Fresh kelp consists of long, thick strands with a greenish color. The flavor is generally briny and salty, just like (surprise!) the ocean. You can expect a similar umami taste from other forms of kelp, including dried kelp sheets and flakes. The exception is kelp noodles, which are usually quite bland. Just know that dried kelp needs to be rehydrated by soaking in water, while fresh kelp needs to be rinsed with water to remove excess salt, then drained.

It's worth noting that fresh sea kelp has a slimy, gel-like texture that may be off-putting for some folks. If you're in this boat, you may want to try kelp noodles, sheets, or flakes instead. As for nutritional differences? "The various forms of packaged kelp are comparable nutritionally, so choose the form that you are most likely to consume and use with your cooking," suggests Wyosnick. "Opt for the least processed (least number of ingredients) and watch out for added sugar or an excessive amount of added salt," she adds.

And then there are kelp supplements, which are available as pills or powders. However, when it comes to optimal absorption, they may not be the best choice, notes Wyosnick. Kelp powders and pills are often stripped of certain nutrients, while the real thing contains the full package of potential health perks. This allows for peak absorption and bioavailability by your body. But if you do want to give kelp supplements a shot, "look for supplements that have third-party certifications and are free from synthetic additives," says Feller.

Once you've stocked up, here's how you can add kelp to your weekly meal rotation.

In a stir-fry. Kelp has a tasty umami flavor, making it an awesome stir-fry ingredient. It pairs well with vegetables such as broccoli and onions, but don't be afraid to experiment — especially if you need to use up leftover produce.

With beans. Take a tip from Feller and use kelp to elevate your beans. "Beans without kelp taste earthy, [but] with kelp there is a hint of brine," she says. Simply add 1 1/2 cup dry beans to a pot, then cover completely with water. Add a few dried sheets of kombu (a type of kelp), one raw garlic clove, and half a raw onion, then leave on the countertop overnight. In the morning, add a bit of fresh water, then boil, and serve as usual. Eat the dried-kelp-and-beans creation as a side or use it to bulk up a homemade soup.

In soup. On that note, kelp is ideal for adding depth and flavor to your favorite soups. Use kelp powder as a seasoning or fresh kelp as a main ingredient in a Korean-style seaweed soup.

As pasta. For a quick way to boost your seaweed intake, try kelp noodles. These semi-translucent sea veggie spaghetti noodles have a neutral flavor, so they play well with most types of sauces or dressings. Plus, they require zero cooking time; simply soak them in water and serve.

As a seasoning. Kelp powder or flakes offer unique alternatives to your typical seasoning. Many folks sprinkle kelp on their dishes in place of added salt, as it offers a salty taste without the excess sodium. Feller loves kelp flakes on rice with sesame seeds, while Wyosnick is all about sprinkling it on avocado toast, eggs, and popcorn. Feeling adventurous? Add a dash of kelp flakes to your pizza.

In salad. Liven up your usual bowl of greens with fresh or dried kelp. The latter doubles as a healthy alternative to traditional croutons due to its satisfying crunch. Another option is to make a cold seaweed salad tossed with low-sodium soy sauce, rice vinegar, and sesame seeds.

With seafood. "Kelp goes so well with anything from the sea," says Wyosnick. "Think salmon, tuna, shrimp…or sushi, of course," she adds. Or, add it to fish tacos as a topping or mix it with tuna salad for a unique twist. Boring tuna, no more!

In green smoothies. Switch up your usual green smoothie by adding kelp powder or kelp cubes. Not into smoothies? No problem — make kelp juice by blending kelp powder with coconut water or vegetable juice.

Was this page helpful?
Related Articles