Kelp: The Oceanic Plant With Skin, Health & Thyroid Benefits*

When you think of kelp, you probably think of slimy green seaweed, not a nutrient-dense edible seaweed. But this large brown algae that you may have seen in the ocean is a natural source of some key minerals and vitamins our bodies need and boasts potential benefits ranging from weight maintenance to bone health.*

Kelp is a kind of large brown algae. You might know kelp by its more colloquial moniker: seaweed. There are at least 30 different kinds of kelp, all of which grow in saltwater (primarily oceans) and thrive in cool, relatively shallow waters close to the shore. You won't often find just a little kelp, though. It grows in dense, forest-like groupings known, appropriately, as kelp forests.

"Kelp is often called a 'superfood from the sea' because it has 10 times more calcium than milk and more vitamin C than OJ," said Robin Berzin, M.D., functional medicine doctor and the founder of Parsley Health. "While kelp contains dozens of essential vitamins and minerals, it's difficult to find kelp on the menu and get it into one's daily diet" she told mbg. Not to worry, though, kelp can be found as a powdered supplement, and it’s easy to add to smoothies, soups, and baked goods.

Kelp is one of the best natural sources of iodine3, which is essential for thyroid hormone production.* Iodine deficiency can lead to goiter—an enlargement of the thyroid gland—and metabolism disruptions4 (which can cause things like weight changes among other symptoms).* 

"The recommended daily intake3 of iodine is 150 mcg for healthy adults, but if you're pregnant or breastfeeding, then your needs are higher (220 mcg and 290 mcg)," registered dietitian and nutritionist Jess Cording, M.S., R.D., CDN, says. "While iodine deficiency is pretty rare in the U.S., if you don't regularly consume iodized salt or are on a vegan diet, then you need to be more mindful to work iodine-rich foods into your regular diet. Seaweed is a great example of a plant-based food source.”

However, you should also be mindful that too much iodine can be a problem. The tolerable upper intake level5 for iodine is 1,100 mcg for adults, and consuming more than this can cause many of the same problems as consuming too little iodine6, including goiters, thyroid gland inflammation, and thyroid disorders.  

While kelp is a great source of all of the above vitamins and nutrients, its real claim to fame nutritionally is as a plant-based source of calcium—it's a better source than most vegetables, including kale.

Kelp contains a natural fiber called alginate, which studies have found can inhibit fat absorption in the gut by 75%.* As a result, kelp is being researched as a weight maintenance supplement that could be added to foods like yogurt.* More research is needed to confirm these findings, though. 

"Since kelp is a large brown seaweed, it may not seem like the most appetizing thing, but you can try it in several different forms," Cording said. There's raw, powdered, and dried. 

By now, it should be clear that most research supports the consumption of kelp for good health.* But overachieving kelp is also a great thing to put on your body—or at least on your skin. Brown algae has many benefits for skin12: It's high in antioxidants12 and, when applied topically, will help reduce redness and swelling. In addition, kelp is also a great moisturizer.

Finding kelp-enhanced skin care products isn't difficult. Many skin treatments and cosmetics already contain algae, both because of its specific skin benefits and because, on a purely practical production level, algae is a great industrial thickener.