Seaweed can contain beneficial nutrients, including iodine, and antioxidants. It may support heart health. What’s more, seaweed is highly nutritious, so a little goes a long way.
Here are 7 science-backed benefits of seaweed.
- Contains Iodine and Tyrosine, Which Support Thyroid Function
Your thyroid gland releases hormones to help control growth, energy production, reproduction and the repair of damaged cells in your body.
Your thyroid relies on iodine to make hormones. Without enough iodine, you may start to experience symptoms like weight changes, fatigue, or swelling of the neck over time.
The recommended dietary intake (RDI) of iodine for adults is 140 mcg per day.
Seaweed has the unique ability to absorb concentrated amounts of iodine from the ocean.
Its iodine content varies greatly depending on the type, where it was grown, and how it was processed. In fact, one dried sheet of seaweed can contain 11–1,989% of the RDI.
Below is the average iodine content of three different dried seaweeds (8):
Nori: 37 mcg per gram (25% of the RDI)
Wakame: 139 mcg per gram (93% of the RDI)
Kombu: 2523 mcg per gram (1,682% of the RDI)
Kelp is one of the best sources of iodine. Just one teaspoon (3.5 grams) of dried kelp could contain 59 times the RDI.
Seaweed also contains an amino acid called tyrosine, which is used alongside iodine to make two key hormones that help the thyroid gland do its job properly.
- Good Source of Vitamins and Minerals
Each type of seaweed has a unique set of nutrients.
Sprinkling some dried seaweed on your food not only adds taste, texture, and flavor to your meal, but it’s an easy way to boost your intake of vitamins and minerals.
Generally, 1 tablespoon (7 grams) of dried spirulina can provide:
Calories: 20
Carbs: 1.7 grams
Protein: 4 grams
Fat: 0.5 gram
Fiber: 0.3 grams
Riboflavin: 20% daily value (DV)
Thiamin: 14% DV
Iron: 11% DV
Manganese: 6% DV
Copper: 47% DV
Seaweed also contains small amounts of vitamins A, C, E, and K, along with folate, zinc, sodium, calcium, and magnesium.
While it may only contribute to a small percentage of some of the DVs above, using it as a seasoning once or twice per week can be an easy way to add more nutrients to your diet.
The proteins present in some seaweeds, such as spirulina and chlorella, contain all of the essential amino acids. This means seaweed can help ensure you get the full range of amino acids.
Seaweed can also be a good source of omega-3 fats and vitamin B12.
It appears that dried green and purple seaweed contain substantial amounts of vitamin B12. One study found 2.4 mcg or 100% of the RDI of vitamin B12 in only 4 grams of nori seaweed.
That said, there is an ongoing debate about whether your body can absorb and use the vitamin B12 from seaweed.
- Contains a Variety of Protective Antioxidants
Antioxidants can make unstable substances in your body called free radicals less reactive. This makes them less likely to damage your cells. Furthermore, excess free radical production is considered to be an underlying cause of several diseases, such as heart disease and diabetes.
In addition to containing the antioxidant vitamins A, C, and E, seaweed boasts a wide variety of beneficial plant compounds, including flavonoids and carotenoids. These have been shown to protect your body’s cells from free radical damage.
A lot of research has focused on one particular carotenoid called fucoxanthin. It’s the main carotenoid found in brown algae, such as wakame, and it has 13.5 times the antioxidant capacity of vitamin E. Fucoxanthin has been shown to protect cell membranes better than vitamin A. While the body does not always absorb fucoxanthin well, absorption may be improved by consuming it along with fat.
Nevertheless, seaweed contains a wide variety of plant compounds that work together to have strong antioxidant effects.
4. Provides Fiber and Polysaccharides That Can Support Your Gut Health.
Gut bacteria play an enormous role in your health. It’s estimated that you have more bacteria cells in your body than human cells. An imbalance in these “good” and “bad” gut bacteria can lead to sickness and disease.
Seaweed is an excellent source of fiber, which is known to promote gut health. It can make up about 25–75% of seaweed’s dry weight. This is higher than the fiber content of most fruits and vegetables. Fiber can resist digestion and be used as a food source for bacteria in your large intestine instead.
Additionally, particular sugars found in seaweed called sulfated polysaccharides have been shown to increase the growth of “good” gut bacteria. These polysaccharides can also increase the production of short-chain fatty acids (SCFA), which provide support and nourishment to the cells lining your gut.
- May Help You Lose Weight by Delaying Hunger and Reducing Weight
Seaweed contains a lot of fiber, which does not contain any calories. The fiber in seaweed may slow stomach emptying, too. This helps you feel fuller for longer and can delay hunger pangs.
Seaweed is also considered to have anti-obesity effects. In particular, several animal studies suggest that a substance in seaweed called fucoxanthin may help reduce body fat.
- May Reduce Heart Disease Risk
Heart disease is the leading cause of death worldwide. Factors that increase your risk include high cholesterol, high blood pressure, smoking, and being physically inactive or overweight. Seaweed may help reduce your blood cholesterol levels.
- May Help Reduce Your Risk of Type 2 Diabetes by Improving Blood Sugar Management
Diabetes occurs when your body is unable to balance your blood sugar levels over time. By the year 2040, 642 million people worldwide are expected to have type 1 or type 2 diabetes. Interestingly, seaweed has become a research focus for new ways to support people who are at risk of diabetes. An 8-week study of 60 Japanese people revealed that fucoxanthin, a substance in brown seaweed, may help improve blood sugar control. What’s more, another substance in seaweed called alginate prevented blood sugar spikes in animals after they were fed a high-sugar meal. It’s thought that alginate may reduce the absorption of sugar into the bloodstream.
Medically reviewed by Amy Richter, RD, Nutrition — By Sharon O’Brien MS, PGDip — Updated on March 13, 2023 (healthline.com)
