Table of ContentsView AllTable of ContentsHealth Benefits of SeaweedOther BenefitsNutrition FactsTypes to EatWhat’s a Safe Quantity?Potential Side EffectsSourcing Reputable Seaweed
Table of ContentsView All
View All
Table of Contents
Health Benefits of Seaweed
Other Benefits
Nutrition Facts
Types to Eat
What’s a Safe Quantity?
Potential Side Effects
Sourcing Reputable Seaweed
In Asia, many people eat seaweed daily. It’s not as common in Western countries, where it’s most often found in sushi. It can also be used in various dishes, including soups, salads, stews, and smoothies. Eating seaweed may benefit your thyroid,blood sugar,heart, and more.
Seaweed has many different flavors depending on how it’s prepared. Common varieties are often described as salty, umami (earthy), fishy, or briny. The texture may be anywhere from rubbery to crispy.
This article discusses the health benefits of seaweed, possible risks and side effects, and how to eat it safely.
MiMaLeFi/ Getty Images
8 Seaweed Benefits You Might Not Expect
Much of what experts know about seaweed benefits comes from laboratory or animal studies. However, human trials are increasing, and seaweed’s long history as part of a human diet means it’s well-established as safe for regular consumption.
Evidence shows that seaweed benefits your blood pressure, weight, cholesterol, and more.
20 Healthiest, Nutrient-Dense Vegetables
Diabetes/Blood Sugar Control
Research found seaweed may help withdiabetesand blood sugar regulation. In one study of brown seaweed, participants saw a significant improvement inhemoglobin A1c (HbA1c)tests, an essential measurement of blood sugar control.
Multiple reviews also report that seaweed positively impacts blood sugar levels, especially in people withtype 2 diabetes. The effect appears to happen soon after consumption. However, the longer-term impact is unknown.
Blood Pressure Regulation
High blood pressure (hypertension) is a significant risk factor for heart disease andstroke. Research suggests seaweed may help lower blood pressure, possibly due to how your body processes sodium.
Excess sodium consumption is linked to high blood pressure.Alginate and other compounds bind to sodium and will excrete it, which prevents the body from absorbing the sodium and, in turn, will not have the effect on blood pressure that sodium normally does.
Other components in seaweed may have an effect similar to blood pressure medications calledangiotensin converting enzyme (ACE) inhibitors. Both the medications and seaweed inhibit the chemical known as angiotensin converting enzyme.
Studies show a dose of seaweed above 4 grams daily for about a month is needed to see the blood pressure benefits.
Weight Control/BMI
In some research, seaweed appears to positively affect weight and waist circumference and has a slight impact onbody mass index(BMI), which are risk factors for type 2 diabetes, heart disease, and premature death.
Consumption is needed to be fairly high, more than 4 grams (g) daily. Results also haven’t been consistent across studies; in one, the effects were seen only in males.
Cholesterol/Blood Lipids
High cholesterol levels and other blood lipids increase your risk of heart and metabolic diseases. Seaweed is a high-fiber food;high-fiber dietsare a known way to lower these levels.
Studies are mixed as to seaweed’s actual effect on human lipid levels. Some research has found that seaweed consumption may lower levels oftriglycerides(a fat in the blood) andlow-density lipoprotein (LDL) cholesterol (“bad” cholesterol)and increasehigh-density lipoprotein (HDL) cholesterol (“good” cholesterol).However, another study reported increased triglycerides after four weeks of a high-seaweed diet.
Possible seaweed benefits with less evidence backing them include:
Possible LinksAlthough more research is needed, some studies uncovered links between eating seaweed and a lower risk of:Colorectal cancerMetabolic syndromeOsteoporosisDeath
Possible Links
Although more research is needed, some studies uncovered links between eating seaweed and a lower risk of:Colorectal cancerMetabolic syndromeOsteoporosisDeath
Although more research is needed, some studies uncovered links between eating seaweed and a lower risk of:
Nutrition Facts for Single Serving of Seaweed
Nutritionally, seaweed is similar to many vegetables. It’s low in sugar and fat but packed with nutrients.
If you’re not accustomed to eating seaweed, you may want to start with small amounts of dried seaweed and increase it as you get used to the flavor or find ways you like it. Even a single tablespoon offers some nutritional benefits.
Comparing Fresh, Roasted, and Dried Seaweed
You can eat fresh seaweed right out of the ocean. Fresh seaweed is commonly used in seaweed salads.
Most commercially available seaweed is dried through roasting. This includes the variety called nori, which is the standard sushi seaweed. Nori comes in thin, dry strips often wrapped around a sushi roll.
How Much Is Too Much Seaweed?
While seaweed may offer some health benefits, eating too much of it could become a problem. This is due to its iodine and heavy metal content.
Iodine
Most people in the United States and other developed countries get enough iodine in their diets.Iodine intake over 1,100 mcg is considered dangerous. If you include seaweed in your diet, keep your total iodine consumption under that level.
Heavy Metals
Heavy metals can contaminate seaweed in the water where it grows. Washing and cooking may not remove them effectively.
Heavy metals such asmercurycan impair thyroid function. Your thyroid health may take a double hit from large amounts of seaweed.
While heavy metals in seaweed may be relatively low, regularly eating it can lead to heavy metal toxicity. One study showed healthy adults who ate large amounts of seaweed had elevated levels ofarsenic.
Side effects of excess dietary iodine include:
Symptoms ofhypothyroidism(low thyroid function), which may result from eating too much iodine, can be:
Heavy metals may cause the following side effects:
Research suggests eating seaweed once or twice a week is likely safe.Use caution when consuming more than that. Speak with a healthcare provider before consuming seaweed if you are concerned.
Many types of seaweed are available online and in stores, especially in Asian markets. These products are not required to list iodine or heavy metal content.
However, most commercial seaweed is farmed, not harvested from the sea, which should reduce the risk of heavy metal contamination.You may learn the seaweed’s source from the label or the company’s website.
When buying dried seaweed, be sure it’s in a sealed, air-tight container. It shouldn’t be especially crumbly or look gray. Properly packaged dry seaweed should last for a long time.
Summary
Seaweed can be used in sushi, soups, salads, and smoothies. Although more research is needed, some evidence shows seaweed may benefit your thyroid function, blood sugar, heart, and more. Seaweed can be eaten raw, or it can be dried or roasted.
While seaweed is packed with nutrients, too much may be a problem due to the iodine and heavy metal content. Too much iodine in your diet can impact thyroid function, leading to hypothyroidism. Speak to a healthcare provider if you’re concerned before consuming seaweed.
13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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MedlinePlus.ACE inhibitors.
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