Can you eat Japanese seaweed salad while pregnant?

Quick Answer

Yes, it is generally considered safe to eat Japanese seaweed salad in moderation during pregnancy. Seaweed is a good source of nutrients like iodine, iron, calcium, and folate that are important for fetal development. However, some types of seaweed like hijiki contain high levels of inorganic arsenic which may be harmful. As long as you avoid seaweeds that are known to accumulate toxins and excessive amounts, eating seaweed salad a couple times a week should be fine when pregnant.

Seaweed Nutrition Facts

Seaweed is highly nutritious and contains many vitamins, minerals, and other beneficial compounds. Here are some of the top nutrients found in seaweed:

  • Iodine – Helps regulate thyroid function which is important in pregnancy. Seaweed is one of the best food sources of iodine.
  • Folate – Essential for DNA synthesis and red blood cell production in the growing fetus. Folate intake is critical in early pregnancy.
  • Iron – Needed to make hemoglobin and prevent anemia. Requirements for iron increase during pregnancy.
  • Calcium – Vital for fetal bone development. Seaweed contains calcium that is readily absorbed.
  • Vitamin K – Supports blood clotting and bone health. Low vitamin K levels are associated with birth defects.
  • Magnesium – Plays a role in fetal growth and development. Many pregnant women don’t get enough magnesium.

Seaweed is low in calories but provides a variety of vitamins, minerals, antioxidants, fiber, and phytonutrients that can benefit both mother and baby during pregnancy.

Benefits of Eating Seaweed Salad When Pregnant

Here are some of the top benefits of eating seaweed salad in moderation during pregnancy:

Supports thyroid function

Iodine is required to produce thyroid hormones which help regulate metabolism and many other body processes. Thyroid issues are common in pregnant women as iodine needs increase. Seaweed is one of the most abundant dietary sources of iodine. Eating just a small serving a few times a week can help meet iodine needs.

Provides folate for fetal development

Folate is a B vitamin that is critical for DNA and RNA synthesis. It helps produce new red blood cells and is especially important in early pregnancy to reduce risk of neural tube defects. Seaweed contains natural folate that is readily used by the body to support fetal growth.

Boosts iron intake

Iron requirements double during pregnancy to support increased blood volume and the developing baby and placenta. Iron deficiency is common in pregnant women. Seaweed contains non-heme iron that, when paired with vitamin C, is reasonably well absorbed by the body to prevent iron deficiency.

Good plant-based calcium source

Calcium is necessary for building strong bones and teeth in the growing fetus. Seaweed contains calcium and other bone-supporting minerals like magnesium that are more easily absorbed than calcium found in dairy. Seaweed makes a great calcium source for pregnant women who can’t or don’t consume dairy.

May support fetal brain development

Some research indicates the antioxidants, minerals, and omega-3 fatty acids found in seaweed may help support fetal brain development. More studies are needed, but the nutritional profile of seaweed looks promising for brain and nervous system health.

Contains vitamin K

Vitamin K plays an important role in blood clotting and bone metabolism. Low levels of vitamin K in pregnant women have been associated with osteopenia in newborns and certain birth defects. Seaweed is a plant-based source of vitamin K that can help maintain healthy levels.

May relieve constipation

Constipation is a common complaint during pregnancy. The fiber content in seaweed adds bulk to stools and may help get things moving again. Make sure to drink plenty of fluids when increasing fiber intake.

Nutrients in Different Types of Seaweed

There are many edible varieties of seaweed that differ slightly in their nutrition profiles. Here is a comparison of key nutrients in some popular seaweeds used in Japanese salad:

Seaweed Iodine Iron Calcium Magnesium
Kombu 1000 mcg 2.7 mg 150 mg 260 mg
Wakame 150 mcg 2.2 mg 150 mg 120 mg
Nori 115 mcg 1.5 mg 15 mg 50 mg
Dulse 165 mcg 3.2 mg 220 mg 220 mg

As you can see, seaweed varieties differ in their nutritional strengths. Kombu is especially high in iodine, while dulse contains more calcium and magnesium. To get a range of nutrients, it’s best to eat a variety of seaweeds.

Potential Concerns of Eating Seaweed When Pregnant

Although seaweed offers many benefits, there are a few potential concerns to consider:

High iodine content

Too much iodine can be problematic just like too little iodine. Exceeding the tolerable upper limit (UL) for iodine intake may affect thyroid function. Kombu, a common seaweed used in Japanese salad, provides way over the UL in just one serving. To be safe, avoid eating kombu daily.

Heavy metal accumulation

Seaweed tends to absorb and concentrate minerals from ocean water – both good ones and potentially harmful ones. Some types like hijiki are known to contain inorganic arsenic which may have negative effects in pregnancy. It’s best to avoid hijiki and limit brown seaweeds like kelp.

Difficulty determining safe amounts

Since seaweed contains such concentrated nutrition, it can be hard to determine safe serving sizes and frequencies. Consuming sheets of nori as snacks is very different than eating rehydrated wakame salad at every meal. Talk to your doctor or dietitian about appropriate seaweed intake.

Risk of contamination

Seaweed can absorb bacterial or viral contaminants from seawater. Look for seaweed products tested for purity standards to reduce the risk of exposure to harmful pathogens like Listeria.

Iodine-restrictive diets

Women with pre-existing thyroid issues may need to restrict iodine for a healthy pregnancy. In this case, seaweed intake should be limited and determined in discussion with your endocrinologist. Don’t eat seaweed daily if you’re following an iodine-restricted diet.

To minimize potential risks, eat seaweed in moderation as part of a healthy, balanced diet. Avoid types known to accumulate toxins, and choose seaweed from reputable sources.

How Much Seaweed Can You Eat Safely?

There are no official guidelines for how much seaweed pregnant women can eat daily or weekly. A common recommendation is 4-6 grams of dried seaweed or 12-18 grams fresh/rehydrated per day.

To stay on the safe side, limit your total weekly seaweed intake to 60-85 grams (about 2-3 ounces). This allows you to get important nutrients while avoiding excessive amounts of iodine, heavy metals, and other contaminants.

When eating seaweed salad, a serving size of around 1/2 cup prepared salad (40 grams) two or three times per week is generally safe if using a mix of different seaweed varieties. Pay attention to signs of excessive iodine like throat irritation or hyperthyroid symptoms.

Best Seaweeds to Eat When Pregnant

These are some of the top seaweeds to include in your diet regularly while pregnant:

  • Nori – Popular in sushi rolls, nori is low in minerals but provides protein, omega-3s, and antioxidants.
  • Wakame – Contains fucoxanthin which supports metabolism and blood sugar control.
  • Dulse – High in iron, calcium, and other minerals; relatively low in iodine.
  • Sea lettuce – Low in iodine and a good source of soluble fiber, vitamins, and minerals like iron, calcium, and magnesium.

Focus on eating a variety of the safer seaweeds in moderation. Avoid daily portions of very mineral-dense seaweeds like kombu and kelp which can provide excessive iodine.

Seaweeds to Avoid or Limit When Pregnant

These types of seaweed have more potential to cause harm and are best minimized or avoided altogether during pregnancy:

  • Hijiki – Contains inorganic arsenic compounds that may be toxic to the developing fetus.
  • Kombu/kelp – Very high in iodine. Excessive intake can affect thyroid function.
  • Sargassum – Can contain thyroid-disrupting compounds if harvested from polluted waters.
  • Bladderwrack – Has variable iodine content that may be hard to control.

If choosing to eat these seaweeds occasionally, stick to small portions of a tablespoon or less once or twice a month. But it’s safest to avoid them altogether, especially hijiki and kombu.

Healthy Ways to Eat Seaweed Salad When Pregnant

Here are some healthy ways to enjoy seaweed salad during pregnancy:

  • Make seaweed salad at home from scratch using a combination of safer seaweeds like wakame, dulse, and nori.
  • Add rehydrated seaweed salad to rice bowls, noodle dishes, and stir fries.
  • Snack on toasted seaweed sheets in between meals for a savory, crunchy treat.
  • Use seaweed flakes as a mineral-rich seasoning for soups, salads, and other foods.
  • Wrap sushi with nori instead of rice now and then – it provides fewer calories and more nutrients.
  • Choose pre-made seaweed salad at restaurants and limit to 1/2 cup portions a few times weekly.
  • Look for organic, sustainably harvested seaweed products when possible.

Pair seaweed with vitamin C-rich foods like citrus, peppers, or broccoli to enhance iron absorption. Stay hydrated and get plenty of fiber to counteract the constipating effects.

Seaweed Salad Recipe for Pregnancy

This pregnancy-friendly seaweed salad combines wakame, dulse, and nori – a tasty blend that provides nutrition while avoiding excessive iodine and heavy metals:


  • 1 cup dried wakame seaweed, cut into strips
  • 1/4 cup dried dulse seaweed, cut into strips
  • 1 sheet nori seaweed, sliced into thin strips
  • 1 medium cucumber, thinly sliced
  • 1 carrot, peeled and grated
  • 3 tbsp rice vinegar
  • 1 tbsp toasted sesame oil
  • 1 tbsp toasted sesame seeds


  1. Rehydrate wakame and dulse seaweed by soaking in separate bowls of water for 5 minutes. Drain and gently squeeze out excess moisture.
  2. In a large bowl, combine rehydrated wakame and dulse seaweed, sliced nori, cucumber, and grated carrot.
  3. In a small bowl, whisk together rice vinegar, sesame oil, and sesame seeds. Pour dressing over seaweed and veggies and toss gently to coat evenly.
  4. Chill seaweed salad for 30 minutes before serving for best flavor and texture.

This salad provides a nutritious mix of sea vegetables along with some veggie power from the cucumber and carrot. Enjoy this pregnancy-safe seaweed salad as a side dish a few times per week for optimal nutrition.

The Bottom Line

Seaweed offers many nutritional benefits for pregnant women and unborn babies when eaten regularly in moderation as part of an overall healthy diet. Focus on eating a variety of seaweeds and amounts that are unlikely to cause excessive iodine or toxin exposure. To stay on the safe side, limit total weekly seaweed intake and avoid kinds like hijiki that may contain dangerous compounds. Seaweed salad can be included safely in pregnancy when certain precautions are followed.

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