By the Nutriveda editorial team · Updated 5 November 2026
Wakame (Undaria pinnatifida) is a brown seaweed with soft, silky green leaves, best known as the seaweed in Japanese miso soup and in seaweed salads. 100 g of raw wakame has only 45 kcal and gives 196 µg of folate, 107 mg of magnesium and 150 mg of calcium. Like other seaweeds it can carry a lot of iodine, but how much varies so widely from pack to pack that no honest single number exists. A portion is small, a couple of tablespoons, so wakame is a flavour and a bonus, not a main source of anything except iodine and salt.
Wakame nutrition per 100 g and per portion
| Nutrient | Raw, 100 g | 2 tbsp (10 g) | Small salad side (50 g) |
|---|---|---|---|
| Energy | 45 kcal | 5 kcal | 23 kcal |
| Protein | 3.0 g | 0.3 g | 1.5 g |
| Fat | 0.6 g | 0.1 g | 0.3 g |
| Carbohydrate | 9.1 g | 0.9 g | 4.6 g |
| of which sugars | 0.65 g | 0.1 g | 0.3 g |
| Fibre | 0.5 g | 0.1 g | 0.3 g |
| Folate | 196 µg | 20 µg | 98 µg |
| Magnesium | 107 mg | 11 mg | 54 mg |
| Calcium | 150 mg | 15 mg | 75 mg |
| Iron | 2.2 mg | 0.2 mg | 1.1 mg |
| Manganese | 1.4 mg | 0.14 mg | 0.7 mg |
| Sodium | 872 mg | 87 mg | 436 mg |
| Iodine | no data | no data | no data |
Source: USDA FoodData Central, SR Legacy: “Seaweed, wakame, raw” (FDC 170496), checked 5 November 2026. The record’s measure is 2 tbsp (1/8 cup) = 10 g; the 50 g column is calculated. The record also lists 0.19 g of EPA, a long-chain omega-3, per 100 g. It gives no iodine value. Values rounded.
Most wakame in European shops is sold dried. Dried wakame swells a lot in water and is much more concentrated by weight than the raw values above, so check the pack. Ready-made “seaweed salad” from the chiller is a different product again, usually with added sugar, sesame oil and salt.
Glycemic index
Wakame is not listed in the international GI tables (Atkinson 2008). A usual portion of 10 g adds less than 1 g of carbohydrate to a meal, so the glycemic index does not matter in practice. More in What is the glycemic index? (with food table).
Health benefits: what the evidence says
- Iodine. The NIH Office of Dietary Supplements names seaweed, including kelp, nori, kombu and wakame, as one of the best food sources of iodine, which the thyroid needs to make its hormones. The adult RDA is 150 µg a day (220 µg in pregnancy, 290 µg when breastfeeding). NIH also notes that commercial seaweeds range from 16 to 2,984 µg of iodine per gram, so a single serving can give far too little or far too much. That is why we do not give an iodine number for wakame.
- Folate. 100 g of raw wakame has 196 µg of folate, more than most vegetables. In a realistic 10 g portion that is 20 µg, so wakame adds to your folate rather than covering it.
- Magnesium and calcium. Per 100 g, wakame has 107 mg of magnesium and 150 mg of calcium. A small salad of 50 g gives about 54 mg and 75 mg.
- A little EPA. USDA lists 0.19 g of EPA per 100 g of wakame. NIH explains that EPA and DHA are originally made by microalgae at the base of the marine food chain, not by fish. In a 10 g portion the amount is about 19 mg, small next to oily fish such as sardines, so wakame is a curiosity here, not a fish substitute.
- Very few calories. 45 kcal per 100 g and almost no fat. Wakame adds texture and a mild sea flavour for almost no energy.
How to eat wakame
- Rehydrate: soak dried wakame in cold water for about 5-10 minutes until soft and green, drain and squeeze out the water. Start with a small pinch; it grows.
- Miso soup: add rehydrated wakame and cubes of tofu to hot dashi, take it off the boil and stir in miso. Do not boil after the miso goes in.
- Salad: toss wakame with cucumber, rice vinegar, a few drops of sesame oil and toasted sesame seeds. Add ginger if you like it sharper.
- With rice and fish: a spoon of wakame on a rice bowl with salmon or egg.
- Salt: both wakame and miso bring salt, so do not add more to the soup.
- Storage: keep dried wakame closed in a dry, dark place. Once soaked, use it the same day or keep it in the fridge for a day or two.
Who should be careful
- Thyroid conditions. NIH explains that too much iodine can cause some of the same problems as too little: goiter, raised TSH and hypothyroidism, and also iodine-induced hyperthyroidism and thyroiditis. People with autoimmune thyroid disease are especially sensitive. If you have a thyroid condition, ask your doctor before eating seaweed often.
- Thyroid medication. NIH notes that high doses of iodine taken with antithyroid medicines can have an additive effect. Do not change your seaweed intake a lot without telling your doctor.
- Upper limit. NIH sets the tolerable upper intake level for iodine at 1,100 µg a day for adults, 200 µg for children aged 1-3 and 300 µg for ages 4-8. With seaweed ranging up to almost 3,000 µg per gram, daily large amounts, seaweed snacks for children and seaweed supplements are where the risk lies. Small portions a few times a week are a different story.
- Salt. 100 g of raw wakame has 872 mg of sodium, about 2.2 g of salt. If you are on a low-salt diet, keep portions small.
Traditional view (Ayurveda)
Usha and Vasant Lad’s food guidelines do not list wakame by name. Seaweed in general is favourable for Vata and favourable in moderation for Pitta and Kapha. This is a traditional system, not clinical evidence.
Related entries and articles
- Seaweed – the main types and how they differ
- Kelp – another brown seaweed, often sold as a supplement
- Nori – the dried sheets for sushi
- Miso – the other half of miso soup
- Tofu
- Spirulina – a different kind of algae, sold as a powder
FAQ
Is wakame high in iodine?
It can be. NIH lists wakame among the seaweeds that are some of the best food sources of iodine, but commercial seaweeds range from 16 to 2,984 µg per gram. Small portions a few times a week suit most people; daily large amounts may go over the adult upper limit of 1,100 µg.
Can I eat wakame every day?
A small pinch in miso soup is how many people eat it, but because the iodine in seaweed is so unpredictable, daily large portions are not a good idea. If you have a thyroid condition or take thyroid medicine, ask your doctor first.
Is wakame good for the thyroid?
The thyroid needs iodine, and seaweed is one of the richest sources. More is not better, though: NIH explains that too much iodine can cause goiter, hypothyroidism or hyperthyroidism, especially in people with autoimmune thyroid disease.
Sources
- USDA FoodData Central, SR Legacy: Seaweed, wakame, raw (FDC 170496). fdc.nal.usda.gov
- NIH Office of Dietary Supplements: Iodine, Fact Sheet for Health Professionals (updated 5 November 2024). ods.od.nih.gov
- NIH Office of Dietary Supplements: Omega-3 Fatty Acids, Fact Sheet for Health Professionals. ods.od.nih.gov
- Atkinson FS, Foster-Powell K, Brand-Miller JC. International Tables of Glycemic Index and Glycemic Load Values: 2008. Diabetes Care 2008;31(12):2281-2283. PMC
- Lad U, Lad V. Food Guidelines for Basic Constitutional Types, from Ayurvedic Cooking for Self-Healing, 2nd ed. The Ayurvedic Institute. ayurveda.com
This page is for information only and is not medical or dietary advice.