Can you eat seaweed

Eating seaweed: healthy or dangerous?

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These healthy nutrients are found in the most popular types of algae

A look at the ingredients shows that algae definitely have the potential to be a healthy “vegetable”.

Algae are consistently high due to their high water content and low fat content low in calories.

Also contain green algae Chlorophyll - a green dye that has an antioxidant effect, ie protects against harmful intermediate products of our metabolism (so-called "free radicals"). By the way, chlorophyll is also found in green vegetables such as spinach or broccoli.

How many nutrients there are in an alga, however, depends on the respective variety. Because not all algae are the same.

According to experts, there are said to be more than 500,000 species of algae.

So far, of these are just once 500 used by humans - and again only part of it is permitted as food.

If you want to try cooking with algae, I recommend our kohlrabi spaghetti salad with wakame. Photo: SevenCooks

A general judgment about algae cannot be made. So let's take a closer look at the species that end up on our plates most often.

What nutrients do they contain in noteworthy quantities?


The comparatively low-iodine freshwater algae are rich in beta-carotene, calcium and iron. It also contains the “vegan vitamin” B12 (attention: whether vitamin B 12 from algae can be used by humans is controversial).

Kombu (Kelpe):

The kombu alga has a high iodine content in the mix with relevant amounts of calcium, iron and beta-carotene.


The aromatic red alga provides an extra portion of calcium, magnesium, phosphorus and zinc. In addition, there are relevant amounts of iodine and vitamin A.


This type of algae convinces with plenty of calcium, magnesium and phosphorus. The same applies to vitamins A, C and E as well as B vitamins. It also contains relevant amounts of iodine. The special thing about it: Wakame contains a high content of vitamin B12.


The low-iodine green algae provides plenty of magnesium, calcium, vitamin A, vitamin C and vitamin B12.

Why exact nutritional information is impossible

The content of valuable ingredients varies not only according to the variety, but also according to the water quality, according to the Federal Center for Nutrition. This aspect affects both wild algae in their natural environment and cultivated algae.

In addition, the time of harvest, other environmental influences and drying also influence the micronutrient content.

It is therefore not possible to give exact information on the content of iodine and co.

In other words: the algae on your plate can deviate significantly from values ​​that you may find on the Internet.

Reading tip: Here I'll show you how to cook with seaweed.

Are algae a good source of iodine?

Meeting your iodine requirements with algae is difficult. One of the reasons for this is that the exact iodine content difficult to determine from algae (see Why exact nutritional information is impossible).

If you want to do it, you should only use algae products that controlled according to EU standards and their iodine content is noted on the packaging.

It is not advisable to use many products from Asia that are not strictly controlled.

Because the iodine content of algae products can sometimes be very high. According to the consumer advice center, deliver dried algae products from 5 to 11,000 (!) Micrograms. With such a large amount, 0.02 grams of dried algae already exceeds the needs of the average adult.

Algae can be a delicious ingredient, as in our miso soup, but as a source of iodine they are only partially recommended. Photo: SevenCooks

Especially with people with Thyroid disease high iodine intake can be risky. Therefore, I advise you to avoid algae products as much as possible at Hashimoto and Co.

Against an occasional, moderate enjoyment In my opinion, however, nothing speaks about low-iodine varieties such as nori algae or ulva. You can also reduce the iodine content by washing and soaking.

Do algae contain heavy metals and other pollutants?

The iodine content isn't the only thing to look out for when buying and consuming seaweed.

Since they filter toxins from the water, algae, like fish, can be contaminated with pollutants and heavy metals.

It is therefore possible that with a regular consumption of larger amounts of algae Mercury, lead and cadmium accumulate in your body. The same applies to aluminum and arsenic. For this reason, you should definitely only serve algae taking my buying tips into account.

In addition, it cannot be ruled out that in cultivated algae in addition bacteria and collect harmful algae species in the breeding tanks. This is especially true for products that lack strict controls.

Danger: I advise against food supplements with algae, because concentrated amounts of pollutants and maximum amounts of iodine can be absorbed.

Are Algae a Good Source of Vitamin B12?

Some algae contain significant amounts of vitamin B12. That is what she does Vegans popular who have to supplement this substance. These include the macroalgae wakame and nori, but also ulva.

The same applies to food supplements based on microalgae Chlorella and Spirulina. (The other algae presented in this text are negligible in terms of their vitamin B12 content.)

According to the consumer advice center, however, it is not certain whether the vitamin B12 contained in algae can contribute to human nutrition.

It is believed that these are so-called Vitamin analogs acts that cannot be used by the human body.

Reading tip: As a vegan, I would strongly recommend that you cover your vitamin B12 with special dietary supplements, fortified foods and the like until proven otherwise. I explain how to do this in my article on vitamin B12.

Conclusion and buying tips for algae products

Can algae be part of your menu on a regular basis? Yeah, but I wouldn't overdo it.

As an orientation I adhere to, for example weekly sushi meal - provided that the ingredients are of high quality - or occasional seasoning with algae flakes as unproblematic. I would definitely advise against serving seaweed products on a daily basis.

So that nothing stands in the way of the occasional enjoyment of algae in the form of sushi, miso or ramen soup, please note the following tips for buying algae. Then you can use the included Micronutrients benefit - and avoid health risks from excess iodine or pollutants.

My algae buying tips:

  • Only buy algae products on which the iodine content is specified precisely (not mandatory, but some manufacturers give this important note)
  • Prefer organic quality algae
  • Only buy algae that state a maximum consumption amount (also not mandatory, but some manufacturers give this important note)
  • Refrain from buying algae both online and in grocery stores if the origin and control are unclear

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Cover picture: SevenCooks