CEVA (Algae Technology and Innovation Centre) lists all the analyses it can do on seaweed through projects and the data published in the scientific literature in a database. This database enables one to create summary sheets showing the average composition of nutrients by seaweed with an indication of the min and max values and the number of references.

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Seaweed is considered to be a ‘novel food’ in the eyes of the European regulations. So anything that has not been authorised/approved or was not consumed significantly in Europe before May 1997 cannot be consumed/marketed as a food. France issued an initial list of seaweed that can be eaten in the 1990s which has been extended over the years. The European commission also keeps a list up to date that includes the species that have been assessed in Europe as not being ‘novel’. (find out more).

This does not mean that the other seaweed are not edible but in regulatory terms it is necessary to have an authorisation from EFSA or prove that it was consumed before 1997 on European soil.
But are all seaweed edible? There is no seaweed that is venomous as some mushrooms can be. However, some seaweed are very rich in active compounds, such as bromoforms, which can be toxic in high doses.

There is no maximum daily dose of seaweed allowed per day.
It is commonly established that a reasonable portion of seaweed consumption is around 5 to 7 g/day (dried seaweed or equivalent). If you eat it every day, it amounts to 1.8kg-2.6kg of dried seaweed/year/person. That is quite a lot!
The Japanese eat between 10-15g dried/day/person.

Certain brown seaweed are very rich in iodine. Can you still eat them?
Macro-algae’s iodine richness is above all a nutritional benefit in seaweed which is very important worldwide in light of the risks relating to an iodine deficiency. Iodine is essential for the organism which concentrates it in the thyroid.
However, the fact that seaweed’s exceptional richness in iodine may become problematic in the event of excess has always been a concern for the supervisory authorities, as well as stakeholders in the seaweed industry. Therefore, at the end of the 1980s, the French authorities laid down maximum iodine content that must be observed as well as reduced consumption doses for certain seaweed (laminaria). Over time, these recommendations have changed to establish a maximum iodine threshold of 2,000 mg/kg dried seaweed (find out more)
In the nutritional references for vitamins and minerals published by ANSES in 2021, it is indicated that:
• the adequate iodine intake is 150 µg/day for adults
• the upper intake level is 600 µg/day

It seems important to us to formulate products with these limits in mind and not to offer consumers food in portions that would exceed the UL.

To grasp seaweed’s incredible richness and take advantage of its organoleptic and nutritional benefits without risking excessive iodine intake, there are several strategies to consider:
• It is important to vary the species of seaweed consumed and to regulate consumption of it to avoid the risk of excess.
• Certain stakeholders, and CEVA in particular have also demonstrated the possibility of using traditional agri-food processing to reduce this content:
o Since 2013, CEVA has suggested blanching seaweed for 45 seconds approximately in sea water or fresh water to wash 80% of the iodine out (Marfaing et al, 2013).
o Macerating seaweed in warm water also reduces the initial iodine content by 50 to 80% (Stévant et al, 2018).
o Salting and sterilisation treatments can also reduce iodine in seaweed.

The heavy metal and contaminant content in seaweed depends on the species and the environment it grows in. The French recommendations established from the end of the 1980s since the beginning of seaweed consumption are very strict and advise very low thresholds. Given the portions consumed and the thresholds that must not be exceeded, seaweed is far from being a risky food or a major contributor of heavy metals to our diet.

Not all seaweed is rich in protein and a daily seaweed consumption of 5-7g/day can only contribute part of the 48-56g/day of protein recommended for an adult by the WHO. Currently, seaweed cannot replace meat and fish but can supplement the intake of land vegetables.
Eventually, with the development of selection, the growing conditions and post-harvest pre-treatment, we can also envisage macro-algae that is richer in protein to supplement a diet.
With micro-algae, the raw materials can be very beneficial in terms of protein, but the production volume is still low and it is not always easy to incorporate it in food. With extraction, we could also envisage concentrated protein developments in future as is the case today with many land vegetables.
But the seaweed matrix does not just involve the potential of proteins. Above all, it is a very beneficial matrix due to its nutrient complexity and richness.