The Study
Scottish Seaweeds as Sustainable Sources of Micronutrients: Mineral Composition, Vitamin B12 Content, and Safety Assessment
This study didn't test if eating seaweed makes people healthier—it just checked how many vitamins and metals are in different kinds of seaweed from Scotland. It's like counting how many candies are in different jars, but not seeing if eating them makes you happier or sick.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Some seaweed from Scotland has vitamin B12 like meat, but also too much iodine and a dangerous form of arsenic.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This means seaweed could help vegetarians get B12, but eating it raw or too often is dangerous—unless you boil it first.
- 2A 5g piece of Fucus serratus seaweed gives you almost half your daily B12.
- 3But it also has 10x more iodine than you should eat in a day.
- 4Laminaria digitata has so much toxic arsenic that eating it weekly could raise cancer risk.
- 5Boiling it for 5 minutes cuts iodine by 90% and arsenic by over half.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Food Science & Nutrition
Year
2026
Authors
I. Almosa, Shabina Bashir, A. Sneddon
Related Content
Claims (6)
Eating a 5-gram serving of most Scottish seaweed provides more iodine than the European safety limit of 600 micrograms per day, and one common species, Laminaria digitata, contains over 1,400 milligrams of iodine per kilogram of dry weight, which can lead to iodine intake above safe levels even when consumed once a week.
Farmed Scottish seaweed Alaria esculenta and Saccharina latissima have higher iron content per gram than wild seaweed of the same species, with a 5g portion providing up to 83% of the recommended daily iron intake.
Fucus serratus seaweed from Scotland contains vitamin B12, and eating 5 grams of dried seaweed provides nearly half the daily vitamin B12 requirement for adults.
Heating certain types of seaweed at 80°C for 5 minutes removes up to 90% of the iodine, without removing other nutrients.
Scottish seaweed contains high levels of arsenic, with one common species containing up to half inorganic arsenic, a substance known to cause cancer, and eating 5 grams per week of this seaweed results in exposure levels associated with increased cancer risk.
Vitamin B12 is required for normal human bodily functions and is not naturally produced in usable amounts by plants or fungi.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.