Maria Jacobsen1, Ellen Ahlgren2, Marta Angela Bianchi1, Susanne Bryngelsson1, Elinor Hallström1, Sara Hornborg1, Jean-Baptiste Thomas2, João Trigo3, Ingrid Undeland3, Friederike Ziegler1
1RISE Research Institutes of Sweden, Gothenburg, Sweden
2Department of Sustainable Development, Environmental Science and Engineering (SEED), KTH Royal Institute of Technology, Stockholm, Sweden
3Department of Biology and Biological Engineering–Food and Nutrition Science, Chalmers University of Technology, Gothenburg, Sweden
The climate effects of farmed seaweeds is a hotly contested topic with numerous knowledge gaps regarding their nutritional and health benefits. This study reviews the climate and nutrition performance of farmed sugar kelp, in comparison with reference foods, e.g. herbs, vegetables and meat products. Cradle to farm-gate climate impacts were recalculated using harmonized methodologies and life cycle inventory data from 6 LCAs published between 2012-2020. Data on the nutritional content of unprocessed and whole dried sugar kelp was collected in a systematic literature review in Sep 2021, then aggregated into nutritional density scores based on the Nutrient Rich Food Index (NRF11.3, 21.3).
Results show that sugar kelp has a high nutrient density and a low climate impact relative to many other common foods such as meats, vegetables and herbs. However, the estimations neither account for nutrient bioavailability nor for effects from processing such as drying, blanching or up-concentration of proteins. Further studies are warranted to determine the effect of processing on nutrient density and carbon emissions. Though the climate impact is low compared to other foods, typical portions of sugar kelp in western diets remain very small and it is not yet clear what type of food it can be compared to, so one must be careful suggesting climate benefits can be achieved by substituting other common foods. This review contributes to consolidating the potential of seaweed as a nutritious and low impact food source in future diets.