Nutritional quality
Macronutrient content
The literature highlights both the high nutritional quality of algae, and the need for further studies on the specific nutritional profile of different varieties, the bioavailability of the nutrients they contain, and how those vary depending on modes of production and processing.[1]
The digestibility of proteins found in macroalgae is generally low,[2] whereas that of proteins found in microalgae is inferior to that of milk proteins.[3]
Thanks to their dietary fiber content, the potentional for algae to contribute to gut health is perceived as high, although research into this matter is ongoing. Their fat content is low, and they contain healthy fatty acids in high concentrations.[4]
Micronutrient content
Algae present high vitamin and mineral content relative to conventional protein sources. They are particularly high in A, K, and B12 vitamins. While Vitamin B12 is high in macroalgae and microalgae, that found in Spirulina is in a form not absorbable by the human body.[5]
Seaweeds are also high in magnesium, calcium, iron and iodine, which enables their contribution as supplements to the human diet.[6]
Sugar kelp in particular has a high iodine content, and some concern has been expressed that consumers could be getting excessive iodine if kelp was to become a common staple.[7]
Trials of the integration of algae as a supplement in feed have shown that it can contribute to animal diets (with different types of algae proving useful to different species), although palatability issues (which is due to the high mineral content) may limit that potential.[8]
Processing, and particularly blanching, can lead to losing some minerals and soluble carbohydrates.
[1] “[D]espite highly accurate and precise analytical determinations of food content, current knowledge of the nutritional or functional food value of algal products remains largely qualitative”, in Wells ML, Potin P, Craigie JS, Raven JA, Merchant SS, Helliwell KE, Smith AG, Camire ME, Brawley SH, ‘Algae as nutritional and functional food sources: revisiting our understanding’, J Appl Phycol 29 (2):949-982, 2017. doi:10.1007/s10811-016-0974-5.
[2] Bikker P, Stokvis L, van Krimpen MM, van Wikselaar PG, Cone JW, ’Evaluation of seaweeds from marine waters in North-western Europe for application in animal nutrition’, Anim Feed Sci Technol 263:114460, 2020; Krogdahl Å, Jaramillo-Torres A, Ahlstrøm Ø, Chikwati E, Aasen I-M, Kortner TM, ’Protein value and health aspects of the seaweeds Saccharina latissima and Palmaria palmata evaluated with mink as model for monogastric animals‘ Anim Feed Sci Technol 276:114902, 2021; Øverland M, Mydland LT, Skrede A, ’Marine macroalgae as sources of protein and bioactive compounds in feed for monogastric animals‘ J Sci Food Agric 99:13–24, 2019.
[3] Parodi et al., 2018.
[4] Barbier et al. PEGASUS - PHYCOMORPH European Guidelines for a Sustainable Aquaculture of Seaweeds, COST Action FA1406 (M. Barbier and B. Charrier, Eds), Roscoff, France, 2019. https://doi.org/10.21411/2c3w-yc73.
[5] Parodi et al., 2018.
[6] Barbier et al., 2019.
[7] EFSA, Dujardin B, Ferreira de Sousa R, Gomez Ruiz JA, ’Dietary exposure to heavy metals and iodine intake via consumption of seaweeds and halophytes in the European population’, EFSA Journal, 2023, 21 (1):e07798. doi:https://doi.org/10.2903/j.efsa.2023.7798.
[8] Ibid.