Seaweed is touted as the miracle food: it’s sustainable, it’s healthy, and it’s plentiful. Here is my take on seaweed, and why it hasn’t saved the world yet.
1. We should eat seaweed because it’s healthy. But we don’t.
Seaweed is excellent for human health (unless you have a thyroid disorder). It’s chocked full of micronutrients that are commonly deficient. Most famously, it has a lot of iodine, which most of the world is so deficient in, that governments make it illegal for salt producers to not iodize their salt. It also is rich in a highly bioavailable form of magnesium, increasingly depleted in terrestrial-sourced vegetables due to poor soil quality and over-intensification of mono-crops. It’s high in iron, a lack of which is responsible for worldwide anemia, particularly for women and across all socio-economic demographics. It’s also a good source of calcium.
But no matter how good something is for us, we are creatures of habit. Encouraging consumers to make food substitutions is complex, and most consumers won’t be adventurous. I’ve actively tried to include more seaweed in my diet but failed because my store doesn’t always have it… It’s expensive… I’m not used to cooking it… I don’t know how to include it in recipes… etc. These are all seemingly simple things to overcome, but still require effort, which may be too great for even the most conscientious of consumers.
The idea of putting it into convenience foods, like burgers, is genius – we need more of this. And yet, even with that, there will be the “ick” factor – insects are the most sustainable, lean, high-quality source of protein in the world. Yet, we don’t eat them because of cultural taboos. This also exists for seaweed, though to a lesser extent due to the popularity of sushi and Japanese foods driven by Hollywood celebrities in the 1960s and 70s.
2. Intensifying production from current sources of seaweed would not sustainable.
If we DID manage to encourage consumers to eat more seaweed, where would we get it from? Seaweed for pharmaceuticals (toothpaste & other products containing carrageenan) is typically grown in high-tech tubes for biosecurity. Very sustainable, but expensive. We get most of our seaweed for food & construction via seaweed harvesting (from wild sources). By ‘we’, I mean everyone except those in China and Japan, who have industrial-scale high-tech farms due to local demand. For now, demand is so low that harvesting it is sustainable – it replenishes itself fairly well if managed properly. But increased harvest would destruct diverse coastal ecosystems with implications such as coastal erosion, fisheries depletion, and other ecosystem benefits.
If demand were to increase, we’d need to increase seaweed farming. Yet, seaweed farming has major social problems. Currently, seaweed farming is mostly done in lower-income countries so harvesting can be done manually. Seaweed farming in Zanzibar, promoted for poverty alleviation, may not be worth the poor working conditions. In Phillippines and Indonesia, poor farmers often operate under loan sharks, where a seaweed farmer borrows some money from a loan shark to recuperate losses after a bad storm, but the farmer ends up “paying him back” for the rest of their life.
We could address this with better technology; however, high-tech production would probably eliminate margins at the current price point, and seaweed is already an expensive vegetable. Ultimately, consumers will be driven by price – why pay for seaweed when I could buy kale for less than half the price? Particularly if there are additional barriers to consumption (as mentioned above)?
3. Mass-scale production of seaweed as bioremediation isn’t economically feasible.
Many academics think IMTA (integrated multi-trophic aquaculture) is the future, where waste from salmon farms is absorbed by surrounding seaweed crops and benthic animals like bivalves and sea cucumbers. A lot of research is going into the technology of how to make it work as a way to sustainably intensify aquaculture production. They praise seaweed as this miracle product – it removes nitrogen from the water (produced by intensive fish farms), producing nutrient-rich food for consumption – what’s not to love? Why not plant seaweed around EVERY fish farm to soak up the waste?
Firstly, it would take ACRES of seaweed to deal with all the nutrient runoff from just one fish cage. Equipment and infrastructure for harvesting it is costly, and, beyond our models, we don’t have any actual evidence of economic viability. There just ain’t no one making it work yet.
Secondly, what do you do with all that seaweed? Even Japan, the country with the highest per capita seaweed consumption in the world, consumes less than 2kg/year/person. It could go to other uses, like livestock feed or pharmaceuticals. But even then, the quantities just don’t align. Furthermore, most of the seaweed isn’t high enough grade for pharmaceuticals.
It’s a really interesting sector that offers so many opportunities, but in reality, it always comes down to the money, honey!
References For Further Reading
Bizzaro, G., Vatland, A.K. and Pampanin, D.M., 2022. The One-Health approach in seaweed food production. Environment International, 158, p.106948.
Cherry, P., O’Hara, C., Magee, P.J., McSorley, E.M. and Allsopp, P.J., 2019. Risks and benefits of consuming edible seaweeds. Nutrition Reviews, 77(5), pp.307-329.
Circuncisão, A.R., Catarino, M.D., Cardoso, S.M. and Silva, A., 2018. Minerals from macroalgae origin: Health benefits and risks for consumers. Marine Drugs, 16(11), p.400.
Fröcklin, S., de la Torre-Castro, M., Lindström, L., Jiddawi, N.S. and Msuya, F.E., 2012. Seaweed mariculture as a development project in Zanzibar, East Africa: A price too high to pay?. Aquaculture, 356, pp.30-39.
Knowler, D., Chopin, T., Martínez‐Espiñeira, R., Neori, A., Nobre, A., Noce, A. and Reid, G., 2020. The economics of Integrated Multi‐Trophic Aquaculture: where are we now and where do we need to go?. Reviews in Aquaculture, 12(3), pp.1579-1594.
Kurlansky, M. 2002. Salt: A World History. New York, NY: Penguin Group.
Lomartire, S. and Gonçalves, A.M., 2022. An Overview of Potential Seaweed-Derived Bioactive Compounds for Pharmaceutical Applications. Marine Drugs, 20(2), p.141.
Makkar, H.P., Tran, G., Heuzé, V., Giger-Reverdin, S., Lessire, M., Lebas, F. and Ankers, P., 2016. Seaweeds for livestock diets: A review. Animal Feed Science and Technology, 212, pp.1-17.
Stull, V.J., 2021. Impacts of insect consumption on human health. Journal of Insects as Food and Feed, 7(5), pp.695-713.
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