Algae are a group of organisms which occur in most habitats; from oceans and freshwater to deserts and from hot boiling springs to snow and ice. There are between 1 and 10 billion species of algae and they range from very small, single cell forms to large, complex ones; the largest of which are seaweed. Algae have been part of the human diet for thousands of years and some researchers think that eating them may have contributed to ancient human brain development. This is because algae contain many nutrients which have been thought to aid brain development, including essential fatty acids (ALA, DHA and EPA Omega 3), zinc, magnesium, taurine and iodine.
The brain relies heavily on the presence of DHA Omega 3. DHA is important for keeping the brain working efficiently and allowing new connections to be made; this helps us learn and improves memory. Mice who are deficient in DHA and who have been supplemented with an algae-based DHA substitute have shown increases in hippocampal functions (memory and navigation) and in the number of new cells made by the brain.
Algae and seaweed are also high in zinc. Zinc is an essential mineral that supports a healthy immune system, is necessary to make DNA and is essential for wound healing. It is also important during childhood, adolescence and pregnancy to support the healthy growth and development of the body. The main sources of dietary zinc are animal liver, oysters and crustaceans (e.g. crab and lobster); nuts and seeds contain a small amount of zinc but algae and seaweed are by far the greatest plant-based source of this mineral.
Algae is also increasingly being used as an additive in food because of its functional capabilities. The presence of algae in the gut may help increase the ability of the digestive system to access nutrients from other foods we have eaten. However, it is worth considering that not all guts may deal with algae in the same way; algae digestion varies among humans from different regions e.g. Japanese people have more enzymes specifically for breaking down the proteins in algae than American people do. This is thought to be due to food habits (probably that So, aapanese people tend to eat algae more regularly than American people do), diet history, genes and the bacteria present in the gut.
Algae may also have other benefits besides nutrition; they may help contribute to reducing pollution. Heavy metals produced by manufacturing, exhaust fumes, sewage waste and fertilisers can make their way into fresh water and can disturb the ecosystems that exist there and contaminate drinking water. These heavy metals can be taken up by algae so as to reduce the toxins in the water.
Algae may also be able to help support artificial organs by providing them with oxygen for ventilation. Algae have the ability to convert carbon dioxide to oxygen in extremely difficult conditions and therefore may be able to replace implanted ventilation systems in artificial organs.
So, although small in size, algae may represent one of the most important substances for human nutrition and environmental health. Much is still unknown about the benefits of algae and more and more research is being conducted which might help us understand these. Until then, it seems that we should try to include more algae (in the form of spiralling, chlorella and nori) in our diets to make sure we utilise the great nutritional benefits it can provide.
 Cornish, M. L., Critchley, A. T., & Mouritsen, O. G. (2017). Consumption of seaweeds and the human brain. Journal of Applied Phycology, 1-22.
 Wells, M. L., Potin, P., Craigie, J. S., Raven, J. A., Merchant, S. S., Helliwell, K. E., … & Brawley, S. H. (2016). Algae as nutritional and functional food sources: revisiting our understanding. Journal of Applied Phycology, 1-34.