Lab-grown algae could provide more environmentally friendly alternative to fish oils, scientists suggest

The omega-3 fatty acids found in food substances such as some types of fish have long been held to play an important role in human diet.

This is one reason why the NHS currently recommends people eat “at least two portions of fish a week, including one of oily fish”. Oily fish are particularly rich in omega-3.

In addition to being widely regarded as an important part of a well-rounded diet, omega-3 has previously been credited with boosting cognitive function and protecting the heart, though recent research has not supported these claims.

Nonetheless, global demand for omega-3 fish oil supplements was valued at $2.49 billion in 2019, and the market is forecast to continue expanding.

The rise in demand comes amid growing concern about the impact of overfishing and fish farming techniques.

But scientists at Martin Luther University of Halle-Wittenberg in Germany have suggested microalgae could provide an alternative source of healthy omega-3 fatty acids for humans while also being more environmentally friendly to produce than popular fish species.

The study was recently published in the Journal of Applied Phycology and offers an initial indication of the environmental effects of producing microalgae in Germany.

Microalgae have been the focus of several decades of research — initially as a raw material for alternative fuels, but more recently as a source of nutrients in the human diet. They are mainly produced in open ponds, but according to the German researchers, these ponds are at risk of potential contamination. Also, some species of algae are easier to cultivate in closed systems, so-called photobioreactors.

“We wanted to figure out whether microalgae produced in photobioreactors in Germany could provide a more environmentally friendly source of essential nutrients than fish,” said Susann Schade from the Institute of Agricultural and Nutritional Sciences at MLU.

Previously photobioreactors had usually only been compared to pond cultivation and they often scored worse due to their higher environmental impacts.

“However, little research has been done on the precise extent of the environmental impacts of algae produced for human consumption, especially under climatic conditions such as those found in Germany,” Ms Schade added.

“One of the things we did was to compare the carbon footprint of nutrients from microalgae and fish. We also analysed how much both food sources increase the acidification and eutrophication in water bodies,” said Dr Toni Meier from MLU.

The researchers said they were able to show microalgae farming has a similar impact on the environment to fish production.

“However, if we compare the environmental effects in relation to the amount of omega-3 fatty acids produced, fish from aquaculture (farmed fish) comes off far worse,” said Ms Schade.

The researchers said one advantage of algae cultivation is its low land consumption. Even infertile soils can be used.

In contrast, both open ponds and the cultivation of feed for aquaculture require very large areas of land. In particular, fish species that are popular in Germany, such as salmon and pangasius, are primarily produced through farming and therefore put the environment under a considerable amount of pressure.

Despite the findings the research team said their microalgae should not been seen as a wholesale replacement.

“Microalgae should not and cannot completely replace fish as a food source. But if microalgae could be established as a common food, it would be another excellent environmentally friendly source of long-chain omega-3 fatty acids,” said Dr Meier.

But the researchers said it could be a way to reduce the current gap in the global supply of omega-3 fatty acids. At the same time, they claim this could provide “considerable relief” to the world’s oceans.