Alpha to Omega 3 - Securing EPA & DHA supply
Marine omega-3 fatty acids, EPA and DHA, are an essential part of healthy diets for both humans and fish. The growth in global aquaculture has increased the demand for EPA and DHA to levels where supply can no longer meet demand. Developing new sources and avoiding waste can help.
Mapping the EPA & DHA balance
It is common knowledge that eating seafood is good for you. It contains healthy omega-3 fatty acids, such as EPA and DHA, which are essential for neurological and visual development in infants and provide a range of cognitive and cardiovascular benefits for adults.
On average, the Global Organization for EPA and DHA Omega-3s (GOED) recommends an intake of 500 mg of EPA and DHA per day, sourced primarily from fish and marine supplements. However, when estimating the total EPA and DHA supply, only 30% of the world population gets what they need. This can have a severe impact on global human health. The reasons for the supply gap are numerous - but improved waste recycling, tapping into new sources, and changing diets to favour more seafood are all options to boost the omega-3 supply.
Material Flow Analysis
Material flow analysis (MFA) is an analytical tool that tracks and quantifies the consumption and losses of materials or substances within a defined system in order to identify strategies to optimize their use.
Figure 1. Global EPA and DHA balance adapted from Hamilton et al., 2020. Blue arrows show values of EPA + DHA per year in kilo tonnes
(kt). Mass balance inconsistencies are due to rounding errors and uncertainty. FM&O, fish meal and oil; FO, fish oil; NPP, net primary
production. Blue circle indicates biological production of EPA and DHA by fish.
Fish stocks
On average, all fish stocks are considered fully exploited and have been so for 30 years. We cannot harvest more from the ocean, which makes wild fish an unviable source for extra EPA and DHA. This means that we must better manage the EPA and DHA that we already have or find new sources. To figure this out, first, we need to know how EPA and DHA are produced and consumed by humans and in the ocean. One untapped source is krill. Krill, which is high in EPA & DHA, represents the largest standing biomass in the world. Despite the sizable available biomass, krill is currently harvested at approximately 5% of the total allowable catch (TAC) of 5.6 million tonnes per year.
Aquaculture can increase supply
Aquaculture can increase the omega-3 supply but some species, such as salmon, require fish meal and fish oil in their diets. If these fish do not get enough EPA and DHA, it negatively affects their health and reduces the omega-3 fatty acids they contain. Despite aquaculture being the largest consumer of EPA and DHA, it is also a producer through species like molluscs and carp which can biologically prolong shorter chained fatty acids into EPA and DHA.
Waste and novelties
Fish feed and fish oil can be made from fish waste and trimmings, if the waste can be collected and processed. In Europe and North America, fish are gutted and processed by industry, which makes it easy to collect and reuse by-products. However, in Asia, large amounts of food waste are generated by households making it difficult to use the waste for anything useful. Asia has, by far, the largest potential for increasing omega-3 supply by reducing and recycling waste.
New, novel sources of EPA and DHA include microalgae, bacteria and modified plants. These products are now being rapidly scaled up for intensive production and are showing economic viability. Along with undergoing measures on modified crops, these novel solutions will offer new omega-3 sources and help to close the supply gap. There is no silver bullet for closing the supply gap and none of the strategies are easy. But we must find a way to balance healthy human nutrition, a growing
population and protecting our environment.
Reference: Hamilton, H.A., Newton, R., Auchterlonie, N.A. et al. Systems approach to quantify the global omega-3 fatty acid
cycle. Nat Food 1, 59–62 (2020). https://doi.org/10.1038/s43016-019-0006-0