Identifying new sustainable and efficient sources of omegas beyond marine source is of paramount importance . Chris Gearhear of The Global Organization of Omega 3s EPA and DHA ( GOED ), told us in 2022 that “ The stakes are high . The oceans can ’ t provide even the most conservative daily dose of EPA and DHA for each human being .” Marine oils pose significant environmental challenges , with research attesting to the severe depletion of fish stocks , and some researchers suggesting we could see virtually empty oceans within the next few decades .( 4 )
Ocean toxicity is of growing concern , with a study of 12,000 food and feed samples by the European Food Safety Authority determining fish and fish oil to be the highest in PCB contamination . ( 5 ) Heavy metals , microplastics , and dioxins are additional concerns in many marine-derived products .( 6 ) It has been suggested that persistent organic pollutants are implicated with metabolic disease risk , which may elucidate the mixed literature on clinical outcomes associated with fish and fish oil consumption .( 7 )
As a more sustainable and less contaminated source of LCPUFAs , algal oils have been rapidly rising in popularity . However , most currently available are vastly dominant in DHA rather than EPA , and research using compound-specific isotope ratio analysis demonstrates that so-called ‘ retroconversion ’ to EPA and other precursors does not occur at any meaningful level , and that instead rises in EPA levels following DHA supplementation are a consequence of a slowed conversion / pooling of EPA .( 8 ) Further , recent research shows that we downregulate our body ’ s natural omega-3 metabolism pathway from plant-based precursors ALA and SDA when we supplement with preformed DHA .( 9 )
Flax , chia , hemp and dark green leafy vegetables are plant-based omega-rich sources that provide the essential omega-3 ALA . Omega-3 ALA ’ s
Figure 1 .
conversion through to the LCPUFAs is considered inefficient in many people , although it is known that vegans and vegetarians have increased conversion through to EPA in the blood , and that , compared to their omnivorous counterparts , their DHA precursor : product ratios are greatly upregulated . ( 10 ) Other factors influencing the efficiency of this conversion pathway and ALA ’ s ability to meet LCPUFA needs include diet , age , gender and genetic variabilities , such as SNPs .
The shared rate-limiting step determining conversion of omega-3 ALA and omega-6 LA through to their more advanced omega metabolites is called the delta-6-desaturase ( D6D ) enzyme .( 11 ) The astounding imbalance between omega-6 and omega-3 found in the typical Western diet – driven by ubiquitous industrial commodity oils like palm , corn and soya – contributes to the rate of inadequacy of this natural metabolism pathway . Furthermore , high consumption of animal products and processed plant foods provides far higher omega 6 : omega 3 ratios than is considered biologically optimum . Competition between omega-3 and omega-6 at the D6D step hinders omega-3 ALA conversion and may lead to inadequate EPA and DHA provision .
The metabolism of Omega 3 and Omega 6 fatty acids is summarised in Figure 1 .
Omega-3 SDA - The efficient plant-derived EPA precursor
Omega-3 SDA proceeds ALA and the rate-limiting D6D step in the omega-3 metabolism pathway , raising EPA levels in the blood efficiently- showing a greatly enhanced conversion rate of approximately 30-40 %.( 12-14 ) Due to SDA bypassing this competitive enzyme , it is able to convert through to the entire spectrum of omega-3s , even when background omega-6 LA intake is high , as seen in most patients following a Western diet .( 12 )
Currently the best-known plant source of omega-3 SDA is hemp , providing around 2 % SDA . However , refined Buglossoides arvensis seed oil is the richest known source of polyunsaturated fatty acids , and the highest known natural plant source of omega-3 , including SDA .( 15 , 16 ) Its ~ 20 % SDA content would allow us to meet current global omega-3 requirements on only 480,000 hectares per year- just 1.3 % of the number of soybean hectares recorded in the US in 2017 , and overwhelmingly designated to animal feed .
JATMS | Summer 2024 | 219