In the news: 50th Anniversary of Landmark Omega-3 Discoveries

50th Anniversary of Basic Omega-3 Discoveries

It has been fifty years since the Danish medical researchers Hans Olaf Bang and JØm Dyerberg published their first landmark paper on the traditional Inuit people of Greenland in 1971 – findings that led to omega-3’s evolving role in human health.

The prevailing mindset in the 1960’s was that all dietary fat was unhealthful and should be kept to a minimum for weight management and cardiovascular health. During this period Ancel Keys and others were just beginning to highlight the links between diet, serum cholesterol and risk of heart attack.

Against this backdrop, Bang and Dyerberg became fascinated with the Inuit who consumed a very high fat diet (primarily whale and seal blubber and fatty fish) yet had virtually no incidence of acute heart attack. They began to explore this apparent outlier population.

The investigative paths that led these Danes to establish one of the most impactful research areas in last half century is chronicled by noted omega-3 experts in the May issue of Nature Food (1).

As the authors point out, the level of scientific interest in the omega-3s is put into perspective by noting that of the most researched molecules in medical history, the omega-3s are essentially tied for 5th place with folic acid, after penicillin, aspirin, vitamin D and prednisone.

Bang and Dyerberg’s 1st paper focused on plasma lipids and lipoproteins. Why did they observe high levels of dietary animal fat but rather low levels of plasma cholesterol in the Inuit? They knew that the Inuit diet provided large amounts of polyunsaturated fatty acids (PUFA), and they theorized that total PUFA or perhaps specific fatty acids in the Inuit’s diet were reducing atherosclerotic risk.

Their 2nd paper (1975) focused on comparing plasma fatty acids in Greenland Inuit eating a traditional diet to Inuit living in Denmark and white Danes. They found low levels of linoleic acid (the major omega-6 poly-unsaturated fatty acid) in native Inuit – a finding that contradicted their initial idea that total PUFA was responsible for the observed low blood cholesteroland triglyceride levels in Inuit. However, Bang and Dyerberg’s seminal observation was that native Inuit had high blood levels of the omega-3 fatty acids EPA and DHA while the Inuit who had migrated and white Danes did not.

By the time that their 3rd paper was published in 1978, other investigators had identified potent molecules (e.g., thromboxane, prostacyclin) that regulate platelet aggregation, vessel constriction, and play important roles in coagulation and the vessel blocking clots of thrombosis.

The Danes proposed that EPA could reduce heart disease risk not just by affecting cholesterol levels, but by also by its anti-thrombotic actions when converted to the series 3 anti-aggregatory eicosinoids. The idea that fatty acids could affect cardiovascular pathways beyond cholesterol was eye opening and led to a surge of research into the anti-inflammatory, heart rate lowering, and pro-resolving properties of EPA/DHA.

Omega-3 Research Continues, Intake Lags

These unique nutrients have been found to play important roles in cardiovascular risk, the resolution of inflammation, and early life brain and eye development. The omega-3 may also contribute to other conditions: neurocognitive disorders including Alzheimer’s, depression, and ocular disorders.

Despite widespread public awareness of omega-3, many Americans apparently do not include sufficient amounts in their diet. In an analysis(2) of National Health and Nutrition Examination Survey data, serum levels of long-chain omega-3 were compared with levels associated with consuming the recommended amount of EPA and DHA by the Dietary Guidelines for Americans and the Omega-3 Index (EPA+DHA). Low serum levels of EPA, DHA and sum of omega-3 were observed across all life stages, with particularly low EPA and/or DHA serum levels seen in children aged 2-5, adult males, and Mexican American /Hispanic and non-Hispanic Black individuals.

References

1. Harris WS, et al. Bang and Dyerberg’s omega-3 discovery turns fifty. Nature Food. 2:303-5, 2021.
2. Murphy R, et al. Long-chain omega-3 fatty acid serum concentrations across life stages in the USA: an analysis of NHANES 2011-2012. BMJ Open.11:e0433301, 2021.