Omega-3 fatty acid heart benefits still unproven after decades of research

In the 1970s, a pair of Danish researchers ventured north of the Arctic Circle and into medical lore. Studying a scattered Inuit population, they concluded that eating plenty of fish and other marine animals protected this group from heart disease.

The researchers would eventually suggest that everyone else's hearts and arteries might also benefit from the "Eskimo diet", promoting a health food trend that continues to this day.

The only trouble is, Hans Olaf Bang and Jorn Dyerberg never proved the Inuit had low rates of heart disease. They never tested it at all. But today the market for fish oil pills is booming, even as scientists conduct trial after trial to hunt for a link to heart health that has never quite solidified.

Bang and Dyerberg were clinical chemists at Aalborg in Denmark. Curious about the nutrition of the Inuit, they "undertook an expedition" to the northwest coast of Greenland, which they described in a 1971 Lancet paper.

They stopped at a town called Uummannaq. Counting the surrounding settlements, the population totalled 1,350 people, living off what they could hunt and fish from the unforgiving land.

The researchers drew blood from 130 natives. Compared to Danes, the Inuit had lower levels of lipids such as cholesterol and triglycerides. Yet they had a higher proportion of the molecules known as omega-3 fatty acids, which are common in oily, cold-water fish.