Heart Health

Original Oily Fish Study Flawed

You’ve heard it here on ThirdAge and probably elsewhere as well: Oily fish such as salmon, fresh tuna, and swordfish are currently recommended as part of a heart healthy diet. Oops! An international team of researchers have called into question the validity of a now-classic study from the 1970s that claimed that because the diet of Eskimos in Greenland is rich in whale and seal blubber, these peopledon’t have coronary artery disease at the same rate as other populations.On the contrary, the Eskimos turn out to have alarmingly high rates of lethal CAD and stokes. The new study was done by investigators at the University of Ottawa Heart Institute in Canada, Martin Luther University in Germany, and Slovak Medical University in Slovakia andpublished online in April 2014 inthe Canadian Journal of Cardiology.

A release from the publishers quotes lead investigator George Fodor, MD, PhD, FRCPC, FAHA as saying"Considering the dismal health status of Eskimos, it is remarkable that instead of labeling their diet as dangerous to health, a hypothesis has been construed that dietary intake of marine fats prevents CAD and reduces atherosclerotic burden."

The original study, done by the Danish researchers Bang and Dyerberg, connected the low incidence of coronary artery disease (CAD) among the Eskimos to what they typically ate but the current study reports that the authors found that the Eskimos actually suffered from CAD at the same rate as their Caucasian counterparts, meaning there is insufficient evidence to back Bang and Dyerberg's assertions.

Using 40 years of new information and research, the team set out to reexamine Bang and Dyerberg's study, which is still widely cited today and is the origin of the practice of recommending the dietary addition of fish oil supplements with omega-3 fatty acids or oily fish to help avoid cardiovascular problems. However, the new review of information has determined that Bang and Dyerberg actually failed to investigate the cardiovascular health of the Eskimo population, meaning that the cardioprotective effects of their diet are unsubstantiated.

"Bang and Dyerberg's seminal studies from the 1970s are routinely invoked as 'proof' of low prevalence of CAD in Greenland Eskimos ignoring the fact that these two Danish investigators did not study the prevalence of CAD. Instead, their research focused on the dietary habits of Eskimos and offered only speculation that the high intake of marine fats exerted a protective effect on coronary arteries," Dr. Fodor said.