The Fish Stories Behind Fish Oil

Fish oil pills: A $1.2 billion industry built, so far, on empty promises

People in the United States spend about $1.2 billion annually for fish oil pills and related supplements even though the vast majority of research published recently in major journals provides no evidence of a health benefit.
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“Unfortunately, it’s a common situation,” said John P.A. Ioannidis, a professor at Stanford University who has critiqued the methods and findings in nutritional research. Too often, in the view of Ioannidis and colleagues, claims that one food or another has a particular health effect persist long after they have been contradicted by more exacting research.

How did the current situation evolve?

The fish oil story begins with the account of its discovery. In the 1970s, two Danish scientists, Hans Olaf Bang and Jorn Dyerberg, visited remote Inuit villages in northwest Greenland.

The people in those villages ate mostly whale, seals and fish, according to the scientists. While orthodox thinking at the time suggested that a diet so rich in animal fat would cause heart disease, reports of heart attacks there were very few. Bang and Dyerberg were intrigued.

During their visit, they drew blood samples of 130 Inuits. The samples showed low levels of cholesterol and triglycerides, which are viewed as markers of heart disease.

Eventually, the two formally would hypothesize that the low levels of heart disease among the Inuit was caused by the omega-3s in their fishy diets.

One of the first major tests of this idea was published in the British medical journal the Lancet in 1989. The test, often referred to as the DART study, looked at more than 2,000 Welsh men who had suffered heart attack; some were told to eat more oily fish. That group, it turned out, was 29 percent less likely to die over the next two years.

The demand for fish oil was about to grow. Pharmacies and health food stores were stocking up on fish oil supplements in the ’80s, and by the mid-90s, the industry counted sales in the tens of millions.

But it wasn’t until the early 2000s that the market began to soar. In part, the enthusiasm stemmed from the advice from the broadly influential American Heart Association. In 2002, the association issued a “Scientific Statement” concluding that “omega-3 fatty acids have been shown in epidemiological and clinical trials to reduce the incidence of cardiovascular disease.”

The statement, however, was based on mixed evidence. Some of the observational studies at the time showed that eating fish provided a benefit; others didn’t. Two randomized trials showed a benefit, while a third didn’t. At the same time, consuming fish and fish oil didn’t show harmful effects, either.

Bill Harris, one of the three authors of the AHA statement, said that currently the “evidence is unclear” on the benefits of fish oils.

But “it all made a lot of sense at the time,” said Harris, now a professor at the University of South Dakota. He is also president of OmegaQuant, a company that analyzes the content of foods. “There seemed to be a benefit, and they were safe, so there was just no downside. Everything looked good, so why not do it?”

The AHA continues to endorse the use of fish oil, suggesting that people with heart disease, particularly those who don’t eat much fish, “may want to talk to their doctor about supplements.”

In 2003, some of the researchers who conducted the early and influential DART study published the results of a follow-up. Of 3,000 Welsh men with angina — a chest pain caused by coronary heart disease — some were advised to eat oily fish or take fish oil supplements. This time, the fish group patients were more likely to die, and the researchers said it was particularly worse for those taking the fish oil pills.

“The excess risk [of cardiac death] was largely located among the subgroup given fish oil capsules,” they reported.

Hmm, that's not good.

Anyway, another reason to be interested in the sale of fish oil is Menhaden, the local filter feeding fish that forms an important link in the food chain (big stripers like nothing better than big Menhaden). Fish oil is one of the major products produced from the fish, which is netted in mass quantities in the Virginia portion of the Bay (it is caught in the Maryland portion of the Bay primarily as crab bait, and chum). One of the important economic driving forces behind the Menhaden fishery is the extraction of oil for fish oil capsules. Without that premium market, the menhaden industry would be less economically viable.

So maybe you should just have the occasional meal of a nice fatty fish, like salmon, blues or croaker, and skip the fish pills. And maybe you can help save the bay.