Here’s what’s fishy about fish oil. (Gillian Brockell/The Washington Post)

By Peter Whoriskey

July 8, 2015

For anyone wondering about whether to take a fish oil pill to improve your health, the Web site of the National Institutes of Health has some advice.

Yes. And no.

One page on the Web site endorses taking fish oil supplements, saying they are likely effective for heart disease, because they contain the “beneficial” fatty acids known as omega-3s.

But another page suggests that, in fact, the fish oil pills seem useless: “Omega-3s in supplement form have not been shown to protect against heart disease.

“I can see how you might think that there is some inconsistency,” Paul R. Thomas, a scientific consultant in NIH’s Office of Dietary Supplements wrote in response to questions about the NIH pages.

fish oil

Few issues better reflect the American confusion over diet.

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.

The “accrual of high-level evidence,” according to a review of studies published last year in an American Medical Association journal, shows “that the supplements lack efficacy across a range of health outcomes.”

While the persistent popularity of fish oil may reflect the human weakness for anything touted as a life-extending elixir, it also reflects that, even among scientists, diet notions can persist even when stronger evidence emerges contradicting them. Scientists, sometimes, are reluctant to let go of ideas.

“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.

For example, his research showed that various claims regarding vitamin E, estrogen and beta-carotene continued to find an audience among scientists — as reflected in scientific papers — even when initial claims about them appear to have been trounced.

“What we have found is that the original papers continue to be cited well after they have been refuted,” he said. “These claims do not easily die away.”

Sorting through warnings

American consumers have long had to sort through confusing contradictions over what food is healthful to eat. And the trouble lies partly in the realm of science, where researchers sometimes have developed diet advice that, despite weakness in the supporting evidence, has been urged on the public.

This year, for example, a federal advisory panel recommended withdrawing the government’s long-standing warning about consuming foods rich in cholesterol, decades after scientists began to argue that the warning was wrongheaded.

Likewise, the long-lived admonition that Americans are using too much salt is facing a strong challenge from research published in prominent medical journals.

The dispute over fish oil and its fatty acids known as omega-3s, meanwhile, is part of a long and confusing debate about the role of fats in the American diet. As far back as 1977, the U.S. Dietary Goals, a forerunner of the federal government’s influential U.S. Dietary Guidelines, called for Americans to eat more carbohydrates and eat less fat. That position is now widely regarded as misguided.

A closer look at the fish oil recommendation shows how health authorities first recommended fish oil despite mixed evidence, then let the recommendation stand even as studies suggesting their worthlessness mounted.

The result can be confusion.

The American Heart Association, for example, recommends that some people with heart disease “may want to talk to their doctor about [omega-3] supplements.” But when the association was asked for an expert to explain the recommendation, that expert, former AHA president Robert Eckel, said that the recommendation needs to be revised.

“It would be a good time for that to be updated,” Eckel said. “Almost all studies of fish oil supplements show no benefit. I really feel this remains unproven.”

An AHA spokesman added: “AHA guideline committees are always reviewing guidelines and assessing whether updates are needed. AHA cannot discuss any guidelines or statements that are currently in the works.”

As for the confusing advice on the NIH Web site, Thomas said the page that endorses fish oil was provided to the NIH by a third party that assesses diet advice.

“Their conclusion that fish oil omega-3s are likely effective for heart disease is generous,” he said. “Whether fish oil can help healthy people prevent or reduce their risks of cardiovascular disease when taken over months and years is still an open scientific question.”

A fish oil story

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.

That finding didn’t stop the growth in sales of fish oil pills, however, even though the pages of the academic journals were filling with evidence that fish oil has no benefits.

Andrew Grey and Mark Bolland, researchers at the University of Auckland in New Zealand, for example, last year reviewed fish oil research published in major journals between 2005 and 2012 based on randomized clinical trials. Twenty-two of the 24 studies showed no benefit, according to their work published in JAMA Internal Medicine.

It is possible that fish oil has health benefits that scientific experiments are not sensitive enough to detect.

Most trials have focused on the effects of fish oil on people who have had a history of heart trouble. The trouble with those studies is that such patients are typically taking an array of heart medicines, such as statins, blood thinners and beta blockers. It is possible, scientists say, that the effects of the fish oil can’t be detected among the effects of the other medicines.

An ongoing trial of 26,000 people, however, will focus on the effects of fish oil on a broader set of patients — including those who don’t already have heart disease or use multiple heart medicines.

JoAnn E. Manson, principal investigator of the trial and chief of preventive medicine at the Harvard-affiliated Brigham and Women’s Hospital in Boston, said that it is biologically plausible that omega-3s could protect against heart disease, though there’s not enough evidence to recommend fish oil supplements routinely.

“It’s amazing how popular the fish oil supplements have become without conclusive evidence of their efficacy,” she said.

In the absence of clear messages from health authorities, however, consumers are faced with a barrage of unproven promises.

“The omega-3s [EPA and DHA] in fish oil help support a healthy heart,” according to Nature Made, one company that sells the supplements.

“Their benefits go far beyond the heart,” says Nordic Naturals, which boasts of offering the “#1 selling fish oil in the U.S.”

And Dr. Tobias, another leading fish oil company, suggests that the pills help defend against a remarkable array of ailments. It says “supportive but not conclusive studies indicate benefits of Omega 3 essential fatty acids” for heart disease, dementia, ­Alzheimer’s, arthritis, symptoms of asthma, pneumonia, depression, suicide, wrinkles, acne and psoriasis.

“At the end of the day, omega-3s are healthy fats,” said Adam Ismail, executive director of the Global Organization for EPA and DHA Omega-3s, an industry group. “We believe they prevent heart disease.”



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Peter Whoriskey Peter Whoriskey is a staff writer for The Washington Post whose investigative work focuses on American business and the economy. Previously, he worked at the Miami Herald, where he contributed to the paper’s coverage of Hurricane Andrew, which was awarded a Pulitzer Prize for public service. Follow Reporting the facts for over 140 years.


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7/18/2015 2:44 AM EDT

More benefits emerging for one type of omega-3 fatty acid: DHA… 
A study of the metabolic effects of omega-3 fatty acids, especially DHA, concludes that these compounds may have an even wider range of biological impacts than previously considered, and suggests they could be of significant value in the prevention of fatty liver disease. 
The research, done by scientists at Oregon State University and several other institutions, was one of the first of its type to use “metabolomics,” an analysis of metabolites that reflect the many biological effects of omega-3 fatty acids on the liver. It also explored the challenges this organ faces from the “Western diet” that increasingly is linked to liver inflammation, fibrosis, cirrhosis and sometimes liver failure. 
Higher omega-3 levels equal less brain shrinkage with age… 
People with higher levels of the omega-3 fatty acids found in fish oil may also have larger brain volumes in old age equivalent to preserving one to two years of brain health, according to a study published in the January 22, 2014, online issue of Neurology®, the medical journal of the American Academy of Neurology. Shrinking brain volume is a sign of Alzheimer’s disease as well as normal aging. For the study, the levels of omega-3 fatty acids EPA+DHA in red blood cells were tested in 1,111 women who were part of the Women’s Health Initiative Memory Study. Eight years later, when the women were an average age of 78, MRI scans were taken to measure their brain volume. Those with higher levels of omega-3s had larger total brain volumes eight years later. Those with twice as high levels of fatty acids (7.5 vs. 3.4 percent) had a 0.7 percent larger brain volume.  



7/18/2015 3:32 AM EDT

Omega-3 supplements, antioxidants may help with preclinical Alzheimer’s disease… 
Here’s more evidence that fish oil supplementation and antioxidants might be beneficial for at least some people facing Alzheimer’s disease: A new report describes the findings of a very small study in which people with mild clinical impairment, such as those in the very early stages of the disease, saw clearance of the hallmark amyloid-beta protein and reduced inflammation in neurological tissues.  
Omega-3 fatty acids boost B vitamin brain benefit… 
Authors Fredrik Jernerén and colleagues hypothesize that “low total homocysteine concentrations, which are the consequence of B vitamin treatment, facilitate the protective effect of omega-3 fatty acids against brain atrophy.”  
Fish oil may improve immunity… 
New findings from a Michigan State University-led study suggest a possible role for fish oil in improving immunity among people with certain health conditions. 
The fatty acids contained in fish oil are thought to be effective at reducing inflammation. That’s good, says MSU researcher Jenifer Fenton, because inflammation contributes to rheumatoid arthritis, celiac disease and other autoimmune disorders in which the immune system attacks the body’s healthy cells. 
But inflammation is a sign of increased immune system activity – it’s why wounds get red and puffy as they heal – so it’s widely thought that if fish oil fights inflammation, it may also influence overall immune function. 

See More



7/13/2015 3:07 AM EDT

The only thing for sure we know about fish oil supplements is a whole bunch of “doctors” made a mint promoting them. And by the way, isn’t the “science settled on heart health?” How can something so crucial and endlessly studied still have uncertainties? I know how: heart heath doesn’t advance socialism, so the Left has no real need to “solve” that problem.


Neil Sorens

7/12/2015 4:59 PM EDT

The science is settled, deniers. Stop trying to do more science on supplements. And carbs are good and fat is bad. We have studies. Stop doing new ones funded, no doubt, by Big Fat. 
The government has spoken.



7/12/2015 1:59 PM EDT

The Mayo Clinic has been looking at this issue much longer than random WaPo reporters and has a list of which effects are well-proven and which are mostly debunked. Overall, it appears to have some real benefits.…




7/12/2015 1:48 PM EDT [Edited]

I remember the 2003 study, there was a self-selection problem with people who had heart issues more likely to take them. 
Unfortunately we don’t have a journalistic class capable of interpreting data. Science reporting is uniformly awful and overwhelmingly leftwing.



7/12/2015 10:18 AM EDT

Fish oil deniers. The science is settled.



Stephanie Gray Winnard

7/11/2015 2:30 PM EDT

You can get all the omegas you need from plant sources, and let the fish be. Stop killing our beautiful marine life and decimating our oceans for this snake oil! A whole foods, plant based diet not only prevents heart disease but in many cases can reverse it. Fish feel pain, and soon there will be no life left in our oceans if humans don’t stop the gluttonous destruction of our oceans.



7/11/2015 8:27 AM EDT

I don’t know about fish oil but all the overfishing is making it impossible for me to catch a fish off of Virgina piers. Give the oceans a break and realize that fish are a finite resource which needs to be properly managed. Those sharks trying to eat people in Carolina are sending all of us a message, the predators are hungry for a reason.


Gabriel Andrew

7/10/2015 6:19 PM EDT [Edited]

Essential Fatty Acids are essential… 
“Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is a primary structural component of the human brain, cerebral cortex, skin, sperm, testicles and retina. It can be synthesized from alpha-linolenic acid or obtained directly from maternal milk or fish oil.”



Gabriel Andrew

7/10/2015 6:09 PM EDT

Great propaganda post brought to you by the pharmaceutical industries. See, the FDA approved prescription fish oil – Lovaza – and should not have done so if it was not proven to be effective. But it was proven so, therefore fish oil is effective. See the studies –… 
Try fish oil yourself and you will see that it works. It is costing the pharmaceutical companies billions.




7/10/2015 11:55 AM EDT

A very reasonable explanation for the failure to demonstrate clinical effectiveness of fish oil was articulated in an analysis published in the European Heart Journal in 2012 entitled “Fish oil and omega-3 fatty acids in cardiovascular disease: do they really work?” The authors argue that dramatic changes in the treatment and management of cardiovascular disease patients in the ten-year period since the clinical trials demonstrating the effectiveness of fish oil in patients surviving a first heart attack. The first drug capable of inhibiting endogenous cholesterol biosynthesis, atorvastatin (Lipitor), was approved in 1996 and first became available in 1997. Beginning in the late 1990s, therefore, the inclusion of a statin into standard cardiac disease practice significantly changed the risk of sudden death and the risk of a second heart attack faced by all heart disease patients. In the GISSI-P study published in 1999, for example, only 29% of the participants were on a statin. During this period, the absolute risk for fatal coronary arterial disease was 15.8/1000 person-years. In the recent Alpha Omega Trial, however, fully 85% of the participants were on a statin and the risk of fatal coronary arterial disease was 8.9/1000 person-years. During the 10–11 period between the two sets of studies, sudden death rates have fallen from 10.4/1000 to 3.7/1000 person years between the two studies, nearly one third of the original death rate. The increase in statin use, and the decrease in absolute risk of death for all cardiac patients appear to explain the difficulty in obtaining statistical significance and the apparent loss of effectiveness of omega-3 fatty acids in secondary prevention. Survivors of a first heart attack, once receiving modern medical care, are no longer at very high increased risk of a second attack. Interesting.


Tim Buist

7/10/2015 10:21 AM EDT

The financial section of the Washington Post apparently has a better grip on this issue than the AHA. Unfortunately the scope of research cherry picked for this article is narrowed to cardiovascular disease. The anti-inflammatory effects combined with other lifestyle adjustments are where the real promise lies, with many studies to support.…




7/10/2015 4:04 AM EDT [Edited]

Do any of you know about the endocannabinoid system? It does a lot more than just get you high when you use cannabis. Learn a little about it, then read these abstracts- “Nutritional omega-3 deficiency abolishes endocannabinoid-mediated neuronal functions” and “The importance of the ratio of omega-6/omega-3 essential fatty acids. ” (both are at PubMed).




7/10/2015 2:48 AM EDT

I cannot swim and have been taking fish oil for many years in the hope of remedying this condition. The fish oil has proved to have no efficacy whatsoever and I have been forced to buy a boat in preparation for a rise in sea level but have recently found a study proving that boats do not provide any benefits to non-swimmers. We need more consistent science on these issues.




7/10/2015 1:37 AM EDT

They sell fish oils in ophthalmologist’s offices for dry eye syndrome.



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