How Good For You is Fish Oil Really? | FRONTLINE
>>NARRATOR: The third most widely used supplement in America is fish oil. The Omega-3s contained in the oil are believed by many to be essential for good health.>>DHA Omega-3 in particular is extremely important.>>NARRATOR: It also helps prevent disease, according to the man who heads one of the largest fish oil trade associations.>>There’s certainly ample evidence that it helps things like reducing blood pressure, reducing your risk of coronary death.>>NARRATOR: But the science behind fish oil is a little more complicated than that.>>So these are two capsules. This is a FDA-approved product…>>NARRATOR: Dr. Preston Mason is a Harvard university researcher. Here, he’s comparing prescription-quality fish oil to the oil found in over-the-counter supplements.>>And give it a smell.>>It smells a little bit fishy, but not bad.>>Right. You’re gonna have always some smell.>>NARRATOR: One of the issues with fish oil is it’s delicate. It’s extracted as a byproduct from oily fish like anchovies. As the fish get crushed, the oil is exposed to oxygen, and it doesn’t take much oxygen to turn the oil rancid.>>This is a common supplement for fish oil. See what that smells like.>>Oh…>>What?>>That doesn’t smell good. That smells like it’s going bad.>>Yeah, right. It’s a very strong fishy smell.>>NARRATOR: If it was simply an odor issue, that would be one thing, but oxidized oil contains oxidized lipids, one of the building blocks of cells. We’ve long known that lipids, when oxidized, can be harmful.>>So an oxidized lipid triggers inflammatory responses within our body, particularly in our cells, and if we ingest oxidized lipid, we can trigger these inflammatory changes that can lead to things like cardiovascular disease.>>NARRATOR: Recently, Mason published his own study of fish oil supplements. The results were consistent with other studies, showing high levels of oxidation. One in New Zealand found 83% of fish oils tested failed to meet the industry’s own standard.>>It was shocking to see such a high proportion of products that had high oxidation levels. And so we went and actually bought 47 products from the New Zealand market and had them tested at multiple labs, and we did not see that same effect.>>Well, what was the percentage that you discovered that were not in compliance?>>It was around 20%.>>Would you agree that 20% is still problematic, from the consumer’s point of view?>>Well, if it’s truly 20%, then yeah, we would like to see those 20% improved.>>NARRATOR: But improving the quality won’t address the other issue with fish oil: the growing questions about whether it prevents disease. Two years ago, epidemiologist Dr. Andrew Grey compiled all the best studies on fish oil as reported in the world’s most prestigious scientific journals.>>I think for cardiovascular disease, one has to say there is no compelling evidence that taking fish oils protects against a first heart attack or a second heart attack. And so people who are advised to do that or are doing it are wasting their time and their money.>>NARRATOR: But the fish oil industry continues to insist there is a benefit, particularly for preventing heart attacks. We asked their spokesman to send us his best evidence, which included some of the same studies Grey had cited, and didn’t seem to support his case.>>This one says it doesn’t appear to reduce sudden cardiac death. The next one, “Insufficient evidence.” JAMA 2012: “Overall, Omega-3 supplementation was not associated with a lower-risk of all-cause mortality.” Another journal, “The evidence is not clear-cut, and any benefits are almost certainly not as great as previously believed.” So, that doesn’t seem to be suggesting there’s an overwhelming amount of evidence.>>Yeah, well, I think what you’re looking at are the abstracts.>>But the conclusions are the conclusions.>>But again, those papers are looking at very large areas of cardiovascular disease, and I think it’s hard to argue that Omega-3s aren’t important for how your heart functions.>>NARRATOR: Many researchers agree– if you get them from eating actual fish. The problem is, science still hasn’t proven it’s true for supplements.>>We would think that something that’s natural, that’s essential to normal cell function and body function, would have clinical benefits, it just has to be proven. But in the meantime, there’s certainly been a lot of promotion suggesting a benefit in everything from Alzheimer’s disease to cardiovascular disease. But we still need the strong clinical trial to validate those hypotheses.