Well, they’re not quite the modern-day equivalent of snake-oil salesmen, but the parallels are irresistible. In the 19th century, snake oil was promoted as a cure for joint pain and other ills, and the figure of the snake-oil salesman was widely ridiculed. (Ironically, snake oil is still used as a treatment in China today, despite the lack of any evidence for its efficacy.)

Today we have a new figure: the fish oil salesman. This modern figure, though, is no joke: he is a polished, sophisticated figure with the full weight of the FDA behind him. Should we buy his product?

Last week, while watching a major sports event, I was treated to a new commercial for a product called Lovaza, which I learned “helps to lower very high triglycerides in adult patients.” It’s a beautiful commercial, with an actor in a lab coat (am I supposed to think he’s a scientist?), carrying a clipboard and walking through a lab surrounded by blue aquariums. (Apparently the lab is under water.) You can see the ad here.

Lovaza, made by GlaxoSmithKline, contains a high dose of omega-3 fatty acids, the “good fat” contained in oily fish such as salmon and tuna. In 2004, the FDA announced that it would allow the following health claim for omega-3 fatty acids:

“Supportive but not conclusive research shows that consumption of omega-3 fatty acids may reduce the risk of coronary heart disease.”

Not surprisingly, this announcement gave a big boost to dietary supplements made from fish oil. Omega-3's are the fifth best-selling supplement in the U.S., with sales of $600 million per year, according toa 2008 Wall St. Journal article.

What’s new about Lovaza? Mainly this: no other fish oil supplement (and there are many) has FDA approval, as the TV ad made clear. What FDA approval means is that the manufacturing process for Lovaza has been rigorously evaluated and the product is guaranteed (well, almost) to contain what it is supposed to contain, without contaminants. (As I wrote just last week, many supplements contain harmful contaminants.) This approval transforms Lovaza (like magic!) from a supplement into a pharmaceutical, and you can only get it (in the U.S.) with a prescription.

Why bother to go through the FDA process when you can sell the same supplement over the counter? Here’s the clever part: as an FDA-approved treatment, Lovaza is eligible for insurance coverage, which also means that GSK can charge an exorbitant amount of money for it. As cardiologist and blogger Dr. William Davis explained on his blog, this means that people in his area are paying $3360 per year to take fish oil pills, which they could buy at the local Costco for $150/year. It looks like getting FDA approval was a great deal for GSK, although not such a great deal for the consumer.

Of course, the makers of fish oil supplements have responded with countless articles claiming that their products are just as pure as Lovaza, and they very well might be. I’m not going to examine that question here.

But all of this kerfluffle about FDA approval ignores the most basic question: does it improve your health to take high doses of omega-3 fatty acids?

Er, no. Or maybe.

A recent (2010) meta-analysis by scientists from McGill University looked at 29 randomized controlled trials involving over 35,000 patients. They found that

“Omega-3 fatty acids were not associated with a statistically significant decreased mortality or with restenosis prevention.”

(Restenosis is narrowing of the arteries). They did find a small reduction in both conditions, but it was not significant. It appears that the FDA’s 2004 conclusion may be overly optimistic. So: either no benefit or a small benefit, but in any case fish oil doesn’t cause harm.

Remember, the Lovaza fish oil salesman only claims that it helps to treat people with extremely high triglyceride levels (over 500, where normal is less than 150). He never said it would reduce your risk of heart disease – in fact, he says in the ad that Lovaza has not been shown to prevent heart attacks or strokes. What this all means to me is that, if you have really high triglycerides, then it won’t hurt to take a fish oil supplement, but I can’t see any reason to spend 20 times as much for Lovaza.

Or you could make sure to eat plenty of oily fish like salmon. Sushi, anyone?