A recent Cochrane Review published July 18 entitled Omega-3 Intake for Cardiovascular Disease basically concluded that increasing EPA and DHA (the two omega-3s found in fish) have “little or no effect on all-cause deaths and cardiovascular events”.
As you can imagine, this led to all kinds of hand-wringing headlines in the media (“Fish oil supplements do nothing to prevent heart attacks!” said Britain’s Independent) and no small amount of confusion on the part of consumers. Could we have been misled about the value of omega-3?
What we’ve been misled about is the value of these kinds of studies.\
The studies that produce shocking headlines like these are almost always observational studies, not clinical ones. That’s a huge limitation and it frequently leads to some really weird conclusions (for some amusing examples, keep reading). In observational studies, researchers observe—they don’t intervene. They collect massive amounts of data about people’s habits—what they’re already eating, what pills they’re already taking, how much alcohol they’re drinking on a weekly basis—and then, years later, look at their health outcomes. The idea is to connect the dots and uncover relationships between habits and health.
What they uncover sometimes isn’t real, and what they don’t uncover sometimes is. Let me explain.
Observational studies basically look for correlations between variables (like taking an omega-3 pill and living free of heart disease). The problem is, there are a lot of correlations where two things are found together—even in a statistically significant way—but one thing does not cause the other. (Think “rain” and “umbrellas”—found together all the time.) Furthermore, hundreds of correlations show up that essentially have no meaning whatsoever—they’re just interesting, quirky mathematical relationships. Nate Silver and his team of statistical whiz kids over at 528.com recently put together some actual, real-life, statistically confirmed correlations from observational data like the kind used in the “omegas don’t work” study. He published them under the title, “You Can’t Trust What You Read About Nutrition”. Here are a few examples:
It gets worse. You see that list of foods in the left hand column of the chart above? Well, all of these findings require that you get accurate information about how much of each food people in the study were eating. But that’s almost impossible to do. One of the dark secrets of nutrition research is that almost all of it uses a research tool called the Food Frequency Questionnaire which is stupendously awful. Here’s an example taken directly from the questionnaire:
As a busy person who can’t remember what he ate for breakfast yesterday, I shudder at the thought of building research conclusions about diet based on the answer to questions like the ones above.
And it’s exactly the same with supplements. You’d get questions like, “How many times in the last three months have you taken a fish oil ‘pill’?”
With questions like that, you’d have no what kind of omega-3 supplements were being taken. You wouldn’t know the dose, nor the quality. One person’s idea of a “fish oil pill” could be very different from another’s. And, on top of it all, we have no way of confirming the accuracy of the self-reports.
Interestingly, within months of the Cochrane report saying omega-3s do nothing, another large study was released showing that those with the highest levels of omega-3s in their blood actually live the longest. But unfortunately, that study—like the Cochrane report—was based on the same kind of basically useless data, even when they reach conclusions we agree with!
So the first reason you shouldn’t pay too much attention to studies like this is that they’re based on subjective recall of what people said they ate over the last few months and what “pills” they remembered taking over the last few months. Those data are—let’s be charitable—highly questionable.
But the second reason you shouldn’t worry too much about these studies is even more important, and it’s this.
Health is multi-factorial. No one habit—no one food you eat, no one “pill” you take, no one habit you cultivate—is, by itself, going to necessarily extend your life or protect you from every disease. The question should never be, “Did this supplement/food/diet/lifestyle habit protect me from heart disease?” Instead, the question should be, “Is this a habit that contributes to my overall health? Because in the end, all nutrients, phytochemicals, catechins, flavanols, vitamins, minerals, electrolytes, fatty acids work together in a synergistic way to create resistance to disease and a sense of vitality. No one ingredient alone can shoulder the burden.
That’s why so many of these studies are short-sighted and produce disappointing results. They’re asking the wrong question.
Good health results from a collection of habits. It’s a manner of living (which is why they call it lifestyle). No single nutrient—not even the spectacularly healthy omega-3—works by itself to change your life. If you’re eating 7 meals a day at a fast food restaurant and smoking Lucky Strikes, guess what—taking a fish oil “pill” isn’t going to protect you from heart disease.
But add that “pill” to a healthy diet, some sunshine, loving relationships and a healthy dose of exercise and all of a sudden you’re talking about a very different alchemy.
Thousands of studies—have documented the value of omega-3 in reducing inflammation, lowering triglycerides, lowering blood pressure. I don’t have to tell you that—you can go to PubMed and research it for yourself. Entire books—such as The Omega-3 Effect by Drs. Bill and Jim Sears, or Fish Oil: The Natural Anti-Inflammatory by Dr. Joseph Maroon—have documented the positive effects of omega-3s, complete with hundreds of scientific references. At some point we have to be smart consumers and start connecting the dots. As the great nutrition educator Robert Crayhon once said to me, “The entire New York City fire department doesn’t have a single double-blind study showing that water puts out fire, but they use it anyway because they’ve noticed that it works.”
Omega-3 may not be the one and only thing that keeps your heart healthy, but there’s plenty of reason to suspect that it makes a huge difference