Recent headlines announced that when it comes to regulating blood pressure, it’s better to eat fish rich in omega-3 fatty acids than to take fish oil supplements. But Dr. Barry Sears, an omega-3 pioneer and author of Omega Rx Zone: The Miracle of the New High-Dose Fish Oil, disagrees.
Researchers from the University of Pennsylvania published a study in the Proceedings of the National Academy of Sciences, in which they concluded that one of the omega-3s - docosahexaenoic acid (DHA) - is critical to maintaining proper blood pressure in blood vessels. It does this by rapidly activating channels that let ions such as sodium, calcium, and potassium in and out of cells.
However, they found that DHA ethyl ester, the form of DHA found in most fish oil pills, failed to activate the same channels. In fact, they said the DHA ethyl ester seemed to compete with the natural form of DHA from food and block it from binding sites on the ion channel.
The researchers concluded that these channels have receptors for long-chain omega-3 fatty acids, and that the free form DHA -- unlike DHA tied to an ethyl ester -- activates the channels and lowers blood pressure. They believe that their findings underscore the importance of obtaining omega-3 fatty acids from natural food sources such as oily fish rather than supplements.
But according to Dr. Sears, there are good reasons to minimize fish in your diet. “The problem with eating fish instead of taking fish oil capsules is that all fish are contaminated with toxins like PCBs,” he says. “The more fish you consume, the more PCBs you ingest. On the other hand, highly purified fish oils (unfortunately not those in health food stores) are incredibly low in PCBs as they are removed in the refining process. Not only are these omega-3 fatty acids more concentrated, but they are safer for long-term use.”
And the difference between free form DHA and DHA ethyl esters shouldn’t be a concern. Dr. Sears points out that the ethyl ester is simply a carrier for DHA in supplements just as a triglyceride would carry the DHA in the fish itself. In humans, unlike in cell culture studies, DHA must be attached to an ethyl ester or a triglyceride for it to be absorbed by the body. In fact, the vast majority of human clinical trials of omega-3s have used ethyl esters. Furthermore, if DHA were in its free form, it would be very unstable and susceptible to oxidation.
Dr. Sears has developed his own fish oil formulation called OmegaRx which is available online. It’s a highly refined omega-3 concentrate that is rich in both eicosapentaenoic acid (EPA) and DHA and very low in PCBs.
For more information on the health benefits of fish oil supplements read Dr. Sears’s book: Omega Rx Zone: The Miracle of the New High-Dose Fish Oil.