I've gotten a couple of questions about fish oil lately that are very common. Thought I'd put them up in a blog post so that anyone who has these questions now has the answers now, and this post is available for future times when the questions are also asked.
1. Isn't fish oil full of mercury and therefore something to avoid?
Actually, fish oil is very heavily processed to removed the mercury. The technique used by most companies is called molecular distillation. Organizations like Consumer Reports routinely do random checks by pulling bottles off of a typical drugstore and testing the purity of the product they find. And, routinely, the findings are that the fish oil products tested are practically always pure. Of course, there's the occasional issue, but when it happens, the brand tends to be publicized and it takes care of the problem.
Brands I know and trust include: Kirkland Costco, Barlean's, Coromega, Omega 3 Brain Booster, Carlson's, and Nordic Naturals. That does not mean these are the only safe brands, these just happen to be the brands with which I am most familiar.
Look at it this way. The liability associated with not being careful to remove fish oil is so great that it would be a foolish business to not go through the trouble of distilling out the mercury.
Bottom line: Fish oil, especially if has been molecularly distilled, is relatively mercury free.
2. Is there an upper limit to fish oil?
The American Heart Association recommends no more than 4 grams of fish oil per day. I am guessing that the reason this upper limit exists is because fish oil can affect clotting time, cardiologists treat clotting disorders, and they want their demographic to be kept safe.
However…a 4 ounce serving of salmon has about 2 grams of omega-3's. I have never heard anyone, ever, suggest that we should restrict our intake of fish! So there is a bit of an inconsistency in how we disseminate this information.
Here is the advice I like to give. If you are concerned about getting too many omega-3's, and/or you have a history of blood clotting problems, it's best to be conservative. Start low and increase your dose as you gauge you are tolerating the omega-3's. If you are on any kind of medication such as coumadin, it's best to do this under the supervision of a physician, as your medication dose may need to be shifted as your body accumulates omega-3's. If you notice that you start to bruise more easily after starting fish oil supplementation, this may be an indication that your clotting time has changed and that you should drop back on your dose until you can meet with your physician.
My personal feeling is that in many cases, adequate omega-3 intake may help reduce the need for the medication, but the ultimate decision in each individual case must be one made between you and your physician.
I recently spoke to a gentleman whose lab has developed a test that can ascertain whether or not you have too many omega-3's in your diet. I am not completely versed on how the test works or what it measures, but if you are interested, you can get more information at www.metametrix.com.