Chances are you take a fish oil supplement. Along with vitamin D, it's generally considered a supplement with solid evidence of health benefits. Ever gotten a bottle where one of the capsules had leaked? I have. Rrrrrripe. Unless you have the stomach of a turkey vulture, you won't be able to swallow them... and for good reason. Rancid fish oil is bad for you. Omega-3 fatty acids are delicate and oxidize quickly. Ingesting rancid fish oil unleashes a nasty dose of free radicals on your system for which your body has to use up its precious antioxidants to neutralize.
Here's the thing. Fish oil can go bad at any point from the factory, to sitting on a store shelf, to being in your house waiting for you to take them. Because the oil is inside a capsule, you can't really know. However, you can minimize your risk by taking the following precautions.
That should keep you in the clear. Another option is krill oil, which I'll be discussing in a future post.