Rethinking Fish Oil: 4 Facts About Your Favorite Supplement

Is fish oil really beneficial, safe and environmentally friendly?

Depending upon whom you ask, fish oil is both wonder supplement and health menace. It protects against heart disease, but it can contain mercury. It’s linked to lower risk of breast cancer and diabetes, but it can be contaminated with PCBs. Fish oil is fraught with contradiction, and we haven’t even had dessert yet.

As the number one, most-purchased health supplement even over multivitamins, fish oil flies off shelves around the world for that greasy substance procured from the flesh of cold-water fish like sardines, anchovies and herring. Hailed as the best natural source of omega-3 fatty acids DHA and EPA, these vital substances are necessary supplements our bodies can’t synthesize on their own.

These long-chain essential fatty acids work wonders on our health. We’ve known for years that fish oil promotes heart health, but recent studies seem to crown it king of all health tonics – it may lower the risk of developing breast cancer or diabetes, protect against blindness and even aid in the treatment of mental disorders. Beyond that, it’s considered to be possibly effective for high blood pressure, rheumatoid arthritis, menstrual pain, kidney problems and a host of other health issues.

But for every study touting the miraculous effects of fish oil, there’s another warning of hidden dangers in the form of toxic contaminants. The presence of mercury in seafood is a well-known concern, and a lawsuit filed in 2010 against eight popular fish oil supplement manufacturers alleges unsafe levels of polychlorinated biphenyls (PCBs), which are carcinogenic.

Then there’s the sustainability issue: we can’t ignore the fact that fish populations are plummeting around the world due to overfishing and environmental contamination. Are we contributing to this problem when we buy fish oil?

Google all of these issues and it’s easy to see that straight answers aren’t easy to come by.  But among all the studies, recommendations, glowing reviews and dire warnings, a few things seem clear:

Worldwide medical bodies agree that benefits outweigh the risks.
They key is moderation; most people don’t need more than 500 milligrams per day. Warnings about mercury content in fish are aimed at high-risk groups like pregnant women, young children and the elderly. Plus, mercury is more often found in large, predatory fish – not the small fish used to produce fish oil.

Some brands of fish oil are healthier and more sustainable than others. The Environmental Defense Fund has a handy color-coded guide to fish oil supplements indicating which brands conform to the strictest standards for safe levels of contaminants. Look for supplements made from 100% wild fish, which contain fewer contaminants than those made with farmed fish. You can check the sustainability of particular fisheries at and the WWF.

Eating whole fish may be more effective than taking fish oil supplements.
Most dietitians recommend getting vitamins, minerals and essential fatty acids from nutritious whole foods – including fish. One study comparing absorption of omega-3’s in fish oil versus whole fish over six weeks found that levels of DHA were nine times higher in those who ate the fish. The Environmental Defense Fund has a chart listing fish that are both high in omega-3 fatty acids, low in environmental contaminants and easy on the environment.

Plant-based sources of omega-3’s are available, but may be less effective. Flax seed, walnuts, spinach and other ‘green’ sources of omega-3’s contain short-chain fatty acids, which must undergo a relatively inefficient conversion process in our bodies. Marine-based omega-3’s are more potent, but some people – especially vegetarians – may prefer the veggie source nonetheless.

Image: vintagedept

Stephanie Rogers

Stephanie Rogers currently resides in North Carolina where she covers a variety of green topics, from sustainability to food.