MNN - Mother Nature Network

Dear Vanessa,

 

I want to get the omega fatty acids from fish but avoid the mercury, so I've started taking fish-oil capsules. But now I've heard that those have mercury in them, too. Do they?

 

— Wary in Washington

 

Dear Wary,

 

Your concerns about mercury in fish oil are widely shared.

 

Check out this post for a rundown on the risks and benefits of eating fish. You'll find that mercury is just one of the major contaminants regularly found in seafood; exposure to polychlorinated biphenyls (PCBs), dioxin, DDT and other organochlorine pesticides are just as alarming.

 

Do these toxins find their way into fish-oil supplements? If they're in the source, they can be in the supplement. But supplements can be "cleaned," and properly purified supplements have lower levels of mercury and PCBs. Purification of fish oils by molecular distillation seems to be the method of choice. Also look for the oil's source: If it comes from a species known to be low in contaminants (e.g., sardines, anchovies, tilapia) that was fished sustainably from oceans known to be relatively clean, then you're probably safe. (For more on which species are the most toxic, check out MNN's guide to mercury in fish here.)

 

So, how to find a good supplement? Nothing is ever simple ...

 

The FDA says omega-3 supplements are "generally regarded as safe," but supplements aren't subject to review and approval requirements like prescription medicines are. Some fish-oil manufacturers are "USP-verified," which indicates compliance with standards set by the US Pharmacopeia — a seal of approval that's widely recognized. Many manufacturers also seek IFOS (International Fish Oil Standards) certification, but there are some claims that IFOS is a marketing tool for manufacturers, and that its standards are too low. Note that while some companies make the claim, there is no "pharmaceutical grade" standard in the United States for fish-oil supplements.

 

The Environmental Defense Fund surveyed 75 supplement companies to determine whether they purified their fish oil, what methods they use if so, and what standards they comply with. I'd start there.

 

Some other things to look for:

 

 

Looks like you've got some good options for safe supplements. But I just can't help myself ... We get into trouble when we start to think supplements can replace real or whole foods. We have come to think too often of food as a store of various independent benefits and dangers — fats, vitamins, fiber, carbohydrates — from which we should pick and choose. But there is a complexity to whole foods, a synergy between elements, that cannot be mimicked by the elements alone: Nutrients function differently as part of a whole than in isolated form. That's not to say supplements can't be beneficial. They certainly can — perhaps especially fish oils. Whether in the form of vitamin tablets or fortified drinks and snacks, however, supplements are expensive. It's a lot of money for something that may not be doing you much good.

 

Well, that's my daily homily out of the way.

 

Once again, what started as a simple question ...

 

Stay green,

 

Vanessa

 

 * Molecular distillation is a process that spins the oils around rapidly to separate the toxic metals from the fish. 

 

(Photo: jmschemel/Flickr)

 

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