How mercury can wreck little brains

Fish are the best source of essential omega-3 fatty acids around. Unfortunately, many fish are also high in something else -- something you don't want at all.

Mercury in fish and seafood is becoming such a huge problem that there are certain types of fish -- like swordfish and king mackerel -- that shouldn't even be on the menu at all, especially for pregnant women.

It's a double-edged sword(fish), and new research of mercury in fish shows just how fine the line is between benefit and risk: Children born to moms who get plenty of omega-3s have a lower risk of attention-deficit hyperactivity disorder... while kids born to moms exposed to mercury have a higher risk of the condition.

In the study, women used food diaries to track their seafood consumption during pregnancy. Then, researchers took hair samples to measure their levels of mercury exposure from the mercury in fish.

Moms with higher levels of mercury produced kids 40 percent more likely to show mild ADHD-like behavior and 70 percent more likely to battle full-blown impulsive and/or hyperactive behavior -- especially among boys (who have a much higher risk of ADHD in the first place).

By higher levels of mercury, we're not talking much -- just 1 microgram per gram, according to the study, or what many in the mainstream would consider to be both normal and safe.

Clearly, it shouldn't be considered normal or safe.

On the other hand, the study also found that women who consume two servings of fish per week or more give birth to kids that are 60 percent less likely to suffer ADHD -- and that's almost certainly thanks to the omega-3 fatty acids in fish, which are critical to brain development.

So can more of one cancel out the other? Don't bet on it either way.

Expectant mothers -- and everyone else, for that matter -- should get their omega-3 fatty acids from fish we know to be safe, such as salmon, herring, sardines, and mackerel to lower their risk for mercury in fish.

King mackerel, shark, tuna, and swordfish, on the other hand, tend to be much higher in mercury and should be off limits.

Making matters worse, there is a huge problem with high-risk fish being deliberately mislabeled to make them more marketable.

If keeping up with it all is too much of a challenge, try a purified omega-3 supplement from a manufacturer you trust instead. And if you want to test the levels of metals in yourself or a child or grandchild, make an appointment to see a holistic doctor, like me, who can run those tests for you.