From the Archives of Pediatric and Adolescent Medicine, a new study concludes that the consumption of fish during pregnancy is good (60% decrease in symptoms of ADHD in their children), but that the consumption of fish known to have high concentrations of mercury is bad (60% increase in ADHD symptoms in children).

Andrew Seaman at Reuters gets the study’s author to summarize:

“The really important message is to eat fish. Just stay away from mercury containing fish, because these protective effects are pretty important,” said Sharon Sagiv, the study’s lead author from the Boston University School of Public Health in Massachusetts.

Sagiv said it’s best to stay away from “big fishes,” which typically contain the most mercury. Those are fishes like tuna and swordfish. Instead, she said, stick to fishes like haddock and salmon.

How, you may ask, does mercury get into the environment and into these big fishes?  Stony Brook University has the answer:

Atmospheric inputs of mercury have increased threefold in the past two centuries and anthropogenic or man-made sources now are estimated to make up two-thirds of the mercury in the atmosphere. [1],[2]

Read more:

Study abstract here.