If you’ve followed the “he said, she said” controversies about seafood and health in recent years, you’d be forgiven for not knowing how to make heads or tails of all the advice. But if you’re about to become a mother, your baby’s health may depend on making sense of the static.

Government scientists and nutritionists say Americans should be eating more than twice our 5-ounce weekly average of fish. But at the same time, environmental groups encourage panic about trace levels of mercury that accompany the undeniable health benefits.

Harvard researchers say those benefits — including heart health, stroke prevention and healthy fetal development — overwhelmingly (yes, overwhelmingly) outweigh the hypothetical risks. In fact, you won’t find a documented U.S. case of mercury poisoning related to eating commercially available fish in all the published medical literature. Zero. Zilch. Nada.

But unfortunately, fish stories are just like every other media phenomenon: Bad news makes for better headlines. So mercury fears, however misguided, tend to out-shout the reasons our mothers taught us that fish was “brain food.”

And in America’s poorest households, children are being left with the short end of the fish stick.

ACNielsen, the same company that monitors Americans’ television-viewing habits, also tracks our retail food purchases. And according to its data, more than 4.4 million U.S. households earning $30,000 or less completely stopped buying canned tuna between 2000 and 2006. (These findings are detailed in a new report titled “Tuna Meltdown,” available at www.MercuryFacts.org.)

Why does a drop in low-income families’ tuna consumption matter? In addition to being the constant whipping boy for green-group mercury campaigns, canned tuna is often the only source of omega-3 fatty acids—the “good fat” that boosts heart health and brain function — that fits in a low-income family’s food budget. If you’re looking for omega-3s, there’s no way to get a better bang for your buck.

Here’s the scary part: More than 250,000 children were born into those 4.4 million underprivileged families. Their mothers weren’t buying canned tuna, and ACNielsen reports that they weren’t stocking up on salmon or sea bass instead.

Without omega-3s in utero, these children are 29 percent more likely to have abnormally low IQs. So says a landmark study, funded by our own government and published last year in the prestigious British medical journal The Lancet.

The irony would be delicious if the consequences weren’t so tragic. In their zeal to protect Americans from mercury, environmentalists have apparently made millions of the poorest moms-to-be too scared to protect their babies by eating fish. Activists and some government bureaucrats have caused the very harm they intended to prevent.

Seafood warnings are hurting, not helping, America’s most vulnerable kids. Sad? Yes. Shameful? Absolutely.

There’s no evidence that unborn children are suffering any ill effects from the parts-per-billion mercury levels in tuna, either. Dr. Ashley Roman of the New York University Medical Center told Reuters last summer that “there has been no case of fetal mercury toxicity due to fish consumption reported in the United States.” Again, a big zero.

The entire mercury panic may, in fact, be the only public-health “epidemic” in history without a body count.

There have always been traces of mercury in fish. Princeton University researchers tell us that mercury in the ocean is mostly due to undersea volcanoes and mercury-bearing rocks. As fish consume other ocean life, their mercury levels naturally compound over time. But not to levels that are typically harmful to any people.

Our government recognizes this without admitting it. The Environmental Protection Agency’s own data show that a 130-pound woman would have to eat a pound of swordfish, two pounds of Chilean sea bass, or almost three pounds of yellowfin tuna — every week for her entire life — before her blood-mercury levels could tip the scales into “unhealthy” territory.

The only actual harm, it turns out, is generated by the environmental campaigners spearheading the fish panic. They do it for a variety of reasons, including the bizarre belief that fish deserve the “right” to not be eaten.

But in the face of real harm caused to real children whose economic disadvantages have already put them behind life’s eight-ball, it may be time to put such agendas aside.

Fish is a health food, not a poison. It’s time green groups and our government leaders thought of the children and gave that message serious priority. Pregnant women need to hear it. Their children’s future will depend on it.