In the last five months, we’ve had quite a few reasons to be disappointed with Today Show anchors, reporters and producers over errors theyve made about fish consumption. We first tangled with Today dietitian Joy Bauer over seafood and mercury beginning last March (click here, here and here). We got back in touch with her again in July when she suggested substituting one fish for another rather than just adding both to your back to school menu (click here).

Earlier this week, the show got it wrong again during a segment on “age proofing” your brain that featured host Lester Holt and his guest, Courtney Smith, editor of Prevention. While the segment started off on the right foot by discussing some of the latest research about how eating fish can help you stay sharp mentally as you age, it all went wrong when Holt asked Smith about mercury in tuna. In response, Smith said that individuals should limit their consumption of tuna to 6 ounces per week.

This is a classic example of misinterpreting the FDA guidance on fish consumption for pregnant women, women who are nursing, want to become pregnant and young children and applying it to the rest of the population.

For starters that advice says that group show feel free to have 12 ounces of light tuna a week and notes that: “[W]hen choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.” Once again, these restrictions only apply to that limited group and by no means apply to older folks who might want to increase the amount of fish they’re eating in order to keep mentally sharp as they age.

While its frustrating to see NBC, Prevention and many others continue to repeat this mistake, its far more worrisome if you consider the potential negative effect on public health. Misinformation like this has a tendency to encourage people to remove seafood from their diet altogether. Researchers from Harvard have already concluded that 84,000 Americans die every year because they don’t get enough of the Omega-3 fatty acids found in seafood like tuna. So, while NBC and Prevention might be patting themselves on the back for promoting caution they really need to be taking responsibility for making a public health issue worse than it needs to be by not doing their homework.