If you ever happen to be in Chicago, don't touch the tuna at the sushi bars (and where else would you read such vital travel information?). It's so full of mercury that one serving is as much as a woman or child should be exposed to in a month.
And one serving in seven has such high mercury content that a woman or child should never eat it.
The problem came to light when the Illinois Environmental Protection Agency tested tuna samples from 20 sushi bars in Chicago. They found that 14 - or 70 per cent - had unacceptably high levels of mercury.
Illinois is thought to be particularly bad for mercury levels because of the coal-burning power plants in the state, and the improper disposal of waste that contains mercury.
Women who are pregnant, thinking of becoming pregnant or who are breastfeeding are especially warned off the tuna. And it's reckoned that 100,000 Illinois women have blood-mercury levels high enough to cause development problems in their unborn babies.
Mercury is a potent neuro-toxin that can affect the fetus and the development of young children and their ability to learn. Higher levels also increase the risk of heart attack in adults.
So guess what they put in our teeth cavities? I tell you, eat a tuna sandwich after having a tooth filled and people will think you've been nobbled by a Russian secret agent.
(Source: Townsend Letter for Doctors and Patients, 2006; 281: 23-4).