A single glass of even the most contaminated wine isn't poisonous. But drinking just one glass of wine a day -- a common habit in Europe and the Americas might be hazardous, feel the biomolecular scientists Declan P. Naughton, PhD, and Andrea Petroczi of Kingston University, London.
Naughton calculated "target hazard quotients" (THQs) for wines from 15 countries in Europe, South America, and the Middle East. The measure was designed by the U.S. Environmental Protection Agency to determine safe levels of frequent, long- term exposure to various chemicals.
A THQ over 1 indicates a health risk. Typical wines, Naughton found, have a THQ ranging from 50 to 200 per glass. Some wines had THQs up to 300. By comparison, THQs that have raised concerns about heavy-metal contamination of seafood typically range between 1 and 5.
"I was surprised at this finding, and would be very interested if regulatory authorities and food-safety people will look at this," Naughton tells WebMD. "The wine industry should look at ways to remove these metals from wine, or to find out where the metals come from and prevent this from happening."
All the oxidating metal ions found pose potential problems. But the manganese contamination particularly worries behavioral neurotoxicologist Bernard Weiss, PhD, professor of environmental medicine at the University of Rochester, N.Y. Weiss was not involved in the study.
"Any time you see numbers like they have in this study, you begin to scratch your head and wonder about the effects over a long period of ingestion: Not one glass of wine last Tuesday, but a glass a day over a lifetime," he says.
Manganese accumulation in the brain, Weiss notes, has been linked to Parkinson's disease.
Safe Metal Levels
Wines from three of the 15 nations studied had safe levels of heavy metals: Italy, Brazil, and Argentina. Argentinean and Italian wines did not have significant maximum THQ values.
Hungary and Slovakia had maximum potential THQ values over 350. France, Austria, Spain, Germany, and Portugal had maximum potential THQ values over 100.
"If you buy a bottle of wine, the only thing it tells you on the label is the amount of alcohol. I like the idea of labeling wines with the amounts of heavy metals they contain," Naughton says. "Many wines don't have these metals. So let customers vote by choice whether they want the heavy metals."
It is not known where the heavy metals come from. Possible sources could be the soil of the vineyards in which the wine grapes are grown, the fungicides sprayed on the grapes, and possible contaminants in the yeasts used to ferment the wine.
Scientists did not directly measure heavy metals in the wines, but calculated THQs from data published in scientific journals. Since there was no data on heavy metals in U.S. wines, they did not include North American wines in their analysis.
Weiss says he'd like to see such data. He'd be interested to see whether national health databases can link health problems to daily wine consumption, and whether wine drinkers have higher concentrations of heavy metals in their bodies than teetotalers do. |