Heavy metals have been linked to neurological problems such as Parkinson's disease and may also increase oxidative stress, which can lead to chronic inflammatory disease and cancer, the researchers noted.
"We used literature reports of concentrations of metals in wines originating from 16 countries to determine the Target Hazard Quotients (THQ) for these wines," said lead researcher Declan Naughton, a professor of biomolecular sciences at Kingston University in South West London. "Many of the wines gave very high THQ values, which is concerning."
Among wines from Portugal, Austria, France, Spain, Czech Republic, Hungary, Germany, Serbia, Argentina, Brazil, Italy, Jordan, Macedonia, Slovakia and Greece, only three countries had wines that posed no hazard from heavy metals. Based on the wines analysed, only those from Argentina, Brazil and Italy had THQ values that were below 1.0.
How the study was done
The report was published in the online edition of Chemistry Central Journal. For the study, Naughton and his colleague Andrea Petroczi used the THQ, a formula developed by the US Environmental Protection Agency to look for seven heavy metals in wines. These included vanadium, copper, manganese, nickel, zinc, chromium and lead.
Naughton and Petroczi found that most wines had THQ values much higher than 1.0. In fact, THQ values typically ranged from 50 to 200. Red and white wines from Hungary and Slovakia reached THQ levels of 300.
"For consumption of 250 mL (8.5 oz.) daily, these wines give very high THQ values and may present detrimental health concerns through a lifetime," Naughton said.
Because heavy metals can pose a health threat, Naughton and Petroczi recommend that levels of metal ions should appear on wine labels. "This would help inform customer choice," Naughton said. "In addition, where necessary, further steps should be introduced to remove key hazardous metal ions during wine production."
No wines from the United States were included in the study, so it is not possible to tell the heavy metal content of wines produced in this country. One critic of the study does not think U.S. wines contain dangerous levels of heavy metals.
More research still needed
"The US [Alcohol and Tobacco] Tax and Trade Bureau routinely performs market basket surveys in the U.S. to test wine and alcohol for a number of components, including heavy metals," explained Gladys Horiuchi, communications manager at the Wine Institute of California.
Joan R. Davenport, a professor of soil science in the Department of Crop and Soil Sciences at Washington State University, thinks a lot more study needs to be done to figure out how these heavy metals are ending up in wine.
"Knowing what I know about not only growing wine grapes, but the whole process of turning them into wine and looking at some of the countries where these wines came from, it makes me wonder what may happen in the processing," Davenport said.
A lot of the heavy metals found in the wines in the study, exist in only very small quantities in soil, Davenport said. "The likelihood of that being in the grapes isn't very likely," she said. The contamination could be coming from the metal barrels used in processing the wine, she added.
Davenport isn't worried that these metals are a health problem. "I'm not going to drink any less wine," she said. "Enjoy what you enjoy in moderation. But if you like only Hungarian wine, you might be in more trouble than if you like Argentinean wine." – (HealthDay News, October 2008)
Read more: Life's good for mice on red wine