Beer, when used as a marinade, can help reduce the formation of potentially harmful cancer-causing substances in grilled meats, scientists have found.

Previous studies have shown an association between consumption of grilled meats and a high incidence of colorectal cancer.

Polycyclic aromatic hydrocarbons (PAHs) are substances that can form when meats are cooked at very high temperatures, like on a backyard grill.

High levels of PAHs, which are also in cigarette smoke and car exhaust, are associated with cancers in laboratory animals, although it is uncertain if that is true for people.

Beer, wine or tea marinades can reduce the levels of some potential carcinogens in cooked meat, but little was known about how different beer marinades affect PAH levels, until now.

The researchers, from the University of Vigo in Spain and University of Porto in Portugal, grilled samples of pork marinated for four hours in Pilsner beer, non-alcoholic Pilsner beer or a black beer ale, to well-done on a charcoal grill.

Black beer had the strongest effect, reducing the levels of eight major PAHs by more than half compared with unmarinated pork.

"Thus, the intake of beer marinated meat can be a suitable mitigation strategy," researchers said.

The study appears in American Chemical Society's Journal of Agricultural and Food Chemistry.