Scientists in Singapore have studied varieties of fried food and found potentially harmful particles released into the air when oil is heated to the temperature needed to cook chips or stir-fries, reported the online edition of Daily Mail.
All cooking oils produce these harmful particles but vegetable oil is the most dangerous.
Corn oil and olive oil also pose a risk. Deep-frying chips in particular produces large amounts of the cancer-causing chemicals polycyclic aromatic hydrocarbons (PAHs), the scientists say.
The chemicals, also found in tobacco smoke and exhaust fumes, are released when oil is heated to high temperatures.
University of Singapore researchers, who compared methods of Malaysian, Chinese and Indian cooking, said the deep-frying done by Malaysian chefs released more PAHs than the stir-frying in Chinese kitchens.
At the Indian food stall, much of the food was simmered or boiled, which cut down on the hydrocarbons.
The study said repeated exposure to these chemicals could increase the chance of lung, breast and bladder cancer.
The researchers estimate that someone regularly exposed to high levels of these chemicals would have a one in 100 chance of developing cancer.
"A comparison of the different cooking methods implies that deep-frying generates more PAHs than any other cooking method," University of Singapore researcher Dr Rajasekhar Balasubramanian said.
This could be due to the higher temperature maintained during cooking and the larger amount of oil used in deep-frying, he said.