Toxic Aldehydes Detected in Reheated Oil (2 of 2) (video) FECYT - Spanish Foundation for Science and Technology Share Print E-Mail Loading video... Caption Researchers from the University of the Basque Country have been the first to discover the presence of certain aldehydes in food, which are believed to be related to some neurodegenerative diseases and some types of cancer. At frying temperature, sunflower oil produces more harmful compounds than olive oil. Credit SINC Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.