Many health-minded individuals understand that eating fried or overcooked foods is unhealthy due to the chemical transition of normally stable fats to trans-fats that have been shown to dramatically increase heart attack risk. Researchers from the University of the Basque in Spain publishing in the journal Food Chemistry are the first to discover compounds released from common cooking oils that significantly increase the risk of neurologic degenerative diseases and a variety of different cancers.
Breakdown chemical structures known as aldehydes are formed in cooked vegetable oils such as sunflower oil when heated to normal frying temperatures, and are also released into the air where they can be inhaled. Alternate food preparation methods such as roasting, steaming and broiling are safe methods of cooking foods to avoid the dangerous release of aldehydes and afford a shield against cancer forming particles and neurodegenerative decline.
Many Common Vegetable Oils Produce Dangerous Aldehydes When Heated
Prior studies have identified the health degrading nature of aldehydes, where their presence in organisms is linked to different types of cancer and neurodegenerative diseases such as Alzheimer's and Parkinson's. Researchers also know that these compounds remain in vegetable oils after they have been used to fry foods and wanted to determine how they interact with proteins, hormones and enzymes in the body to impede its correct functioning.
The study team heated three types of oil (olive, sunflower and flaxseeds) in an industrial deep fryer at 190 degrees Celsius for a period of forty hours (twenty hours was used for the flaxseed oil). This length of time was used to approximate oils used commercially at a restaurant where fryers remain heated for extended periods of time. The oils were then analyzed using gas chromatography/mass spectrometry techniques.
Extra Virgin Olive Oil is a Healthier Oil for Cooking
Researchers found that the sunflower and flaxseed oils degraded significantly and are the ones that create the most toxic aldehydes in the least amount of frying time. These oils are high in polyunsaturated fats (linoleic and linolenic) and breakdown quickly to form the health-demoting aldehyde compounds that permeate the air and penetrate into the food. Olive oil, known to be high in monounsaturated fat, generates aldehydes to a lesser degree and after cooking much longer.
The research team concluded “The fact that significant concentrations of these toxic compounds were found in some oils … is a cause of concern for human health.” Although the scientists did not use coconut oil in their tests, studies have shown that the medium-chain fatty acid does not rapidly convert to deadly trans fats when heated, and may be less likely to produce aldehydes when compared to other vegetable oils. While fried foods are not part of a healthy eating plan, it is important to avoid cooking with low flash-point oils that produce aldehydes and increase the risk of neurologic disorders and cancer.