Does consumption of reused deep-fried oil lead to neurodegeneration?

Deep frying, which involves completely submerging food in hot oil, is a common method of food preparation around the world. Deep frying food not only adds calories; reusing the same oil for frying, a common practice removes many of the oil’s natural antioxidants and health benefits. Oil that is reused also can contain harmful components such as acrylamide, trans fat, peroxides and polar compounds.

“Deep-frying at high temperatures has been linked with several metabolic disorders, but there have been no long-term investigations on the influence of deep-fried oil consumption and its detrimental effects on health. To our knowledge we are the first to report long-term deep-fried oil supplementation increases neurodegeneration in the first-generation offspring,” said Kathiresan Shanmugam, an associate professor from Central University of Tamil Nadu in Thiruvarur who led the research team.

To explore the long-term effects of reused deep-fried frying oil, the researchers divided female rats into five groups that each received either standard chow alone or standard chow with 0.1 ml per day of unheated sesame oil, unheated sunflower oil, reheated sesame oil or reheated sunflower oil for 30 days. The reheated oils simulated reused frying oil.

Compared with the other groups, the rats that consumed reheated sesame or sunflower oil showed increased oxidative stress and inflammation in the liver. These rats also showed significant damage in the colon that brought on changes in endotoxins and lipopolysaccharides — toxins released from certain bacteria.

“As a result, liver lipid metabolism was significantly altered, and the transport of the important brain omega-3 fatty acid DHA was decreased. This, in turn, resulted in neurodegeneration, which was seen in the brain histology of the rats consuming the reheated oil as well as their offspring,” said Shanmugam.

Although more studies are needed, the researchers suggested that supplementation with omega-3 fatty acids and nutraceuticals such as curcumin and oryzanol might be helpful in reducing liver inflammation and neurodegeneration.

Reference: Sugasini Dhavamani, University of Illinois at Chicago, Jeyakumar Balakrishnan, Vinayaka Mission's Medical College and Hospital, Kathiresan Shanmugam, Central University of Tamilnadu; AMERICAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY; MEETING: Discover BMB