Effects of repeatedly heated cooking oil consumption in mice: a study on health implications

Background: Cooking oils are a major part of human diets, but repeated use of heated oils can have detrimental effects on consumer health. This study aims to investigate the impact of different heating grades of vegetable oils on the hemato-biochemical parameters and vital organs like the heart, liver, kidney, and intestine in mice. Methods: Thirty mice were randomly assigned to different treatment groups, including a control group (diet only), unheated cooking oil (UHCO) group, single heated cooking oil (SHCO) group, three times repeatedly heated cooking oil (3RHCO) group, and repeatedly heated cooking oil (ReHCO) group. Blood and organ samples were collected on day 31 to investigate hemato-biochemical parameters and histo-morphological alterations in response to the oil treatments. Results: The oil-treated groups showed significant (P<0.05) decreases in the total erythrocyte, leukocyte, and hemoglobin levels. Meanwhile, serum levels of total cholesterol, triglyceride, high-density lipoprotein, glucose, and creatinine increased significantly (P<0.05), while low-density lipoprotein and protein levels dropped markedly in the treatment groups. Severe histo-morphological alterations were also found in the liver (hepatocytic degeneration with hydropic change in the 3RHCO and ReHCO groups), kidney (glomerular atrophy with increased glomerular space, tubular degeneration, and lymphocytic infiltration in the SHCO, 3RHCO, and ReHCO groups), and colon (lymphocytic infiltration in the mucosal layer of ReHCO group). Conclusions: These findings suggest that the consumption of heated oils can have severe adverse effects on consumers' health, leading to alterations in blood chemistry and damage to vital organs.