Effect of raw and repeatedly fried mustard oil intake on metabolic and organ histological changes in Wistar rat

Fried dietary oils often cause adverse health effects due to altered chemical and nutritional properties. In the present study with mustard oil, the effect of repeated frying (180°C for 10 min, three times) on chemical characteristics and oral intake of raw and fried mustard oil (5 g/kg for 5 weeks) in Wistar rats were investigated. Repeated frying caused oxidation reactions and free fatty acid content in mustard oil. This fried oil feeding to rats increased serum LDL cholesterol and triglycerides and decreased HDL leading to nonalcoholic fatty liver disease accounted by significant increment of liver enzymes (ALT, AST, ALP) compared with raw oil‐fed group. Higher level of serum CK‐MB and creatinine in fried oil‐fed rats indicate disrupted kidney function. Histological findings of the respective organs ascertained metabolic abnormalities due to fried oil intake. Thus, the study suggests avoidance of using repeatedly fried oils in food products for better consumer health. Practical applications Vegetable oil is a common ingredient of food products. Mustard oil is used in many countries both as raw and fried forms for various food preparations. When it is being fried at elevated temperatures in the presence of air, both thermal and oxidative decomposition take place which alter the nutritional and functional bioactive properties of the oil. The findings of the current study revealed the repeatedly fried mustard oil‐induced detrimental effects on various organs of Wistar rats. Human beings consuming repeatedly fried mustard oil regularly might also face these acute problems. Thus in context to the public health issue, it is a message to avoid in taking repeated fried oils at household cooking or food industry to maintain better health. Repeated frying caused formation of free fatty acids in the mustard oil. Consumption of the repeatedly fried mustard oil caused altered lipid metabolism in Wistar rats. The elevated level of serum biomarkers denoting to cardiovascular disease, nonalcoholic fatty liver disease and glomerulosclerosis were also ascertained by histological findings of respective organs.