Repeated heating of vegetable oils/fat, results in oxidation of PUFA.
ICMR has warned that repeated usage of heated oil can increase the chance of acquiring cancer.
The Indian Council of Medical Research (ICMR) recently released 17 new dietary guidelines for Indians of all ages to help them make healthier food choices and live a good life. The guidelines seek to provide suggestions to assist Indians in making informed choices to preserve good health and combat malnutrition in all its forms. Saving and reusing cooking oil has long been a cost-effective method being used in many Indian households. In many homes, the used oil is stored for days before being reused. ICMR has warned that repeated usage of heated oil can increase the chance of acquiring cancer.
In their new guideline, the council mentioned, “The practice of ‘reusing’ vegetable oils for cooking, (which have been repeatedly heated during food preparations) is very common, both at homes and in commercial establishments. Repeated heating of vegetable oils/fat, results in oxidation of PUFA, leading to the generation of compounds which are harmful/toxic and may increase the risk of cardiovascular diseases and cancer.”
The council further suggested that at the household level, vegetable oil that has been used for frying should be filtered and utilised for other curry preparations. However, it warned that using the same oil for frying should be avoided. Furthermore, such used oils should be consumed in a day or two. Storing used oils for an extended period is not recommended because their deterioration rate is rapid.
Meanwhile, in its latest guideline, ICMR also dealt with the question of whether processing oil affects its quality. It stated that all extracted vegetable oils should be used in moderation because the extraction process may contain unwanted chemicals. Crude vegetable oils are likely to include various unwanted compounds; so, the crude oil is treated to a series of refining processes to eliminate these undesirable compounds, resulting in vegetable oils that are safe for human consumption. The council also explained that refining removes odours and increases the shelf life of vegetable oils. During the refining process, minor components such as antioxidants, and so on are eliminated without changing the fatty acid content. The refining process also adds various additives, including preservatives, which are not good and must be consumed in moderation.