Impact of Edible Oil Processing on Human Health: A Review of Current Evidence and Future Research Gaps

Abstract

The rapid increase in edible oil consumption, largely driven by changing lifestyles and dietary patterns, has raised growing concerns regarding the potential health risks and safety implications associated with repeatedly heated frying oils. Two primary concerns arise from oil intake, either through high-fat diets or the consumption of fried foods. Evidence suggests that, in many cases, excessive intake of high-fat diets is directly associated with metabolic disorders such as fatty liver disease and insulin resistance. In addition, frequent consumption of deep-fried foods, particularly from street food vendors, exposes consumers to the potential hazards of oils that are subjected to repeated heating cycles. There is also considerable uncertainty among consumers regarding the appropriate choice of oil for deep frying. In domestic cooking practices, oils rich in unsaturated fatty acids, such as rice bran oil or soybean oil, are commonly used due to their perceived health benefits. However, when these oils are exposed to high temperatures and moisture during frying, they undergo significant chemical transformations, including the formation of free fatty acids. Furthermore, the oxidation-prone unsaturated double bonds present in these oils are readily degraded, leading to the generation of a range of secondary oxidised products, which may contribute to adverse health outcomes. A better nutritional approach in terms of quality is necessary specially for oil processing as it is the most vulnerable product in terms of undesired chemical changes. So, in future a proper monitoring system may be incorporated in the processing sectors along with new process design, and manufacturing of oil and oil-based food can be a boon to our society.