Rapeseed oil is an oil obtained from the rapeseed Brassica napus Linnaeus, belonging to the Brassicacea family. This plant is mainly cultivated in Europe and Asia and the seeds are used for the production of the oil and a high-protein animal feed. Traditional rapeseed oil is rich in erucic acid that has been found to cause toxicity in humans when consumed in large doses. This toxicity is not immediately apparent and takes around 10 years to manifest.
Effect of Rapeseed Oil on the Heart
The original variety of rapeseed has a high content of erucic acid, which can range between 20 to 55 per cent. Erucic acid is a long chain monounsaturated fatty acid. Animal experiments have shown that this compound can cause lesions on the heart, leading to significant heart damage. This oil is therefore considered unsafe for consumption by humans.
Effects of Rapeseed Oil on Metabolism
Metabolism of food takes place through various biochemical changes in the body. This process involves the action of many enzymes that act in coordination to digest and promote absorption of food. Rapeseed oil shows a tendency to reduce the efficiency of this process.
Rapeseed Oil and Cancer
Raw rapeseed has high levels of omega-3 oils, which have a beneficial effect on the heart. During the processing of rapeseed oil, however, these oils get oxidised and give a rancid odour, which is removed by a deodorisation process. This process causes the formation of trans fats. These compounds are known to be carcinogenic; that is, they have cancer-causing potential.
Modified Rapeseed Oil
Modified varieties of the rapeseed plant were developed to give oil with a low content of erucic acid. Such oil goes by the name of low erucic acid rapeseed (LEAR). LEAR oils contain low concentrations of erucic acid and are therefore considered safe to consume. One such oil is canola, produced from a genetically modified variety of rapeseed. Canola contains only around 2 per cent of erucic acid and is thought safe for human consumption. Canola is used for cooking and in normal amounts, does not cause side effects. However, consuming large amounts of canola without food can lead to a stomach upset and diarrhoea.