The Consumer Council has rebuked an urban myth regarding canola oil in the September 2010 issue of CHOICE magazine. The myth continued to circulate on the Internet and via e-mail. Whilst there is no scientific evidence that canola oil is associated with mustard gas, bovine spongiform encephalophy (BSE, also known as Mad Cow Disease) or fatty degeneration in organs such as heart and kidneys, the concerns on its erucic acid and glucosinolates content are discussed below.
Misinformation about the safety of canola oil may arise from the erroneous belief that it is the same as rapeseed oil. In fact, the composition of canola oil is different from the traditional rapeseed oil (may contain very high levels of erucic acid up to 60% total fatty acids). Canola oil is made from the plant developed from natural cross breeding of the rapeseed plant and has very low levels of erucic acid (below 2% total fatty acids).
Safety and Public Health Significance
- Canola oil is low in saturated fat and has high proportion of unsaturated fat. It is a good source of both essential fatty acids, linoleic (18:2 n-6) and α-linolenic (18:3 n-3) acids ( ALA ), which cannot be produced in human. Essential fatty acids are important for normal fetal and infant growth and development, in particular, for brain development and visual acuity. In the body, ALA can be converted to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are associated with decreased risk of coronary heart disease.
- Erucic acid present in edible oil is a monounsaturated fatty acid (22:1 n-9). Tests on experimental animals found that excessive intake of erucic acid may damage their heart tissues, but this link has not yet been established in humans.
- Glucosinolates are toxins naturally present in Brassica plants such as rapeseed, cauliflower, cabbages, broccoli and Brussels sprouts. Glucosinolates in rapeseed (for producing rapeseed oil) and in the cross bred plant (for producing canola oil) can be reduced by heating during the oil processing. Glucosinolate-derived compounds may interfere with iodine uptake and thyroid function.
- Under the Harmful Substances in Food Regulations (Cap 132AF), the maximum concentrations of erucic acid in different oil/fat are listed below.
Description of food Maximum concentration Low erucic acid rapeseed oil 2 per centum by weight of its fatty acid content Any other oil or fat or any mixture of oil and fat 5 per centum by weight of its fatty acid content Any food to which oil or fat or a mixture of oil and fat has been added 5 per centum by weight of its fatty acid content of all the oils and fats in the food
Advice to the Public
- Canola oil is safe for consumption as part of a balanced diet. Reduce the use of oils during food preparation.
- When purchasing cooking oils, read the ingredient list and the nutrition label for an informed choice.
Advice to the Trade
- Observe Good Manufacturing Practice (GMP) in food processing and in edible oils production.
- Ensure the products comply with local regulations.
Risk Assessment Section
Centre for Food Safety