There are many oils and even more ways to apply them, consuming them as a dietary nutrient is important, and is key to health, well-being and nutritional balance. There are numerous considerations when selecting the best oil for you, taste, consistency at room temperature and something known as a 'smoke point', a term that refers to oil exposed to heat. Heat can play havoc with the chemical structure of oil, particularly very high temperatures such as those reached when frying. Some oils endure heat more favourably than others, whereas some oxidise at relatively low temperatures. Oils whose fatty acids oxidise at lower temperatures have what is known as a ‘low smoking point’, and are considered less suitable for frying. An oil that oxidises creates a number of harmful free radicals which are highly unstable molecules with just one electron in their outer shell. The volatility of free radicals result in damage to the body’s cells including the inner cells of blood vessels which can increase the risk of heart disease and diabetes, as well as damage to major organs, increasing risk of certain Cancers. Granted, the odd use of olive oil when frying isn’t going to develop Cancer on its own, but the persistent practice may increase the risk. So in order to minimise any unnecessary risks, take a look at what oils you should and shouldn’t use when cooking.
Fats : Some are better than others, right?
Right. There are a plethora of oils out there, some more exotic than others, and some that your parents and your parent’s parents will have used for decades, even centuries! Butter and lard are some of the oldest known fats, with butter making a surge in popularity since the recent quashing of old schools of thought that had butter as public enemy number one. It was saturated fat that was considered the main problem with butter, but a meta- analysis by Siri- Tarino et al. (2009), and several other studies besides, all seem to suggest that not enough evidence exists to assert that saturated fat is the main risk of cardiovascular disease. Despite these findings, the public have still be drilled to believe that saturated fat, and any foods that consume it, are bad for our health, and the fact is that they’re not, in fact it seems that no natural fats are particularly bad for our health if consumed in….you got it, MODERATION (it’s a cliché for good reason, because it’s right). The only fat is known to be bad for our health are trans- fats, those nasty hydrogenated types of fat that are found in fast food, bakery products such as pastries, margarines (yup, that supposed ‘healthy’ butter alternative), and biscuits. Artificial trans- fats are oils that are pumped with hydrogen in order to make them more solid, making it an ideal agent for processed foods. Although trans- fats can be found in natural sources such as meat and dairy, they are present in relatively small amounts, and usually come with less total fat, sugar and salt when compared to many processed foods.
A unanimous leader in the fat world is olive oil, this is a monounsaturated fat that comes with many health benefits such as reducing inflammation and offering lubricative properties to joints and connective tissue. Olive oil is a staple in what many consider to be the healthiest diet out there, the ‘Mediterranean diet’, and is most commonly consumed in its raw form or cooked at low heat with some pasta dishes (for example). Another key player in the fat world is coconut, this is partly because researchers dispelled the ‘saturated fat being bad for health’ myth and have since found other key health properties in this valuable fat source.
The ‘best’ oil doesn’t always mean it’s the ‘right’ oil
An oil is only as good as its application.... take olive oil as an example:
Despite olive oil being the favoured oil for health, it does heavily depend on its application. Olive oil comes in different forms including refined olive oil, virgin olive oil, and extra- virgin olive oil, with the latter being of a higher quality. Extra- virgin olive oil tastes better with a fruitier undertone, as well as containing no more than 0.8% free acidity meaning it has lower free oleic acid and indicates a lower rate of degradation. When it comes to putting olive oil on your food raw, nothing beats it, but cooking with it at very high temperatures i.e. frying, increases the likelihood of it entering its smoking point and altering its chemical structure. This could mean the oil loses its antioxidant properties and becoming a trans- fat. The better the quality of olive oil, the higher the smoke point (usually between 365-400 degrees Fahrenheit), so it pays to opt for an extra- virgin olive oil. As well as this, olive oil is more likely to reach its smoke point sooner if it is repeatedly heated and reheated, so once you use an oil to fry, get rid of it and don’t re-use it. To get the most out of your olive oil, use it on salads, on pasta and veg, or as an addition to an oven roast of some sort.
Rapeseed has had a bad rap in the past, this is mainly because there are some dubious, lesser quality forms of the oil out there, and because of the high levels of erucic (approx. 54% of the oil is erucic acid). Erucic acid was linked to some cardiac problems in animals, but most rapeseed oils are now free from this high volume of erucic acid (no more than 5%) meaning it is now considered safe. Not only is it considered safe, but it is deemed to be one of the best oils for roasting veg and potatoes, this is because of its high smoking point making it suitable for frying also. Rapeseed is also high in vitamin E, (50% more than olive oil), 10 times more omega- 3, and contains just 6% saturated, that’s approximately 50% less than olive oil.
The humble coconut is synonymous with desert islands and nourishment, for millennia the coconut has given humans food and drink in one, nutrient packed package. One of its main and most popular features is the oil that is extracted from the coconuts flesh. This flesh is approx. 50% lauric acid, one of the main components that makes the coconut so healthy. Lauric acid is a healthier variety of saturated fatty acids and gives coconut oil the medium chain triglyceride structure (MCT). Coconut oil is solid at room temperature meaning it isn’t pourable until melted, but fortunately melting is fine because it has such a high smoking point meaning it is ideal for frying with. Such are the health properties of coconut oil that it is now added to coffee, stirred into porridge, and regularly used to fry eggs and chips (for example).
This is by no means an exhaustive review of oils, there are many varieties of oil meaning it is far beyond the scope of this article to address them all, but hopefully this review on the main varieties will help us as consumers make an informed decision when choosing what oil to use, and more importantly…when. Irrespective of how ‘healthy’ an oil is deemed to be, there is one pertinent point to remember… Oils are fat, and fat is calorific! In fact, fat packs 9kcal per gram making it the most calorie dense macronutrient of all. If oils are consumed to excess then expect weight gain, and if weight gain is allowed to escalate, expect comorbidities such as heart disease, diabetes and cancer. So, oils are great, they have their uses, but it is on us to ensure those uses play to the strengths of that oil. If you can get this right and consume them in moderation, then there is every chance you will have a healthy and delicious relationship with oils.
Mail Online, (2015). So which cooking oil is the healthiest choice for frying? Retrieved 2nd April, 2015, from http://www.dailymail.co.uk/health/article-3018666/So-cooking-oil-healthiest-choice-frying.html#ixzz3WAOqgTBO
Brassica napus was originally described and published in Species Plantarum 2:666. 1753. GRIN (24 February 2010). "Brassica napus information from NPGS/GRIN". Taxonomy for Plants. National Germplasm Resources Laboratory, Beltsville, Maryland: USDA, ARS, National Genetic Resources Program. Retrieved 25 November 2013.
Livestrong.com, (2011). Does overheating olive oil turn it to trans fat? Retrieved 2nd April, 2015, from http://www.livestrong.com/article/446570-does-overheating-olive-oil-turn-it-to-trans-fat/
"United States Department of Agriculture: "Grading Manual for Olive Oil and Olive-Pomace Oil"". Retrieved June 25, 2013. From http://en.wikipedia.org/wiki/Olive_oil
Siri- Tarino, P, W., Sun, Q., Hu, F, B. and Krauss, R, M. (2009). Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. The American Journal of Clinical Nutrition. doi: 10.3945/ajcn.2009.27725