How to choose the healthiest cooking oil
Posted by kathryn in Fats & oils
After missing a month due to the 31 Days to a Better Diet series, Q & A Thursday is back.
The first question is from Maja who asks which is the healthiest oil for frying and roasting?
Why do we use oil in cooking?
Oil has to be one of the most frequently used cooking ingredients. We use it in dressings and when marinating foods. However it’s also the foundation of several cooking techniques: sautéing, roasting and stir frying.
Cooking in oil is different from cooking in water, because it heats to a higher temperature. While water turns to gas at 100°C, oils remain liquid at temperatures above 200°C.
This temperature gives food a crisper texture and more intense flavour.
What makes an oil more or less healthy?
There are three factors which affect the health quota of an oil:
- The type of fat it contains
- How the oil reacts to heat
- How much of the oil you use
1. The type of fat
There are three distinct groups of fat found in oils: saturated, poly-unsaturated and mono-unsaturated fatty acids. While all three are present in both animal and plant foods, different oils tend to be dominated by one group.
While we need each of these fatty acids in our diet, most people eat too much of the saturated kind. Here in Australia, on average people eat twice the recommended daily intake. And a high saturated fat diet is a problem, because it’s associated with an increased risk of cardiovascular disease, cancer and diabetes.
In contrast mono- and poly-unsaturated fatty acids are associated with health benefits. These include reducing cardiovascular risk and cognitive decline in old age, and improving mental health.
2. How the oil reacts to heat
The amount of saturated, poly-unsaturated and mono-unsaturated fatty acids varies considerably between different oils. This affects the stability of the oil and how it responds to heat.
Heat can change the structure, composition and flavour of an oil. All oils have a smoking point, although the temperature at which this occurs varies. If you heat an oil beyond it’s smoking point it will burn and the flavour deteriorate. More concerning for your health though, heating an oil beyond its smoking point encourages the production of free radicals.
To prevent this it’s important to choose an oil which remains stable at a high enough temperature for the cooking method you’re using.
3. How much of the oil you use
Even the healthiest of oils can be over-consumed. Oils are basically 100 percent fat. Which makes them a concentrated energy source and therefore high in kilojoules. Too much of even the best oils can contribute to weight gain. Quantity counts.
How to use some of the most common oils
- Olive oil: high in mono-unsaturated fats and has a lowish smoking point of 190°C. Therefore suitable for cooking at lower temperatures. Use for sautéing foods, adding at the end of cooking to flavour a dish, roasting foods in the oven at a lower temperature.
- Canola oil: high in mono-unsaturated fatty acids and has lowest saturated fat content of all the common oils. Has a higher smoke point than olive oil (240°C). Therefore suitable for higher temperature cooking, without affecting flavour or increasing free radical damage. Blander flavour makes it a good multi-purpose oil. Use in baked goods and for stir frying where a medium – high temperature is required.
- Sesame, peanut and sunflower seed oils: high in poly-unsaturated fatty acids and have distinct amounts of mono-unsaturates. At 232°C they have a higher smoking point than olive oil and are in a similar range to canola oil. Excellent for stir-frying or frying.
- Macadamia oil: different fatty acid profile from the other nut and seed oils. 85 percent mono-unsaturates, 14 percent saturates and virtually no poly-unsaturates. Has a distinctive flavour and medium smoking point of 210°C. Excellent for stir fries and roasting.
Five tips for using the healthies oil in your diet
- There is no one perfect oil. As with other parts of your diet, variety is the key. Use olive oil some nights, but also include canola, sesame, macadamia and so on. It’s the best way to ensure you’re getting the fatty acids you need.
- Buy cold pressed. Cold pressed and extra virgin oils are the first pressings from the nut and seed, which are extracted without heat or chemical solvents. These are purer, better oils, with a fuller flavour.
- Don’t exceed the smoking point. If you exceed the smoking point, you’re damaging the oil and increasing free radicals, so use the right oil for the cooking job.
- Avoid using too much. Find ways to reduce the overall amount of oil you use. While a recipe may specify tablespoons and cupfuls, it’s usually possible to reduce this down.
- Replace saturated fatty acids. Rather than adding mono- and poly-unsaturated fatty acids to your diet, use them to replace some of the existing saturates you use. Add canola oil to baking and dip your bread in olive oil, rather than using butter.
What about trans fats?
I specifically haven’t mentioned trans fats in this post, as they’re not regularly found in the oils we use at home. If you want to know more about trans then see my previous posts on the subject:
If you want to know more about cooking oils, then I have an article coming up in Wellbeing magazine. It will be published in the November issue.
What oils do you most commonly cook with?
04 September, 2008
Comments
Olive oil for roasting vegetables and sautéing. I also use it to make a salad dressing.
Peanut and sesame oil for stir fries :)
I have never tried macadamia oil but now I want to!
I make asian dishes with EV Tea Oil aka Camellia Oil – it’s delicious and says lots of good things about itself on the neck tag!
Kathryn, thank you for this comprehensive explanation. I was doing it quite right then. :)
Zoe, Camellia oil sounds great! Being a great tea fan, I’m excited about anything linked to Camellia sinensis, so I’m dying to find this oil :)
I knew there was a scientific reason why I shouldn’t use Olive Oil for cooking Indian food. Apart from the fact that it’s completely inauthentic, that is.
To use oil sparingly, invest in a manual pump designed to spray oil onto foods or into your pan before sautéing. Most kitchen stores sell them for ten to twenty dollars. A less expensive option that I use regularly is a small rubber basting brush designed to lightly coat foods with oil or sauces.
Fiona, I love macadamia oil. It’s a bit more pricey, but lovely when you want a different slant/twist. And I’ve used in recipes which call for walnut oil etc, to great effect.
Thanks for your suggestion Kami. A much better idea than buying those aerosol cans with olive oil.
Generally I use ghee for cooking particularly Indian, and olive oil for others, mainly Italian and Greek dishes. I don’t deep fry so it is mainly for sauteing. I used to use peanut oil for chinese stirfrys, but don’t cook them very much any more.
For salads I use walnut, grapeseed, olive and sesame oil.
Coconut oil is a very controversial oil – differing opinions on whether it is good or bad for you.
For low heat/raw use I use olive oil/extra virgin olive oil.
For high heat cooking I use rice bran or grape seed oil.
For mayonnaise I use macadamia oil (I love walnut oil but can only find French stuff which I don’t feel good about buying…so I only buy it about once every 2 years when I am overcome with lust for walnut oil mayo)
Dani: I can understand why you would become overcome with lust for walnut oil mayonnaise – sounds wonderful.
Coconut oil is the best oil out there – see exert from www.macola.com
- And polyunsaturated fats, which include common vegetable oils such as corn, soy, safflower, sunflower and canola, are absolutely the worst oils to use in cooking. These omega-6 oils are highly susceptible to heat damage because of all the double bonds they have.
I strongly urge you to throw out those omega-6 vegetable oils in your cabinets. Why?
Reason #1: Most people believe that frying creates trans fats. That is not the major problem, in my opinion. Although some are created, they are relatively minor. There are FAR more toxic chemicals produced by frying omega-6 oils than trans fats.
Frying destroys the antioxidants in oils and as such oxidizes the oils. This causes cross-linking, cyclization, double-bond shifts, fragmentation and polymerization of oils that cause far more damage than trans fats.
Reason #2: They contribute to the overabundance of omega-6 fats in your diet, and the imbalance of the omega-6 to omega-3 ratio. As you know from my extensive writing on this subject, I believe that excessive consumption of omega-6 fats contributes to many health concerns.
There is only one oil that is stable enough to resist heat-induced damage, while it also helps you promote heart health, maintain normal cholesterol levels and even supports weight loss — coconut oil.
So, whenever you need an oil to cook with, use coconut oil instead of butter, olive oil, vegetable oil, margarine, or any other type of oil called for in recipes. Even though I don’t fully recommend frying foods, if you must fry, by all means use coconut oil — it’s your smartest choice.
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