I have a new intern! Lora wrote up this q&a as a result of a question we received from a client. A great question and I’m thrilled to have Lora helping out on the Cancer Dietitian team!
Q: I have heard that olive oil is not as great as everyone says, if heated it turns to trans fat. True?
I will start by saying it is not true that olive oil is turned to trans fat when cooked at high
temperatures.
No doubt, you have heard that some fats are good for you
while others are bad. This is because
there are different types of fatty acids that have different chemical
structures. Think of the difference between olive oil, which is liquid
when left out on the counter, and lard or butter, which remain solid when not
refrigerated.
- The “good” fats, mono- and polyunsaturated fatty
acids, are found in plant products and are liquid at room temperature. - The “bad” fat, saturated fats, are found in
animal products and are solid at room temperature. - See Julie’s article about fats here: Dietary Fat Recommendations: Have The Experts Been Lying?
What are
Trans Fats?
Trans fats are actually vegetable oils that have been
processed and their chemical structure changed in order to make vegetable oils
more solid at room temperature. This is
a processing technique that food manufacturers use to extend the shelf life of
some products, such as baked goods.
In addition to extending the shelf life, it is CHEAPER to
manufacture solid fat, than to purchase solid fats like butter. However,
although it increases the shelf life of the product, trans fats has been shown
to be harmful to the body, and result in
an increased risk of heart disease.
Trans fats can be found naturally in small amounts in some
dairy and meats. However, these are not
the harmful trans fatty acids you typically hear about.
Using Olive
Oil for Cooking
Given that the production of trans fats requires a special
hydrogenation process that does not occur naturally through cooking, it is
impossible for olive oil to turn into trans fats while cooking, even at the
highest of temperatures.
What is true though is that olive oil has a lower smoke point than other vegetable oils, meaning
that it will start to degrade at lower temperatures. This isn’t necessarily harmful, but it can
produce an unpleasant taste. For this
reason, olive oil is not the best oil to use when cooking at high temperatures.
Is olive
oil a healthy oil?
With a recent interest in the health benefits of the
Mediterranean diet, olive oil is often promoted as a “healthier” vegetable oil,
which isn’t necessarily the case. Vegetable
oils differ in their content of saturated and unsaturated fatty acids.
- Olive oil is comprised of approximately 15-20% saturated fatty acids, while canola oil is only about 5% saturated fatty acids.
- Other
recently popular vegetable oils, like coconut and palm oils, can
contain almost 50% saturated fatty acids, and are more solid at room
temperature like meat fat and butter. - Vegetable oils, including olive oil, are a healthier choice than animal fats.
Want to know about Canola oil? Check out Julie’s article here: Quick Q&A: What is Canola Oil?
Should you
cook with olive oil?
If you’re cooking at a lower temperature, less than about 350˚F,
then olive oil should be fine. Olive
oils also work well in recipes that do not require heat, such as in salad
dressings and marinades. When choosing
which vegetable oil to cook with, consider not only the nutritional value of
the oil, but which oil is best for the type of cooking you are doing.
– Lora
References:
- http://www.eatingwell.com/healthy_cooking/healthy_cooking_101_basics_and_techniques/why_you_shouldn_t_always_cook_with_olive_oil?page=4
- Nutrition for Health, Fitness & Sport, 10thEd
