A Greasy Situation: Your Guide to Cooking Oils

Grocery shopping has become a difficult task over the years as the number of products has increased exponentially. How do you choose the best products when there are so many different variations of the same item? Bread has a whole side of an aisle all to itself! Head over to the oil aisle and you’ll find the variety just as great. Often, too many choices can leave you confused. What is the difference between virgin and non-virgin oils? What does “cold-pressed” even mean? Which oils should be used for dressings and which can withstand heat? How do different oils affect one’s health? The answers to these questions will help you select the oil that best fits your needs.

First, how exactly are oils produced? And how do those production methods affect the quality of the oil and our health? According to the Harvard T.H. Chan School of Public Health, canola, soybean, corn, and palm oil, which also happen to be the most consumed oils in the United States, are produced using a process called “refined, bleached, and deodorized,” or RBD for short. First the seeds are crushed to expose the oil, then subjected to a low-boiling solvent, usually hexane, to extract the oil. Finally, the extracted oil is deodorized by heating it to over 200 degrees Celsius (392 degrees Fahrenheit) and vacuumed to get rid of any overpowering taste or odor, making the oil more palatable to consumers. All vegetable oils in the United States are subjected to this final deodorization step except for cold-pressed oils. Due to the nature of some of the solvents used to expose the oil, like hexane (which is classified as a neurotoxin for humans), some believe the RBD process maybe unsafe; however, there are no studies to support this. Also exposing oils to high temperatures during the deodorizing process could result in the healthy fatty acid compounds and other nutrients in some oils to breakdown and lose their value according to Mayo Clinic. But not all oils are processed using the RBD method.

Healthy fats can be broken into two categories:

1. Monounsaturated fats -fats that help reduce LDL, or “bad cholesterol.” Olive oil is an example of a monounsaturated fat.
2. Polyunsaturated fats -fats that reduce LDL and increase HDL (“good cholesterol”), possessing wonderful health benefits. Walnuts are rich in polyunsaturated fats.

Not-so-healthy fats are also in two categories:

1. Saturated fats -fats that increase LDL, elevating ones risk of heart disease. Butter and cheese are rich in saturated fats.
2. Trans fats -these fats, according to Mayo Clinic, are a double whammy, increasing LDL cholesterol and decreasing HDL cholesterol. Trans fats, also known as partially hydrogenated oils, are found in highly processed foods because they increase the shelf life of products since they are less likely to spoil than other types of fats.

Cold-pressed is the second method used for oil production. Brandi Ducharme, owner of The Olive Oil Experience in Rockford, Illinois, which sells only the best quality olive oil according to Rockford locals, took it upon herself to extensively study oil production methods so she could identify the best quality oils for her store. According to Ducharme, pressed oil is produced when the fruits are harvested and then pressed with a machine to crack and squeeze the oil out of the seeds and fruits. In some cases, special attention is paid to ensure the machinery and the oil never exceed 80 degrees Fahrenheit. Keeping temperatures low during production is important to preserve the nutrients and antioxidants in the oil as well as the makeup of the healthy fat components according to Ducharme and the Harvard T.H. Chan School of Public Health.

Ducharme explains when choosing pressed oils one should also pay attention to the notations extra virgin, virgin, and light. Extra virgin means the oil is made with the first press of the fruit. This grade of oil contains the most nutrients and flavor. Virgin oil is with the second and third squeeze, containing less nutrients and less flavor. Finally, light oil is the last squeeze of the fruits and may even be subjected to the RBD process.

So, how are different oils produced? How do they affect one’s health? And what are their best uses?

Avocado oil: Boasting superior nutritional value, avocado oil is extracted using the cold-pressed expeller method, so it is best to choose the extra-virgin avocado oil to ensure maximum nutrient content, based on the recommendations of the American Oil Chemist Society. The Society also reports avocado oil has a high smoke point, making it an oil good for deep frying and cooking at high temperatures. Avocado oil is rich in monounsaturated fats, which reduce LDL cholesterol, and has polyunsaturated fatty acids, which reduce LDL and increase HDL cholesterol. Enjoy avocado oil for cooking but also as part of a dressing.

Canola oil: From the experts at the United States Canola Association, canola oil comes from the canola plant, which is frequently confused with the rapeseed plant. In the 1960s, the Canadian government used traditional breeding techniques and created canola by getting rid of the undesirable traits of the rapeseed plant. Canola oil is produced using the RBD method. Scientists at the Harvard T.H. Chan School of Public Health promote canola oil as an oil rich in monounsaturated fats. As a result, consuming canola oil helps reduce LDL cholesterol. Since canola oil is heated to high temperatures during production, using canola for cooking is acceptable.

Coconut oil: Coconut oil has been in the lime-light for the past couple of years due to its newly perceived health benefits. People have claimed it to be beneficial for everything from moisturizing to teeth whitening to preventing Alzheimer’s disease. But what does current research say? According to a 2015 paper from the University of Ajman, virgin, or unrefined, cold-pressed coconut oil is the highest quality and in its most natural state, compared to refined coconut oil which is processed via the RBD method and is tasteless and odorless. Both types of coconut oil are rich in a unique type of fat called medium chain triglycerides. Experts are still unsure how coconut oil affects one’s blood cholesterol levels, but a literature review published in the Nutrition Review Journal in 2016 states coconut oil raises LDL cholesterol more than plant oils but less than butter. Therefore, switching out butter for coconut oil may help reduce bad cholesterol levels.

Domestic Engineer Tawheeda Saqa from Rockford, Illinois, says she uses unrefined coconut oil instead of butter in most of her baking. Saqa loves using it when making brownies because the combination of the coconut fragrance, chocolate flavor, and smoothness of the brownies is mouth-watering.

Flaxseed oil: Flaxseeds come from the flax plant. According to the Canadian International Grains Institute, Flax Canadian 2015, flaxseed oil is harvested using the RBD method. It is rich in the essential fatty acid alpha-linolenic acid, which the body converts to omega-3 and omega-6 fatty acids, and plays a prominent role in reducing LDL and increasing HDL cholesterol according to the University of Maryland Medical Center and the Canadian Flaxseed Council. Flaxseed oil does not handle high temperatures very well; experts at Mayo Clinic recommend saving it for salad dressing.

Grape seed oil: Extracted from grape seeds using the RBD method, grape seed oil, much like flaxseed oil, is rich in linoleic acid, which the body converts to omega-3 and omega-6 polyunsaturated fatty acids and antioxidants according to the University of Maryland Medical Center. Although these fats should have a positive effect on blood cholesterol levels—lowering LDL and increasing HDL cholesterol—so far the research is insufficient to come to that conclusion, but, according to the University of Maryland, it looks like preliminary studies are showing positive results. According to Katherine Zeratshy, R.D., L.D. from Mayo Clinic, grape seed oil is good for cooking at lower temperatures like sautéing but not good for deep frying as it will start to release smoke and the nutrients in the oils will begin to breakdown.

Olive oil: Extra virgin olive oil is one of the most well know oils around the world. It is held in high regard for its health benefits and has been harvested in the Mediterranean basin for centuries. Extra virgin olive oil is produced using the cold-pressed method and when purchasing the oil it is important make sure the packing clearly states “cold-pressed” to ensure the best quality oil with the most nutrients and healthy fats, says Ducharme. Extra virgin olive oil is rich in monounsaturated fatty acids, which reduce high LDL cholesterol levels. Olive oil tolerates mild cooking temperatures, so sautéing is okay but deep frying is not a good idea. Best used “raw,” drizzle olive oil on hummus or dress a salad with it for added flavor and nutrients.

Sesame seed oil: Rich in antioxidants, sesame seed oil has been extracted for thousands of years using the cold-press method, where the seeds and the oil never exceed 120 degrees Fahrenheit. In more recent years, chemicals have been used to get better yields of the oil, but these chemically harvested oils are used more in cosmetic products according to the Bayero Journal of Pure and Applied Sciences from Africa. Sesame seed oil is rich in vitamin E and many other antioxidants. The Tropical Agriculture Research Lab conducted a study in 2013 comparing sesame seed oil to vitamin E oil and found sesame seed oil to be superior to the vitamin E oil in all accounts and classified sesame seed oil as “an edible oil with high potential for antioxidant activity.” Sesame seed oil can be incorporated into cooking in numerous ways. Mayo Clinic categorized it as healthy to cook with at high temperatures and for deep frying. It can also dress up salads and sautéed stir fries as well.

Sunflower oil: Sunflower oil is another heart-healthy oil due to its monounsaturated and polyunsaturated fatty acids. This oil also has a high smoke point, making it a good oil for cooking and deep frying. Sunflower oil is extracted using the cold-press method with the least amount of intervention possible to ensure pure, nutrient-rich oil according to the Food and Agriculture Organization.

MUFA: Monounsaturated fatty acids, PUFA: Polyunsaturated fatty acids, Sat: Saturated fatty acids, MCS: Medium chain saturated fatty acids

There are numerous varieties of oil, each with their own unique flavor, nutrients, and culinary abilities. Try experimenting with different types, experiencing their tastes, aromas, and textures. Focus on the sensation of the oils and how they flavor the food. Using different oils exposes you to different nutrients and antioxidants. Who knows? You may even find a new favorite.

Sarene Alsharif, MPH, is a nutritionist and public health professional accredited by the Academy of Nutrition and Dietetics. Her passion is health promotion and disease prevention through nutrition and wellness education.