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Monounsaturated Fats

Also indexed as: Almond Oil, Avocado Oil, Canola Oil, Olive Oil, Peanut Oil

Suitable for a wide range of cooking temperatures, these fats—olive, canola, and peanut—are extremely popular.

Monounsaturated fats contain large amounts of monounsaturated fatty acids (MUFAs). MUFAs are so-named because, due to the presence of one double bond in the carbon chain, the fatty acid is not “saturated” with hydrogen. Monounsaturated fats are typically liquid at room temperature, but solidify when refrigerated.

Varieties

Monounsaturated fats include the following:

Buying and storing tips

Cooking oils can become rancid when exposed to heat, light, and oxygen. As a result, oil processing that uses these methods affects the nutritional content, storage life, and quality of oils. Choosing a high quality cooking oil can be a challenge unless one understands the terms that food manufacturers use to describe the methods by which cooking oils are processed. When purchasing cooking oil, it is important to review the label, and note the method of extraction, and whether the oil is refined or unrefined. Whenever possible, choose expeller-pressed, unrefined oils (see definitions below). Select oils in light-resistant plastic containers or dark brown or green glass containers.

Extraction Methods

Mechanical (expeller) extraction

During mechanical extraction, an expeller press crushes the seeds, nuts, or vegetables to extract the oil. This pressing is done under intense pressure, and raises the temperature of the oil to 185 to 200°F (85 to 93.3°C). Typically, nuts and seeds are heated up to 250°F (120°C) before being placed in the expeller; heating makes the pressing more efficient. Some manufacturers produce “cold-pressed” oils—a term typically used to describe oil that was extracted without using additional external heat. This term is also used when cold water is run through the expeller, keeping the temperature of the oil from rising. However, there is no legal or binding definition of “cold-pressed,” so oils may be so labeled even when temperatures were quite high during pressing.

Solvent extraction

Solvent extraction is a more efficient and complete method of oil extraction, and is therefore the preferred method of large cooking oil manufacturers. During solvent extraction, nuts and seeds are cracked to expose the oil, and then combined with a chemical solution containing a solvent (typically hexane). The solvent pulls the oil from the nut or seed. The oil-solvent mixture is then heated to about 300°F (150°C) to evaporate out the solvent.

Refining Methods

Unrefined oils

Once the oil is extracted (either through mechanical or solvent extraction), manufacturers may simply filter the oil to remove some impurities and sell it as unrefined. Unrefined oil retains its full natural flavor, aroma, and color, and many naturally occurring nutrients.

Refined oils

To extend the shelf life of the extracted oil, some manufacturers refine oils. Refining can include as many as 40 different steps, including bleaching, deodorizing, and degumming. Refined oils are clear, odorless, and less flavorful than unrefined oils, and are more suitable for high-temperature cooking.

When purchasing olive oil, choose oil that is labeled “extra-virgin” or “virgin.” Virgin olive oils are produced from the first pressing of the olives, and are unrefined. As a result, these oils are more flavorful and more healthful.

Store canola, olive, and peanut oils in the refrigerator or in another cool, dark place. When refrigerated, olive oil tends to develop hard, white flakes. These flakes do not alter the flavor or quality of the oil, and disappear once the oil reaches room temperature.

Availability

Canola, olive, and peanut oils are available in most grocery stores. However, to purchase expeller pressed, unrefined, and organic cooking oils, it may be necessary to go to a natural food store.

Preparation, uses, and tips

Due to their stable chemical nature, monounsaturated oils are suitable for low, medium, and high-temperature cooking. Olive oil, rich in flavor, is used frequently in marinades, sauces, and salad dressings. Canola oil has a milder flavor, which makes it good for baking. Peanut oil is often used in Asian cooking and to make salad dressings and sauces.

Nutritional Highlights

Canola oil, 1 Tbsp canola oil (15mL)
Calories: 124
Protein: 0.0g
Carbohydrate: 0.0g
Total Fat: 14g
Fiber: 0.0g
*Good source of: Vitamin E 3.0 IU

Olive oil, 1 Tbsp olive oil (15mL)
Calories: 119
Protein: 0.0g
Carbohydrate: 0.0g
Total Fat: 13.5g
Fiber: 0.0g

Peanut oil, 1 Tbsp peanut oil (15mL)
Calories: 119
Protein: 0.0g
Carbohydrate: 0.0g
Total Fat: 13.5g
Fiber: 0.0g

*Foods that are an “excellent source” of a particular nutrient provide 20% or more of the Recommended Daily Value. Foods that are a “good source” of a particular nutrient provide between 10 and 20% of the Recommended Daily Value.

Health benefits and concerns

Atherosclerosis

People who eat diets high in alpha-linolenic acid (ALA), which is found in canola and flaxseed oil, have higher blood levels of omega-3 fatty acids than those consuming lower amounts; this may confer some protection against atherosclerosis. In 1994, researchers conducted a study in people with a history of heart disease, using what they called the “Mediterranean” diet. The diet was significantly different from what people from Mediterranean countries actually eat, in that it contained little olive oil. Instead, the diet included a special margarine high in ALA. Those people assigned to the “Mediterranean” diet had a remarkable 70% reduced risk of dying from heart disease compared with the control group during the first 27 months. Similar results were also confirmed after almost four years. The diet was high in beans and peas, fish, fruit, vegetables, bread, and cereals, and low in meat, dairy fat, and eggs. Although the authors believe that the high ALA content of the diet was partly responsible for the surprising outcome, other aspects of the diet may have been partly or even totally responsible for decreased death rates. Therefore, the success of the “Mediterranean” diet does not prove that ALA protects against heart disease.

Hyperthyroidism

Some foods, such as rapeseed (used to make canola oil), contain natural agents, called “goitrogens,” that interfere with thyroid hormone synthesis. This could theoretically cause a hypothyroid condition, but it has not been demonstrated in humans.

Health benefits and concerns for fats and oils
Many health benefits and concerns associated with this food are applicable to other fats and oils. Read about health benefits and concerns for fats and oils for a full description.