This article will review the health and cooking properties of oils available in markets.
With so many cooking oils to choose from, it can be confusing which ones are heart-healthy and which ones are not. Cooking oils include plant, animal or synthetic fats used in frying, baking and other types of cooking. Oils are also used as ingredients in commercially prepared foods, and condiments, such as salad dressings and dips. Although cooking oils are typically liquid, some that contain saturated fat such as coconut oil, palm oil and palm kernel oil are solid at room temperature.
Health and Nutrition
The Food and Drug Administration recommends that 30% or less of calories from the foods you eat daily should be from fat and fewer than 7% from saturated fat. Saturated fat is found in animal and dairy products as well as the tropical oils (coconut, palm and palm kernel oil). The National Heart, Lung and Blood Institute and World Heart Foundation have recommended that saturated fats be replaced with polyunsaturated and monounsaturated fats. Olive and canola oils are good sources of monounsaturated fats while soybean and sunflower oils are rich in polyunsaturated fat. Oils high in unsaturated fats may help to lower ”bad” Low density lipoprotein (LDL) cholesterol and may raise “good” High density lipoprotein (HDL) cholesterol.
Omega- 3 and Omega- 6 Fatty Acids
Omega-3 and Omega-6 are essential fatty acids – we cannot make them on our own and must get them from the foods we eat. Both are polyunsaturated fatty acids that differ from each other in their chemical structure. In modern diets, there are few sources of Omega -3 fatty acids, mainly the fat of cold water fish such as salmon and sardines. Vegetarian sources such as walnuts and flaxseeds contain a precursor of Omega-3 that the body must convert to a useable form. Keep in mind that Omega-3 fats from marine sources, such as fish and shellfish have much more powerful health benefits than Omega-3 fats from plant sources. By contrast, there are abundant sources of Omega-6 fatty acids in our diets. They are found in seeds and nuts and the oils extracted from them. Refined vegetable oils, such as soy oil, are used in most of the snack foods, cookies, crackers and sweets in the American diet as well as in fast food. Most Americans get far too much Omega-6 and not enough Omega-3 so it is recommended to eat more foods containing Omega-3 fatty acids.
Trans Fats
Unlike other dietary fats, trans fats are not essential and they do not promote good health. Consumption of trans fats increases one’s risk of heart disease by raising levels of “bad” LDL cholesterol and lowering levels of “good” HDL cholesterol. Trans fats are artificially created by the process of hydrogenation that turns liquid oils into solid fats. Trans fat formed naturally is found in small amounts in some animal products, such as meat and dairy products. In 2015, the Food and Drug Administration, took action to significantly reduce the use of partially hydrogenated oils. Trans fats formed artificially during food processing are often found in commercial baked goods, crackers, and fried foods, as well as shortening and some margarines. When the label of ingredients says “partially hydrogenated”, it’s probably likely to contain trans fats. The Nutrition Facts label lists trans fats per serving.
Cooking with Oil
Heating oil changes its characteristics so it is important to know the smoke point – the point at which an oil begins to break down structurally, producing unhealthful by-products such as free radicals. Oils that are healthy at room temperature can become unhealthy when heated above certain temperatures. When choosing a cooking oil, it is important to match the oil’s heat tolerance with the cooking method. Generally, the more refined the oil, the higher it’s smoke point.
High Smoke Point (Best for searing, browning and deep frying)
| Oil | % Mono | %Poly | % Saturated | Notes |
| Almond | 65 | 28 | 7 | Has a distinctive nutty flavor; don’t use if allergic to nuts |
| Avocado | 65 | 18 | 17 | Has a sweet aroma |
| Hazelnut | 82 | 11 | 7 | Bold, strong flavor; don’t use if allergic to nuts |
| Palm | 38 | 10 | 52 | High in saturated fat; not recommended. |
| Sunflower
(high oleic) |
82 | 9 | 9 | Look for high oleic versions – higher in mono-unsaturated fat. |
| Rice Bran | 47 | 33 | 20 | Very clean flavored and palatable |
| Mustard | 60 | 21 | 13 | Palatable |
| Tea Seed | 60 | 18 | 22 | Good for frying and stir-frying |
| “Light”/refined Olive | 73 | 11 | 14 | The more refined the olive oil the better its all-purpose cooking use. “Light” refers to color. |
Medium – High Smoke Point (Best suited for baking, oven cooking or stir frying)
| Oil | %Mono | %Poly | %Saturated | Notes |
| Canola | 62 | 31 | 7 | Contains good levels of Omega-3;good all-purpose oil |
| Grapeseed | 17 | 73 | 10 | High in Omega-6 |
| Macadamia nut | 84 | 3 | 13 | Bold flavor, don’t use if allergic to nuts |
| Extra virgin olive | 73 | 11 | 14 | Good all –purpose oil |
| Peanut | 48 | 34 | 18 | Great for stir frying, don’t use if allergic to nuts |
Medium Smoke Point (Best suited for light sautéing, sauces and low-heat baking)
| Oil | %Mono | %Poly | % Saturated | Notes |
| Corn | 25 | 62 | 13 | High in Omega-6, high mono-unsaturated versions coming. |
| Hemp | 15 | 75 | 10 | Good source of Omega-3. Keep refrigerated |
| Pumpkin Seed | 36 | 57 | 8 | Contains Omega-3 |
| Sesame | 41 | 44 | 15 | Rich nutty flavor, keep refrigerated |
| Soybean | 25 | 60 | 15 | High in Omega-6 |
| Walnut | 23 | 63 | 9 | Good source of Omega- 3 |
| Coconut | 6 | 2 | 92 | High in saturated fat; use in moderation. |
No – Heat Oils (Best used for dressings, dips or marinades)
| Oil | %Mono | %Poly | %Saturated | Notes |
| Flaxseed
(Linseed oil) |
21 | 68 | 11 | Excellent source of alpha-linoleic acid, a form of Omega -3 |
| Wheat germ | 65 | 18 | 17 | Rich in Omega-6. Keep refrigerated. |
Storage/Shelf Life
Different oils stay fresh for different amounts of time, but you must store them all carefully. They should be tightly covered and stored in the dark away from heat. The less access to air, the fresher they will stay. Refrigeration benefits most oils. If unopened, peanut oil, corn oil, and other vegetable oils will keep for at least a year. Once opened, they are good for 4-6 months. Olive oil will keep for about 6 months in a cool, dark pantry but up to a year in the refrigerator. Walnut oil and sesame oil are delicate and inclined to turn rancid. Keep in the refrigerator and they will stay fresh for 2-4 months. It is best to purchase smaller bottles of oil if not used extensively.
Proper Disposal of Used Cooking Oil
Proper disposal of used cooking oil is an important waste-management concern. A single gallon of oil can contaminate as much as 1 million gallons of water. Oils can congeal in pipes causing major blockages. Cooking oil should never be dumped in the kitchen sink or in the toilet bowl. The proper way to dispose of oil is to put it in a sealed, non-recyclable container and discard it with regular garbage.
Article by: Sherry Gray MPH, RD
Extension Educator, UConn EFNEP
Updated: 10/1/19
Sources:
https://www.accessdata.fda.gov/scripts/InteractiveNutritionFactsLabel/factsheets/Trans_Fat.pdf
https://www.accessdata.fda.gov/scripts/InteractiveNutritionFactsLabel/factsheets/Total_Fat.pdf
Wikipedia.org/wiki/cooking-oil
Health.clevelandclinic.org/2012/05/heart-healthy-cooking-oils-101/
www.hsph.harvard.edu/nutritionsource/healthy-fats/
whatscookingamerica.net/information/cookingoiltypes.html