Q: Are there any oils I should avoid totally?
Yes: The worst type of oil is an ingredient in packaged foods including some stick margarines, baked goods, chips, crackers and candy.
Q: For the record, which is better: butter or olive oil?
Olive oil is predominantly rich in heart-healthy monounsaturated fat, which decreases your risk for cardiovascular disease by lowering LDL cholesterol and increasing HDL cholesterol.
However, the distinctive smell, flavor and consistency of butter works best in certain baked goods—including cakes, cookies and pastries—so it’s OK to make these occasionally and enjoy the butter.
Q: What’s the difference between regular olive oil, virgin and extra-virgin?
Olive oil is made by crushing olives to make a paste that’s then put under a press. If the oil that comes out has a low acidity and a good taste and smell, it’s labeled extra-virgin or virgin. These types are ideal to use for bread dunking, drizzling on veggies and other foods, and making salad dressings, since their delicate flavor and aroma will be lost when heated (some chefs still prefer to use extra-virgin for cooking). The deeper the color, the more intense the olive flavor.
If the oil is highly acidic or not great quality, it’s refined and mixed with virgin or extra-virgin oil to make “regular” olive oil; this all-purpose oil is good for cooking.
The heart-health benefits of all types of olive oil are pretty much the same, although the virgin and extra-virgin ones have extra antioxidants.
Q: How can oils be healthy if they’re so fattening?
Oils may be “fattening” in the sense that they’re pretty high in calories compared with other foods. But since oils contain fats that are good for you, you’re better off getting that 120 calories from a healthy oil rather than stick or tub butter. We do need some fat to be healthy. Without it, our bodies can’t absorb fat-soluble vitamins like A, D, E and K, and we miss out on fatty acids that are essential for the health of your skin, hair, heart and brain—and just about every other part of your body.
Q: How should I store oils?
Heat, light and oxygen degrade oils, which makes them turn rancid more quickly and actually promotes the formation of cancer-causing compounds called free radicals. The more polyunsaturated fats an oil contains, the more susceptible to rancidity it becomes.
Oils rich in PUFAs, such as walnut and flaxseed, are best stored in the fridge in tightly capped containers. MUFAs, such as those found in olive oil, are a bit more hardy, but you should still protect oils that contain them by keeping the lid on tightly and storing them in a dark place far from the stove or other heat source. Saturated fats, such as butter, can withstand more heat, light and oxygen, but you should still refrigerate sat-fat–rich butter, because it contains milk solids, which can go rancid. If you store oils correctly, most will last about six months to one year.
When you’re shopping for oils, reach for bottles at the back of the shelf, since that’s where they are more protected from harsh lighting that can make them go bad. Check the bottle for an expiration date (most oils have one), and every time you open a bottle, give it a whiff to make sure it doesn’t smell rancid.
read article on Yahoo! Health by Joy Bauer, RD from Woman’s Day: Are Cooking Oils Good for You?