Face the fats
September 14, 2004 | 12:00am
I still don’t know what kind of oil to buy," says Editha Senupe, of Marikina City. "Some people recommend monos, like olive or canola oil. Others say polys, like soybean or corn oil, are better. With advice about fats changing so frequently, I’m confused."
Ms. Senupe isn’t the only one to get that glazed look whenever she’s in the oil aisle. Who wouldn’t be confused with the steady stream of mixed messages?
Diet books range from virtually fat-free (Ornish) to high-fat (Atkins). The media publish conflicting reports on saturated, monounsaturated, polyunsaturated, trans, omega-3, and other fats. Ads plug fish oil, DHA, and flaxseed oil supplements to boost immunity, memory and healthy circulation. Here’s what you need to know about fats – and what you can ignore.
Strictly speaking, all fats are a mixture of saturated, monounsaturated and polyunsaturated fatty acids. However, we usually call them by the name of the fatty acid they have the most of. The bad fats are saturated and trans. The better fats are monos and polys. And the best fats are the omega-3s. The good oils are those with the least saturated fats and a good mixture of mono, poly and other fats (e.g. safflower, canola, flaxseed, sunflower, corn and olive oils).
Polys lower cholesterol, while monos only lower cholesterol if you eat them in place of saturated fats. Linoleic acid and alpha-linolenic acid are examples of polyunsaturated fats. Alpha-linolenic acid is an omega-3 polyunsaturated fat that may protect the heart. Canola, soy and flaxseed oil are good sources. Linoleic acid is polyunsaturated omega-6 fat. Many researchers recommend a mix of alpha-linolenic acid and linoleic acid. If you don’t want the details, just stick with canola for cooking. It’s among the lowest in saturated fat and it has a good mix of alpha-linolenic and linoleic acids.
Saturated fat occurs naturally in nearly all fatty acids, but mostly in meats, dairy products, and tropical oils like palm kernel and coconut. Most trans fats are created when manufacturers turn liquid oils into more solid fats like shortening and margarine.
The evidence against both fats is strong. "It’s not a question of choosing which artery-clogging fat to avoid," says Meir Stampfer of Harvard School of Public Health. "People should cut down on both saturated and trans fat."
"Technically, trans is worse than saturated fat, because saturated fat raises both LDL ("bad") cholesterol and HDL ("good") cholesterol, while trans only raises LDL," explains Alice Lichtenstein of the Human Nutrition Research Center at Tuft’s University in Boston. "But if you have to target one fat for modification, there’s a greater potential for change by cutting saturated fat," she adds. That’s because only 2 percent of our calories come from trans fat, while sat fat contributes 13 percent. Avoiding sat fat is a tough job because it’s in so many popular foods, from pizza and hamburgers to steak, tacos, ice cream, lasagna and cheese. But Lichtenstein admonishes, "The message needs to be loud, it needs to be clear, and it needs to be unequivocal: Limit your intake of both saturated and trans fats."
In the early 1970s, corn oil was king. Researchers then found that highly polyunsaturated fats (like corn, soy and sunflower oil) could lower cholesterol. In contrast, highly saturated fats (like butter and beef) raised cholesterol, while highly monounsaturated fats (like canola and olive oil) were neutral. But by the1990s, the pendulum swung towards monos. In part, the enthusiasm was fueled by lavish conferences for researchers and the media sponsored by the olive oil industry. The science looked promising, too. For example, it was found that unlike polys, monos don’t lower HDL, the so-called good cholesterol. Subsequently, however, researchers rediscovered that polys have more power to lower cholesterol than monos.
Does this mean that people should spill out all their olive and canola oil and rush to the store for soy oil? Not quite. First of all, some dishes taste better with certain oil. "At home, we use olive oil for salad dressing because the taste matters," says Stampfer. "We bake with canola. And we also use sesame, peanut and safflower, depending on the dish."
Taste aside, if you’re like most people, the oil you buy is just a small fraction of the fat you eat. What’s in your bottled salad dressing and mayonnaise? What’s in the spaghetti sauce, muffins, cookies or other foods in your pantry? And don’t forget restaurants. What oil does your favorite Chinese takeout use? What greases the griddle when you order chicken or shrimp fajitas? What went into that spicy peanut sauce, vinaigrette or clam sauce?
The odds are it’s soy. A growing body of evidence suggests that it makes sense to balance all that soy by using mostly canola at home. "I buy about three bottles of canola for every bottle of soy," says Lichtenstein. Why? The soy oil adds cholesterol-lowering polys. But canola is the mainstay because it’s very low in saturated fat and has a good dose of polys (more than olive oil). What’s more, canola’s omega-3 fats may help protect your heart, though the evidence is stronger for omega-3 fats that come from fish.
Unlike polyunsaturated vegetable oils, polyunsaturated fish oils have always had a stellar reputation. And two years ago, the news got even better. "Three new studies showed that omega-3 fats in fish oil protected people from sudden death," says Stampfer, who co-authored two of them. (In sudden cardiac death, which causes half of all heart disease deaths, the heartbeat goes awry and then stops. Most victims have clogged coronary arteries.)
Exactly how fish oils work isn’t certain. The leading theory: When the heart is under severe stress, a key fish fat stabilizes heart cells, which allows the heart to maintain its regular beat. (The fat is likely to be eicosapentaenoic acid, or EPA. DHA, or docosahexaenoic acid, is the other key fish fat.) "When there’s trouble, EPA is released from the cell membrane and it suppresses the extra heartbeats," says William Connor of the Oregon Health and Science University in Portland. At higher doses, omega-3 fats may also protect the heart by lowering triglyceride levels and preventing blood clots.
In any case, the take-home message is to eat more seafood. The American Heart Association now recommends at least two servings per week, preferably of fatty fish. But if you want to make sure you’re getting enough omega-3 fats, shoot for between 1/2 and 1 gram (500 and 1,000 mg) a day. If you don’t eat seafood, there are other options. Among them: Alpha linolenic acid and omega-3 that’s largely found in flaxseed, canola and soy oils as well as walnuts and soybeans.
"The best alternative to seafood is to get both DHA and EPA from fish oil pills or from fish oil that’s been added to other foods," says omega-3 expert Bruce Holub of the University of Guelph in Canada. But be careful. Fish oil pills can cause side effects. For example, getting more than three grams (3,000 mg) of EPA and DHA a day from foods and supplements may raise the risk of hemorrhagic stroke.
1) Cut your intake of saturated plus trans fat to less than 10 percent of calories or about 20 grams a day of both combined.
2) At home, use canola oil as your main oil with a variety of others for taste.
3) Shoot for between 1/2 and 1 gram (500 and 1,000 mg) a day of omega-3 fats (DHA and EPA) from one of the following:
• Consume seafood two to five times a week.
• If you take fish oil pills, there’s no reason to take more than 2 gram a day of EPA and DHA combined. More than 3 grams may increase the risk of bleeding or hemorrhagic stroke.
• If you’re a vegetarian, you can get DHA (but not EPA) from supplements made from algae. Or you can get alpha linolenic acid from walnuts, soybeans, or flaxseed, canola, or soy oils, though the body doesn’t convert much of it into EPA and DHA.
• Lastly, remember this about fats: When it comes to obesity, all fats are suspect because all are equally high in calories. When it comes to cancer, no fat appears to be at fault. And as far as heart disease and stroke are concerned, it’s not how much fat that matters. It’s how much of which fat that is crucial!
Ms. Senupe isn’t the only one to get that glazed look whenever she’s in the oil aisle. Who wouldn’t be confused with the steady stream of mixed messages?
Diet books range from virtually fat-free (Ornish) to high-fat (Atkins). The media publish conflicting reports on saturated, monounsaturated, polyunsaturated, trans, omega-3, and other fats. Ads plug fish oil, DHA, and flaxseed oil supplements to boost immunity, memory and healthy circulation. Here’s what you need to know about fats – and what you can ignore.
Polys lower cholesterol, while monos only lower cholesterol if you eat them in place of saturated fats. Linoleic acid and alpha-linolenic acid are examples of polyunsaturated fats. Alpha-linolenic acid is an omega-3 polyunsaturated fat that may protect the heart. Canola, soy and flaxseed oil are good sources. Linoleic acid is polyunsaturated omega-6 fat. Many researchers recommend a mix of alpha-linolenic acid and linoleic acid. If you don’t want the details, just stick with canola for cooking. It’s among the lowest in saturated fat and it has a good mix of alpha-linolenic and linoleic acids.
The evidence against both fats is strong. "It’s not a question of choosing which artery-clogging fat to avoid," says Meir Stampfer of Harvard School of Public Health. "People should cut down on both saturated and trans fat."
"Technically, trans is worse than saturated fat, because saturated fat raises both LDL ("bad") cholesterol and HDL ("good") cholesterol, while trans only raises LDL," explains Alice Lichtenstein of the Human Nutrition Research Center at Tuft’s University in Boston. "But if you have to target one fat for modification, there’s a greater potential for change by cutting saturated fat," she adds. That’s because only 2 percent of our calories come from trans fat, while sat fat contributes 13 percent. Avoiding sat fat is a tough job because it’s in so many popular foods, from pizza and hamburgers to steak, tacos, ice cream, lasagna and cheese. But Lichtenstein admonishes, "The message needs to be loud, it needs to be clear, and it needs to be unequivocal: Limit your intake of both saturated and trans fats."
Does this mean that people should spill out all their olive and canola oil and rush to the store for soy oil? Not quite. First of all, some dishes taste better with certain oil. "At home, we use olive oil for salad dressing because the taste matters," says Stampfer. "We bake with canola. And we also use sesame, peanut and safflower, depending on the dish."
Taste aside, if you’re like most people, the oil you buy is just a small fraction of the fat you eat. What’s in your bottled salad dressing and mayonnaise? What’s in the spaghetti sauce, muffins, cookies or other foods in your pantry? And don’t forget restaurants. What oil does your favorite Chinese takeout use? What greases the griddle when you order chicken or shrimp fajitas? What went into that spicy peanut sauce, vinaigrette or clam sauce?
The odds are it’s soy. A growing body of evidence suggests that it makes sense to balance all that soy by using mostly canola at home. "I buy about three bottles of canola for every bottle of soy," says Lichtenstein. Why? The soy oil adds cholesterol-lowering polys. But canola is the mainstay because it’s very low in saturated fat and has a good dose of polys (more than olive oil). What’s more, canola’s omega-3 fats may help protect your heart, though the evidence is stronger for omega-3 fats that come from fish.
Exactly how fish oils work isn’t certain. The leading theory: When the heart is under severe stress, a key fish fat stabilizes heart cells, which allows the heart to maintain its regular beat. (The fat is likely to be eicosapentaenoic acid, or EPA. DHA, or docosahexaenoic acid, is the other key fish fat.) "When there’s trouble, EPA is released from the cell membrane and it suppresses the extra heartbeats," says William Connor of the Oregon Health and Science University in Portland. At higher doses, omega-3 fats may also protect the heart by lowering triglyceride levels and preventing blood clots.
In any case, the take-home message is to eat more seafood. The American Heart Association now recommends at least two servings per week, preferably of fatty fish. But if you want to make sure you’re getting enough omega-3 fats, shoot for between 1/2 and 1 gram (500 and 1,000 mg) a day. If you don’t eat seafood, there are other options. Among them: Alpha linolenic acid and omega-3 that’s largely found in flaxseed, canola and soy oils as well as walnuts and soybeans.
"The best alternative to seafood is to get both DHA and EPA from fish oil pills or from fish oil that’s been added to other foods," says omega-3 expert Bruce Holub of the University of Guelph in Canada. But be careful. Fish oil pills can cause side effects. For example, getting more than three grams (3,000 mg) of EPA and DHA a day from foods and supplements may raise the risk of hemorrhagic stroke.
2) At home, use canola oil as your main oil with a variety of others for taste.
3) Shoot for between 1/2 and 1 gram (500 and 1,000 mg) a day of omega-3 fats (DHA and EPA) from one of the following:
• Consume seafood two to five times a week.
• If you take fish oil pills, there’s no reason to take more than 2 gram a day of EPA and DHA combined. More than 3 grams may increase the risk of bleeding or hemorrhagic stroke.
• If you’re a vegetarian, you can get DHA (but not EPA) from supplements made from algae. Or you can get alpha linolenic acid from walnuts, soybeans, or flaxseed, canola, or soy oils, though the body doesn’t convert much of it into EPA and DHA.
• Lastly, remember this about fats: When it comes to obesity, all fats are suspect because all are equally high in calories. When it comes to cancer, no fat appears to be at fault. And as far as heart disease and stroke are concerned, it’s not how much fat that matters. It’s how much of which fat that is crucial!
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