Science takes stock of the bottles in your pantry
"This article clarified questions that I had and provides guidance. It is this type of article (as opposed to recipes) that makes Eating Well such a good magazine and one of the few for which I want a subscription. It was this month's...
When Artemis Simopoulos landed in the United States from Kalamata, Greece, in 1949, one of the most profound shocks, and something she has never forgotten, was American food. “The white bread—to me, it was like cotton!” she exclaims, in an accent that retains its Greek roots. “The bright yellow cheese, it was like plastic. The apples looked beautiful, but they had no taste. And chicken à la king! I just could not eat it.” Equally baffling, she found, was the national disdain for olive oil.
“At that time, everybody said it was too oily, too heavy,” she recalls. “We were told that safflower oil was healthier because it was lighter.”
Undaunted, Simopoulos continued to drizzle olive oil on her salads. It was later, as a researcher at the National Institutes of Health, that her studies on omega-3 fatty acids helped put olive oil on its current pedestal. As she reported in The Omega Diet (HarperPerennial, 1999), the traditional eating pattern of the Mediterranean island of Crete—abundant in vegetables, fruits and fish, low in red meat, and liberally doused in extra-virgin olive oil—is associated with astonishingly low rates of heart disease and cancer.
“Nowadays, everybody feels comfortable using olive oil,” she laughs.
As for safflower oil? Once so revered by health researchers that people gulped daily shot glasses full, it fell from nutritional grace as fast as olive oil’s star rose. In fact, the safflower seed had to have a facelift—a hybrid makeover of its fatty-acid profile—before its oil could make a comeback in the minds of the health-conscious.
The turnaround in olive oil’s fortunes—and safflower’s, for that matter—is one reason we feel so confused when we push our grocery carts through the oils section of the supermarket. Where once there were just a few spare choices of culinary oils, a veritable thicket of options has now grown—virtually all claiming to be healthy. There are oils extracted from rapeseed and corn and soy and pumpkinseed, from peanuts and tea seeds, macadamia nuts and hemp seeds. Even coconut and palm oils—the so-called tropical oils once accused by nutrition crusaders of “poisoning America”—are now making noises in their advertising that they are healthy for you. Sifting through the hype to the truth is no simple task.
First, the good news: no matter which cooking oil you select, pat yourself on the back for choosing a liquid over a solid fat, such as shortening or butter. It’s a fairly safe bet that by doing so, you avoid saturated animal fats and trans fats, the undeniable nutritional bad guys. Multitudinous clinical and epidemiological studies confirm that high intakes of saturated fats and trans fats cause cholesterol and heart-disease risk to rise—and that when unsaturated fats replace saturated fats in the diet, those risks are largely averted.
“Replacing saturated fats with unsaturated fats is a safe, proven and delicious way to cut the rates of heart disease,” claims Harvard researcher Walter Willett. So every effort you make to substitute oils for solid fats is a step in the right direction. It would not be overstating the case to say that the oils you choose to eat, day in and day out, can play a major role in your health future.
Now, the tricky part: each oil is different from the others, and often with its own nutritional profile and culinary uses. To choose wisely you need to pick the right oil for the job. Even Simopoulos, now with the Center for Genetics, Nutrition, and Health, has expanded her oil repertoire beyond the extra-virgin olive oil that she brings back from the estate groves of her family’s ancestral home. For many people, narrowing the choices down to just three bottles in the kitchen can answer most needs (see chart).
Essential Oil Chart
What about the fats?
All oils are combinations of three types of fatty acids: monounsaturated, polyunsaturated and saturated. The characteristics of an oil are mainly determined by the fatty acid that predominates in the mix: olive oil is about 78 percent monounsaturated fat, for example, so it falls in the mono-fat camp. Soybean oil is just over 60 percent polyunsaturated and thus considered a poly fat. (Saturated fats, negligible in most oils, don’t usually figure much in the mix—except in coconut and palm oils.)
Most cardiologists and nutritionists sing the praises of high-mono oils like olive and canola because monos are especially vital in heart health—keeping damaging LDL cholesterol low, while boosting levels of cholesterol-clearing HDLs. But our hearts are not the only beneficiaries. In countries where high-mono fats predominate in the diet, rates of some cancers are remarkably low. No wonder plant geneticists rushed to develop high-mono hybrids of safflower and other traditionally low-mono oilseeds, by boosting their content of heart-friendly oleic acid. High-oleic sunflower and safflower oils are now widely available, and high-oleic corn oil isn’t far behind.
Since heart disease is North America’s top killer, it makes sense, then, to make high-mono fats like olive and canola your staple oils, with peanut oil (with its high-heat tolerance) running close behind. “They should be your primary fats,” says Simopoulos, who now uses a half-and-half blend of extra-virgin Greek olive oil and canola oil “for everything.” If you can afford them, avocado, macadamia nut, tea and almond oils are also good mono-rich choices for everyday use.
What about poly fats?
Though mono-fat oils should have front-row placement in your pantry, some researchers claim there are good reasons to save space on the second shelf for corn oil, soybean oil and other oils with higher levels of polyunsaturated fats. Poly-fat oils are often good sources of essential fatty acids, including the sought-after omega-3s, and—perhaps their most important attribute—they also reduce LDL cholesterol.
In reviewing the results from the 80,000-plus women studied through the Nurses’ Health Study, Harvard researcher Frank Hu noted that those women who used the most salad dressings—including mayonnaise-based types, which are high in poly-rich soybean oil—had half the risk of fatal heart disease as those who rarely used dressings even when the differences in the amount of vegetables they ate were factored out. Those findings and others, he noted, suggest that replacing saturated fats—and especially trans fats—with poly-fats “is likely to substantially reduce the risk” of heart disease.
Organic or not?
Having an “organic” label on the oil you choose is a guarantee that the crops grown to produce it—whether olive, rapeseed (canola) or soybean—were raised without using pesticides. It’s also a pretty safe guarantee that the oil will cost more—sometimes twice as much. Is it worth it? “It’s really an environmental decision rather than a health decision,” says Mark Kantor, a food scientist at the University of Maryland, and a nutrition communicator with the Institute of Food Technologists. Kantor, who regularly reads federal pesticide surveillance reports, notes that “pesticide residues in food oils are negligible.” Organic oils are also certified to be free of genetically modified content, which you may choose to avoid.
What about smoke point?
If you plan to cook at high heat—say, frying, grilling or searing—an oil’s smoke point is an important consideration. When oils are heated to the point that they literally smoke, they begin to break down and their chemical structure changes shape. Nutrients are destroyed and potentially carcinogenic hydrocarbon compounds can form, making the oil and the smoke it produces noxious. You should therefore eye with suspicion any recipe that begins “heat oil until it begins to smoke”—and discard any oil that’s been subjected to this indignity. (Though frugal cooks may object, it’s best not to re-use cooking oil, for the same reasons.) For high-heat cooking, look for an oil on the chart (see chart) with a high smoke point.
How was the oil extracted?
Unless they’re organic or advertise otherwise, most oils are extracted using chemical solvents, such as hexane; the solvents and their residues are then removed from the oil. This process, though cheap, is disturbing to those who don’t want a petrochemical derivative used in the making of their foodstuffs.
“Hexane has some pretty serious environmental side effects,” claims Neil Blomquist, president of Spectrum Natural Products, a national producer of natural and organic culinary oils. And, while virtually all traces of the solvent are technically removed, he adds, “even small amounts of residue matter, because they can accumulate in the body over time.”
Environmentally oriented folks, then, might gladly pay a little more for oils labeled “expeller-pressed.” Extracting these oils is simply a matter of crushing the seeds or fruit in a screw-type press, sometimes with a little heat added to make the process more efficient. Because this extraction method yields only about 50 to 70 percent of the oil from the seed, the resulting oils are more expensive. The term “cold-pressed,” though not standardized, usually suggests that the oil was expeller-pressed under conditions without heat—an important consideration when an oil is especially sensitive to heat, such as flaxseed oil.
What about refinement?
Refinement is the process of preparing a first-pressed oil, or crude oil, for consumption by removing color pigments, free fatty acids, phospholipids, parts of the seed, and dirt. The objective is a clear, uniform, shelf-stable product with a wide market appeal.
The benefit: Refined oils generally have a longer shelf life and thus will go rancid less quickly. They also tend to be more heat stable than unrefined oils, which means you can use them to cook at higher temperatures without the risk of breaching the oil’s smoke point. Refined oils have a clear appearance and a neutral flavor and odor.
The downside: Some health benefits can be destroyed or removed during refinement. “If you have a choice between buying a refined oil and a virgin oil (unrefined), buy the less refined,” says Atif Awad, a biochemist at the State University of New York at Buffalo. Unrefined oils are apt to be higher in antioxidant polyphenols and in phytosterols, essential plant fats known to lower cholesterol and inhibit cancer.
What about taste?
While this attribute seems obvious, it’s easy to overlook when you’re focusing on making a healthy oil choice. But fats aren’t medicine—they are key flavor carriers in foods, so taste matters significantly. You may want an oil that tastes deeply of the seed it came from; toasted sesame oil or roasted peanut oil in an Asian dressing come to mind. If you want no flavor to come between you and what you are cooking or baking, neutral-flavored grapeseed oil, canola or avocado oils might fit the bill.
Whatever you choose, let the oil enhance your pleasure in the foods you create. Without that, it’s all just, well, grease.
—Joyce Hendley is the nutrition editor of EatingWell.
Coconut and Palm Oils
Some data suggest that the saturated fat in palm and coconut oils is not like the saturated fat in meat and metabolizes more like an unsaturated fat in the body, causing no increase in LDL cholesterol. Some proponents even suggest that these tropical oils may offer beneficial effects, such as reducing inflammation. However, many scientists remain reluctant to give a highly saturated vegetable oil the thumbs-up.
The Canola Controversy
Ever since it hit the market back in 1985, canola oil has been the center of a debate. While most health professionals now recommend canola oil to consumers for its healthy fat profile, some critics remain wary because of the oil’s questionable origins and high refinement.
The mother of canola is the rapeseed, a plant dense with monounsaturated fats that benefit our health, but also high in erucic acid, a powerful agent used for industrial purposes. Because erucic acid is toxic at certain levels, plant breeders in Canada developed a rapeseed hybrid, calling it “canola,” with less than 1 percent erucic acid. “At these levels the FDA has determined that erucic acid presents no threat to the consumer,” says Penny Kris-Etherton, a researcher at Pennsylvania State University who specializes in oils and fats in the diet.
Among the commonly available oils, canola comes second to olive oil in monounsaturated fats but canola is less expensive to produce. It is naturally rich in alpha linoleic acid (ALA), says Kris-Etherton, explaining that ALA (part of the omega-3 family) makes blood platelets less sticky and thus less likely to clog arteries.
While its low cost and impressive health properties may tempt you to use canola oil for all your cooking needs, that doesn’t mean you should. Some health properties can be destroyed during refinement of the seed, and unless the label specifically notes the nutrients, says lipid biochemist Mary Enig, author of Know Your Fats (Bethesda Press, 2000), they may be compromised.
Other experts are less concerned by refinement. “I use canola oil a lot but I try to use a variety of liquid vegetable oils when I’m cooking—they all have different health attributes,” Kris-Etherton says.
Making Oil Choices: The Top 3 Picks
This flavorful, heart-healthy oil is unrefined and thus high in antioxidants and polyphenols that are a tonic to cardiovascular health. Less expensive but so-called “pure” olive oil (not extra-virgin) is refined and more tolerant to heat but also less nutrient-dense. Don’t bother with “light” olive oil; it has virtually no character and even fewer polyphenols. Use extra-virgin in low-heat cooking, baking and dressings.
High in omega-3s, this practical bland oil with a relatively high smoke point can be used for sautéing and baking. Most canola oil is highly refined to extract as much oil as possible from the seed. The resulting inexpensive version has a long shelf life. Some consumers choose to pay more for less refined organic canola oil. The organic designation guarantees that the seed was not from genetically modified plants.
This specialty oil sports a higher price tag, but along with a rich, nutty flavor come omega-3s and vitamin E. Close runners-up in this category include toasted sesame, pumpkinseed and almond oils. We chose walnut as a top pick because of its relatively long shelf life: three months when refrigerated. Use it to dress salads, especially those containing flavorful cheese and nuts.
Clouds in Your Oil?
Don’t reject that murky oil. Its translucence is a clue to beneficial phytosterols. Unfortunately, says biochemist Atif Awad, you won’t find as many in refined oils.
Is Butter Better?
I studied nutrition at the height of the fat-phobic ’90s—so one day, when an astute professor asked which of us dietitians-in-training used margarine instead of butter, I was sure all the hands in the room would go up. Not a single one did. Even then, we were a room full of butter lovers. And no doubt more among our ranks have since moved into the pro-butter camp, as the almost daily indictments of trans fats make margarine look more like foe than friend. But most healthy cooks I know treat butter as a dear but distant pal, who comes only occasionally for brief visits.
“I subscribe to the ‘a little goes a long way’ school,” says EatingWell Food Editor Patsy Jamieson, who drizzles it sparingly in recipes where buttery flavor is critical.
Even though butter doesn’t contain those trans fats, it’s still a potent source of saturated fat—nearly 70 percent. That’s even more than lard (43 percent) and duck fat (33 percent). Choosing butter made from the milk of grass-fed cows improves the situation slightly—it has higher levels of heart-healthy omega-3 fatty acids and conjugated linoleic acid (CLA), a so-called “good fat” that has shown promise in preliminary studies of rheumatoid arthritis. However, nobody’s about to call butter a health food.
Luckily butter, unlike margarine, has the gift of wonderful, irreplaceable flavor that works miracles in small amounts—as creative cooks like Jamieson have found. For baking, she beats canola oil into softened butter to thin it with healthier fats (a feat duplicated by the Land O’Lakes company in its new “Soft Baking Butter with Canola Oil”). And swirling a tiny nub of butter into a pan sauce at the end of cooking “can work wonders,” she adds.
Indeed, nutritionists and foodies alike agree that life without a little butter would be bleak. “If I live to be 80-plus,” exclaims healthy-cookbook author Marie Simmons, “I’ve decided I’m going to slather butter on my toast again.”
The Omega Balance
Without question, each of us needs omega-6 and omega-3 fatty acids in our diet. But the balance between the two has recently become the center of a hot debate.
These two key polyunsaturated fats are called “essential fatty acids” because our bodies can’t manufacture them; they must come from the foods we eat. Each has its own actions in the body, often opposing each other: omega-6s, for example, are converted in the body to substances that assist in responding to inflammation and bleeding; omega-3s, by contrast, convert to substances that slow blood clotting and decrease inflammatory responses. Together, they work as a check-and-balance system of sorts, and some researchers argue that our modern Western diets have thrown that balance out of whack.
Throughout most of human history, since our Paleolithic ancestors first hunted game, speared fish and gathered wild greens, humans have eaten a diet that kept the omega-6 to omega-3 balance fairly equal—“close to a 2 to 1 ratio,” notes Artemis Simopoulos, co-author of The Omega Diet. This pattern continues in the traditional diet of Crete, where heart disease and cancer rates are among the lowest in the world.
But in the United States, omega-6 fatty acids now dominate the ratio because people are eating more processed foods, such as chips and packaged cookies, which are made with high-omega-6 oils like soybean or cottonseed. Our meats, poultry and dairy products have also become more omega-6 heavy as we feed our animals grains instead of grasses. Today, the omega-6 to omega-3 ratio hovers around 17 to 1, says Simopoulos, explaining that this imbalance is a key contributor to the modern plague of heart disease. “Major dietary studies have shown that when people are fed diets that lower this ratio, their death rates from heart disease fall significantly.”
Not everyone agrees that increased omega-6s threaten our health, however. Frank Hu, of the Harvard Nurses’ Health Study, argues that omega-6s also have beneficial effects on heart-disease risk. “Because omega-6 has very strong LDL-lowering effects, it actually lowers the LDL to HDL ratio, which is the most powerful predictor of heart disease.” Reducing omega-6 levels, then, would take away some of those benefits.
Although he is skeptical, Hu suggests the following for anyone who wants to lower their omega-6 to omega-3 ratio: focus on getting more omega-3s, rather than cutting omega-6s, by eating more fish, freshly ground flaxseeds and walnuts, and by using oils that provide omega-3s, like canola and walnut.
Simopoulos counters, “If you have too many omega-6s, you can’t use omega-3s as efficiently. To get the full benefit of omega-3s, you must lower the omega-6 to omega-3 ratio.” She recommends following a dietary pattern similar to that of the traditional diet of Crete: vegetable-and-fruit laden, low in saturated fats, generous in omega-3s and stingy with omega-6s. “It is the diet on which humans evolved, and which our genetic profile has adapted to.”