When you think about olive oil, one adjective probably comes to mind: healthy. And you’re not wrong. Plenty of studies support that conclusion. Research suggests that specifically extra virgin olive oil (EVOO) may help reduce the risk of heart disease, stroke, type 2 diabetes and osteoporosis. But in the midst of all the positive press, there are also some controversies and concerns surrounding olive oil. Here’s my take on three buzzy topics, plus some advice for reaping the benefits of EVOO while avoiding the risks.
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Olive oil fraud is common
You may have seen a recent 60 Minutes report that exposed rampant fraud in the olive oil industry, due to Mafia corruption. Investigators concluded that as much as 80% of the olive oil sold as EVOO in the U.S. is not truly extra-virgin. Instead, some are mixed or lower-quality olive oils. Others may not be olive oil at all, but rather another type (like sunflower, canola, or soybean) with added coloring and flavoring so it mimics the real thing. Buying fake EVOO is like purchasing a fancy bottle of wine that turns out to be grape juice!
What do to: This doesn’t mean you should give up on EVOO; just do a little sleuthing before you buy. For starters, high-quality EVOO isn’t cheap. So if a bottle is a bargain, you should probably be suspicious. Next, look at where the oil was produced. One UC Davis report randomly tested bottles from retail stores and found nearly 70% of imported EVOO didn’t pass their purity test, while only 10% of California-produced oil failed. (Keep an eye out for the California Olive Oil Council seal, which requires olive oil to meet stricter standards than those set by the USDA.) If you’re interested, check out the full report, which includes a list of popular brands the university tested.
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How you cook with EVOO can impact your health
A brand new study published in the journal Food Chemistry revealed that cooking veggies in olive oil improves their nutritional value. Researchers found that the effect is two-fold: EVOO contains its own antioxidants and thereby increases overall antioxidant levels, and cooking with the oil increases your body’s ability to absorb antioxidants from the veggies.
However, there’s debate among health professionals about whether EVOO should be heated at all. Many believe EVOO shouldn’t be used in cooking because it has a low smoke point—the temperature at which heated oil begins to smoke continuously, triggering the production of harmful by-products. But since EVOO’s smoke point is close to 400 degrees Fahrenheit, it can safely be used in sautéing and even oven roasting without smoking.
But even if it is safe, some research shows that heating olive oil below the smoke point, especially for longer lengths of time, may diminish some of its natural anti-inflammatory powers. However, the effect may be minimal. One study found that when EVOO samples were heated at 180 degrees for 36 hours (yup 36, not 3-6), they still retained most of their nutritional benefits.
What to do: I advise my clients to eat lots of raw veggies, dressed with unheated EVOO-based vinaigrettes or combined with other healthy plant-based fats like avocado and almonds. However, I don’t think it’s necessary to refrain from using EVOO in cooking completely, as long as it’s used at lower temperatures and for a short durations of time, in order to best preserve its beneficial properties.
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The age and treatment of EVOO affect its benefits
Recently, while looking through a client’s pantry, I asked her how long she’d had a bottle of EVOO. She replied: “Mmmm, I don’t know, maybe six months?” She had no idea at the time, but that’s too long to keep an opened bottle. When it comes to EVOO, freshness matters a lot. EVOO can start to break down due to air, light or heat exposure (including sitting on the countertop near a range). When this occurs, it produces unhealthy substances that can trigger artery hardening and cell damage in your body. This kind of breakdown also lowers the smoke point of the oil, which means it’s more likely to produce harmful substances.
What to do: First, look for the date of the harvest (any quality brand will include this on the label), and buy the freshest bottle possible (within one year, ideally less). Also, be sure to buy an EVOO bottled with tinted glass, since light can trigger oxidation. Then, whenever you use your oil, pour a little out and give it a sniff. A quality oil should smell fruity, while one that’s going bad may smell stale or have an aroma of crayons or glue. Finally, be sure to store your EVOO in a cool, dark space. Use it up within six weeks and never reuse it after it’s been heated. These rules may seem overly cautious, but they’re well worth the effort to maximize the health perks of your oil.
Cynthia Sass is a nutritionist and registered dietitian with master’s degrees in both nutrition science and public health. Frequently seen on national TV, she’s Health’s contributing nutrition editor, and privately counsels clients in New York, Los Angeles, and long distance. Cynthia is currently the sports nutrition consultant to the New York Yankees, previously consulted for three other professional sports teams, and is board certified as a specialist in sports dietetics. Sass is a three-time New York Times best-selling author, and her newest book is Slim Down Now: Shed Pounds and Inches with Real Food, Real Fast. Connect with her on Facebook, Twitter and Pinterest.