How to know if the olive oil you’re buying is actually good for you

Olive oil has many health benefits, including lowering the risk for dementia, poor heart health, cognitive decline or early death.

How beneficial the Mediterranean diet staple actually is depends on how the product is harvested, processed, stored and used — in farms or mills, grocery stores and your own home.

“The health benefits come from a variety of factors or components within olive oil,” said Dr. Tassos Kyriakides, assistant professor of biostatistics at the Yale School of Public Health in New Haven, Connecticut. “The main one is oleic acid, and that has been shown to have very healthful benefits.”

Also important is the rich amount of polyphenols in olive oil, which are a type of antioxidant that helps protect against cell damage and inflammation in the body, said Dr. Mercedes Fernández, head of the standardization and research unit of the International Olive Council, an intergovernmental organization based in Spain.

Here’s what you need to know to select the best possible olive oil for your diet.

Harvest and processing

Historically, brands that maintain a high quality of olive oil are those that put care into the process from the moment of harvest, Kyriakides said. Oil made from gently harvested, very green olives that haven’t fully ripened are best since those have a higher concentration of the healthful components, he added.

How quickly the olives go from harvest to being processed into oil is the next critical step.

“Some companies have their own mills and processing where within two hours, they could take the fruit from the trees, put it in the mill and get the product,” Kyriakides said. This minimizes the risk of the fruit oxidizing or fermenting from sitting out for too long post-harvest.

A worker pours harvested olives into the truck's silos to transport them to a mill in Molfetta, Italy, on December 2, 2020. - Davide Pischettola/NurPhoto/Getty Images
A worker pours harvested olives into the truck's silos to transport them to a mill in Molfetta, Italy, on December 2, 2020. - Davide Pischettola/NurPhoto/Getty Images

There shouldn’t be more than a few days between harvest and processing dates, he added.

How the oil is processed is one of the biggest factors in whether that product is healthy, experts say. Extra virgin olive oil is the healthiest version because it’s cold-pressed only once without high heat or chemical solvents. The special processing helps extra virgin oil retain its nutrients.

Freshness and storage methods

You may be wondering how you’re supposed to know when brands pick their olives or how soon they process them.

With the growing popularity of consuming olive oil for health benefits, some companies have placed these details directly on product labels. Alternatively, some labels have a QR code you can scan to read that information on your smartphone.

Either way, be sure to look for the harvest, processing and bottling dates and the “best by” date to get the freshest oil, experts recommend.

Bottles that take no more than three months to get from the harvest to the shelf are your best choice, and the farther away the best-by date is from when you buy the oil, the fresher the product will be, Kyriakides said.

The International Olive Council has recommended brands limit the best-by date to no longer than two years after bottling.

If a brand’s bottle says the harvest season was “23/24,” for example, “that means their harvest lasted the latter part of 2023 into early 2024,” Kyriakides said. “Others will be very strict — they will say October, September 2023.”

For fans in the United States, getting fresh olive oil doesn’t mean it needs to be imported anymore. It’s been made possible by the growth in US-based producers — especially in California, where there’s a climate conducive to growing native varieties of olive trees and locals can get high quality oil within a much shorter time frame. Georgia, Oregon, Texas and Arizona also produce olive oil, but on a smaller scale.

Just like the compounds in tea or chocolate, those in olive oil degrade with time, especially if it’s stored in a hot environment or exposed to light or air, said Dr. Selina Wang, an associate professor of cooperative extension in small-scale fruit and vegetable processing at the University of California, Davis.

This is why storing the oil in a cool environment and a dark-colored glass bottle throughout the olive oil’s life is crucial. The importance of a cool environment is also why consuming the oil raw, say as a salad dressing, is better than using it to cook. But regardless of how it is consumed, olive oil is much healthier than heavily refined oils purchased at the grocery store, experts said.

If at the grocery store you see extra virgin olive oil stored on a top shelf near bright, big lights and the bottle is warm, that’s a red flag, Kyriakides said.

“I’m not going to buy that oil, because I know it’s been sitting there, it’s been exposed to that heat already,” he added.

Preserving your oil at home

Besides information on harvest and processing dates, another way to gauge the freshness of your oil is by taste.

“The more taste an olive oil has, the more health benefits,” as the compounds responsible for them also contribute to the oil’s taste, said Joseph R. Profaci, executive director of the North American Olive Oil Association, an industry trade association, via email. “If health is the primary driver, the consumers should look for those that are robust rather than mild.”

For that reason, Profaci urged that people “get accustomed to cracking open their olive oil bottle as soon as they get it home and tasting it,” he added. “That will help them develop a more discerning palate for olive oil. If they take that taste and are disappointed, and especially if it has the rancid taste of wax crayons or stale nuts, take it back to the store and ask for a refund or replacement.”

And once you taste it, if the oil’s fresh enough, don’t put it on the back burner for special occasions, Wang said.

“You should consume your olive oil as soon as possible,” she added, “because the reasons that you purchase it — which is for the health and then the flavor — those both decline as the oil ages.”  

Consistently keeping the oil in the fridge can extend the protection of the phenolics for another year or two — just be sure to set it on the counter a little in advance of putting it on your salad so it can warm up to its normal consistency, Kyriakides said.

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