The Polyphenol Race: Inside Olive Oil’s Numbers Game

As consumers become more educated about extra virgin olive oil’s health benefits, one metric has become a growing obsession across the industry: polyphenol content.

From Greece to Peru, producers are prominently displaying laboratory results on labels, websites and social media. Some brands are marketing oils containing anywhere from 500 to more than 2,000 milligrams per kilogram (mg/kg) of phenolic compounds.

There’s very little evidence to say that we should be absolutely maxing out on polyphenols.– Simon Poole, Physician, author and consultant

The European Union allows producers to state that polyphenols contribute to the protection of blood lipids from oxidative stress when their olive oil has at least five milligrams of hydroxytyrosol and its derivatives, such as oleuropein complex and tyrosol, per 20 grams of olive oil — or 250 mg/kg.

Many producers see polyphenol counts as a direct measure of their oils’ quality bona fides. But some in the industry worry that a race to increase polyphenol content at all costs is underway, fueled by a lack of consensus on what constitutes a high-polyphenol extra virgin olive oil.

“The 250 mg/kg mark is the minimum you need to qualify for the E.U. health claim, but I would not consider that as high polyphenol,” said award-winning producer Arsen Khachaturyants of Arsenio in Italy.

Instead, he sees this as the baseline for defining high-polyphenol olive oil. In his view, 400 or 500 mg/kg qualifies an extra virgin olive oil as “high-polyphenol.” Others say the baseline should be significantly higher.

At the extreme end of the spectrum, one Slovenian producer has already reached 1,500 mg/kg and has set a goal of 5,000 mg/kg. Khachaturyants, for his part, argued that 900 mg/kg is already too high.

Another complication: polyphenol content can vary depending on the laboratory method used to measure it, making comparisons between oils from different producers less straightforward than the numbers alone suggest. Some in the field point to inconsistent testing standards as part of the problem.

Medical experts, meanwhile, say there is little evidence that ever-higher polyphenol intake produces proportionally greater health benefits.

According to Mary Flynn, an associate professor of medicine at Brown University, polyphenols are responsible for the majority of extra virgin olive oil’s health benefits. She estimates that beneficial effects on blood lipid markers begin to appear at around 150 mg/kg.

“There’s very little evidence to say that we should be absolutely maxing out on polyphenols,” said Simon Poole, a medical doctor, author and health consultant. “We should have good-quality, great-tasting, enjoyable extra virgin olive oil as a food, which will inevitably provide us with those doses of polyphenols through the day.”

Amy Riolo, an award-winning chef and author, said many high-polyphenol extra virgin olive oils are unbalanced and therefore do not pair well with many dishes.

“Anything above 800 mg/kg is very high,” she said. “Basically, those olive oils belong to a health food, almost medicinal category, versus a kitchen ingredient category.”

Khachaturyants believes producers need to find a balance between maximizing polyphenol content and preserving organoleptic quality. “At the end of the day, olive oil is not medicine,” he said.

Other award-winning producers, including Bianti Danaj of Donika Olive Oil in Albania, believe high-polyphenol olive oils can still be pleasant to eat. He said his company has won gold awards at the NYIOOC World Olive Oil Competition with polyphenol levels at 800 mg/kg.

“If you look at the list of NYIOOC winners, it’s very rare for an olive oil in the 800 mg/kg range to win a medal, because oils with such high polyphenol content are usually very bitter or not especially pleasant to drink,” Danaj said. “We’re very happy that we were able to achieve a very high-phenol olive oil while also receiving recognition for its taste, aroma, bitterness and pepperiness.”

Danaj and others say high-polyphenol extra virgin olive oils have found a niche in the kitchen rather than the medicine cabinet.

Still, a growing segment of the industry markets the product as a health supplement rather than as a food.

Some producers are packaging high-polyphenol olive oils, some exceeding 1,500 mg/kg, in capsules or small vials for sale in pharmacies. Others are working with, or even building their own, laboratories to extract phenolic compounds from olive oil and olive pomace to sell separately.

Poole and Khachaturyants both warned that more research is needed into the impact of such high polyphenol doses. Poole said the history of antioxidant supplementation shows why assuming “more is better” can be risky.

In the early 1990s, some epidemiological studies suggested that high doses of vitamin E and vitamin A — both antioxidants, as are polyphenols — could reduce cancer risk.

A later longitudinal study, however, found no reduction in lung cancer incidence among male smokers after five to eight years of dietary supplementation with high daily doses of the two vitamins. “In fact, this trial raises the possibility that these supplements may actually have harmful as well as beneficial effects,” the researchers wrote.

Others argue that the focus on maximizing polyphenol content often overlooks the impact of post-production storage and transportation on phenol levels, as well as which phenols are actually being measured.

Indeed, a frequently cited problem with labeling bottles by polyphenol content is how storage conditions — including temperature, light exposure and time — degrade them on the way from producer to consumer.

Khachaturyants countered that polyphenol content should be treated as an additional criterion available to consumers choosing the best extra virgin olive oil for their needs.

“People more or less understand what polyphenols are,” he said. “They understand that they’re beneficial. So I think it’s time for a producer to start putting that information on the back label.”

Leandro Ravetti, co-chief executive of award-winning Australian-American producer Cobram Estate, warned that the term “polyphenols” is an umbrella term, ranging from compounds associated with olive oil’s health benefits to others that are far less impactful.

“Many phenols do not always equal better olive oil; it’d be like saying that more tannins make better wine,” he told Pablo Voitzuk for the latter’s forthcoming book, The Olive Is Innocent.

Ravetti recalled an experiment he ran in northern Argentina in which all of his harvesting and milling decisions were made to maximize the phenolic content of an Arbequina monovarietal.

“I managed to do it, but the oil tasted like water with pepper,” he said. “It was not desirable.”

While Ravetti said phenolic compounds are essential to both the health benefits and shelf life of extra virgin olive oil, he urged producers to think carefully about phenolic composition, not just quantity.

“A large number of phenols does not mean quality per se. Which phenols? From which variety?” he told Voitzuk. “Having a good phenol count from a Coratina that offers such a complex profile of phenols, or from a variety subject to hydric stress, is not the same. It can peak in its ligstroside phenols, rendering an olive oil too astringent. That’s why we need to know the source of those phenols. And harmony is essential, too.”