Olive Polyphenols: Findings on Blood Sugar, Blood Pressure and Triglycerides

A new randomized clinical trial suggests that the value of olives may extend well beyond their healthy fat.

Olive oil is widely recognized as one of the defining foods of the Mediterranean diet. Most discussions of its health benefits focus on its monounsaturated fat—particularly oleic acid.

But olives also contain naturally occurring compounds called polyphenols. Although present in relatively small amounts, these bioactive compounds are attracting scientific attention for their antioxidant and anti-inflammatory properties.

A randomized clinical trial published in the February 2026 issue of Clinical Nutrition ESPEN examined whether a concentrated olive oil polyphenol supplement could affect several important markers of metabolic health.[1]

What Are Olive Polyphenols?

Polyphenols are compounds produced naturally by plants, where they help protect against environmental stress. Olives contain a distinctive family of polyphenols, including oleocanthal, oleacein, oleuropein derivatives, hydroxytyrosol and verbascoside.

The amounts and types present vary depending on the olive variety, growing conditions, ripeness, processing and storage. Different olive extracts can therefore have very different polyphenol profiles.

In humans, olive polyphenols have been studied for their potential effects on oxidative stress, inflammation, blood-vessel function and metabolic health.

Olive Fruit Extract Is Not the Same as Olive Leaf Extract

Many olive supplements use olive leaf extract. Olive leaves are plentiful, relatively inexpensive and naturally rich in oleuropein, making them an economical source of concentrated polyphenols.[2]

But an olive leaf is not an olive fruit, and their polyphenol profiles are not interchangeable. Most olive leaf extracts are standardized primarily for oleuropein, the dominant polyphenol in the leaf. Olive fruit provides a different spectrum of polyphenols that changes as the fruit ripens.

This distinction is important to Olivino® Essential. Rather than using a conventional olive leaf extract, Olivino contains Opextan®, a premium food-grade extract made from the pulp of Coratina olives.

Native to Puglia in southern Italy, Coratina is a highly prized olive varietal known for its robust character and naturally rich polyphenol profile. Opextan is standardized for total polyphenols and distinguished by its concentration of verbascoside, together with hydroxytyrosol and other olive-fruit polyphenols.[3]

We chose Opextan because its fruit origin and distinctive polyphenol profile authentically complement the grape- and tomato-derived bioactives in Olivino.

What the Researchers Studied

The OleoMetS clinical trial included 102 adults with metabolic syndrome.

Metabolic syndrome is not a single disease. It refers to a cluster of interconnected risk factors that can include elevated blood sugar, high blood pressure, abnormal triglyceride or cholesterol levels, excess abdominal weight and insulin resistance. Together, these conditions increase the risk of cardiovascular disease and type 2 diabetes.

In this double-blind, randomized, placebo-controlled trial, participants received either:

• 10 mg per day of a concentrated olive oil polyphenol extract
• A matching placebo

The intervention lasted for 12 weeks. Participants were not instructed to change their diet or physical activity, and all 102 completed the trial.

The extract was composed primarily of oleocanthal and oleacein, along with smaller amounts of oleuropein and ligstroside derivatives. Fasting blood glucose and hemoglobin A1c were the study’s primary outcomes.

What the Researchers Found

Compared with the placebo group, participants receiving the olive polyphenol supplement experienced significant improvements in several metabolic measurements.

Blood Sugar

Fasting blood glucose decreased by an average of 7.06 mg/dL compared with placebo.

Hemoglobin A1c decreased by 0.29 percentage points. Often abbreviated as HbA1c, this measurement reflects average blood sugar levels over approximately the previous two to three months.

Together, the changes suggest improvements in both shorter- and longer-term measures of glucose regulation.

Blood Pressure

Systolic blood pressure—the top number in a blood-pressure reading—decreased by an average of 7.66 mmHg compared with placebo.

Blood pressure was a secondary outcome, so this finding should be interpreted more cautiously than the prespecified blood-glucose results. Nevertheless, it is noteworthy given the relationship between metabolic health, blood pressure and cardiovascular risk.

Other Metabolic Markers

The researchers also reported reductions in:

• Triglycerides
• Oxidized LDL
• Body mass index
• Uric acid
• A liver enzyme called ALT
• Self-reported fatigue

Oxidized LDL forms when LDL particles are altered by oxidative stress. It is considered more damaging to blood vessels than unmodified LDL and is involved in processes associated with atherosclerosis.

The supplement was well tolerated, with no serious adverse events reported.

Why These Findings Matter

The study helps distinguish between two important components of olives.

The first is oleic acid, the predominant monounsaturated fat in olive oil. Replacing saturated fats with unsaturated fats is an established part of a heart-healthy dietary pattern.

The second is the much smaller polyphenol fraction. These compounds may affect health through different pathways, including antioxidant defense, inflammatory signaling and cellular metabolism.

Because the researchers administered concentrated polyphenols in capsule form, the trial offers evidence that the polyphenol fraction may have biological activity apart from olive oil’s fat.

This does not diminish the importance of extra-virgin olive oil or the broader Mediterranean diet. Instead, it helps explain why olives may offer more than a favorable fatty-acid profile.

An Important Qualification

The findings are promising, but they require perspective. The study lasted only 12 weeks and involved 102 people with metabolic syndrome. It did not determine whether the improvements would persist or ultimately result in fewer heart attacks, strokes or cases of diabetes.

Several findings—including blood pressure, triglycerides and oxidized LDL—were secondary outcomes and should be confirmed in larger, longer clinical trials. The study tested one specific olive oil polyphenol extract; it did not test Opextan or Olivino Essential. Because olive extracts differ in composition, the results cannot be attributed directly to another ingredient or finished product.

Where Olivino® Essential Fits

Although the OleoMetS trial did not test Olivino, it reinforces the scientific rationale behind its formulation: olives provide bioactive polyphenols in addition to healthy fat.

Olivino Essential uses Opextan because it is a standardized extract from Coratina olive fruit rather than an inexpensive generic leaf extract. Its fruit-derived polyphenols, including verbascoside, complement clinically researched bioactives from grapes and tomatoes as part of the Fruits of the Mediterranean Diet®.

Each daily serving of Olivino Essential provides 160 mg of Opextan, standardized to contain at least 10% total polyphenols—equivalent to at least 16 mg of olive-fruit polyphenols. For context, the OleoMetS trial administered 10 mg per day of olive oil polyphenols. This is an informative numerical comparison, but it is not a dose-equivalence claim: the clinical trial used an extract composed primarily of oleocanthal and oleacein, whereas Opextan provides a different fruit-derived polyphenol profile characterized by verbascoside and hydroxytyrosol derivatives. Consequently, the clinical findings cannot be attributed directly to Opextan or Olivino Essential.

Olivino was designed to complement—not replace—a healthy Mediterranean diet. The takeaway is to appreciate olives more fully: as a source of healthy fat, distinctive polyphenols and one of the many plant foods that make the Mediterranean dietary pattern so compelling.

To your good health!

References

1. Samoutis G, Kyriakides TC, Demetriou N, et al. The impact of olive oil polyphenol supplementation on metabolic syndrome parameters: The OleoMetS study, a randomized, controlled clinical trial. Clinical Nutrition ESPEN. 2026;71:102883. https://doi.org/10.1016/j.clnesp.2025.102883

2. Munekata PES, Alcántara C, Collado MC, et al. Phenolic compounds obtained from Olea europaea by-products and their use to improve the quality and shelf life of meat and meat products—A review. Antioxidants. 2020;9(11):1061. https://doi.org/10.3390/antiox9111061

3. Indena. Opextan® olive fruit extract. https://www.indena.com/product/opextan/

 

About the Author
Clare Hasler-Lewis, M.S., Ph.D., MBA, is CEO and Co-Founder of OlivinoLife, Inc., and a nutrition scientist who has spent more than 35 years translating nutrition research into practical health information. She is the author of the Med Diet News series, which explores the latest science on the Mediterranean diet and healthy aging.