Written By Janie Delport

Olive oil polyphenols & cardiovascular health (2/3)

As outlined in the previous blog about polyphenols and cardiovascular health, strokes among people under 50 in the Netherlands have increased by 50% over the past decade. The good news: up to 80% of these strokes are preventable through a healthy diet and regular physical activity. Neurologists frequently recommend the Mediterranean diet. Extra virgin olive oil is the main fat source of this diet. It is, however, not just the mono-unsaturated fats, but the polyphenols (such as such as hydroxytyrosol, oleuropein and oleocanthal) in extra virgin olive oil that protect your cardiovascular health. For this benefit, you need to consume high-polyphenol extra virgin olive oil with more than 250 mg/kg hydroxytyrosol.

Drawing on a 2025 Wageningen University & Research report, the previous blog on polyphenols and cardiovascular health outlines that polyphenols prevent the oxidation of LDL cholesterol (“bad” cholesterol), a process that leads to artery-clogging atherosclerosis. Numerous peer-reviewed studies and reviews confirm that consuming high-polyphenol olive oil, and specifically olive oil rich in hydroxytyrosol, significantly reduces oxidized LDL.

In this blog, we will dive in two other ways olive oil polyphenols protect your cardiovascular health. The second way is that polyphenols reduce inflammation in your arteries.

Chronic low-grade inflammation plays a key role in heart disease, because it damages artery walls and accelerates atherosclerosis. Let me explain this to you in more simple terms. Imagine that your body has a fire alarm system. When your body gets attacked by an infection, the alarm system starts working and sets off a little "fire" called “inflammation”. This inflammation helps protect your body and heal the infection. It is totally normal and helpful, but becomes harmful when your body keeps that fire alarm on, even when there is no infection. This creates a small, constant fire inside your body, which is not big enough to notice, but just enough to slowly cause problems. That is called chronic low-grade inflammation.

Low-grade inflammation is caused by eating ultra-processed food (like sugary snacks, fried food or soda). This low-grade inflammation damages the inside of your arteries, where your blood flows. Over time, this makes it easier for bad cholesterol (LDL) to stick to the artery walls, causing clogging (atherosclerosis). That is how low-grade inflammation leads to heart disease, heart attacks, or strokes.

Scientific studies consistently demonstrate that olive oil polyphenols, and especially a specific olive oil polyphenol called oleocanthal, reduce low-grade inflammations that lead to atherosclerosis (Correia, M., et al, 2025; Widmer et al., 2013; Sarapis et al., 2022; Castañer et al., 2012; Medina-Remón et al., 2017; Camargo et al., 2010; Konstantinidou et al., 2010). In fact, the literature study executed by Wageningen University & Research in 2025, found several big studies and large reviews that all showed that polyphenols in olive oil reduce inflammation in your arteries:

  • The study of Medina-Remón et al., 2017 studied over 1,100 healthy people and found that those who consumed more olive oil polyphenols for 1 year had much lower levels of harmful inflammation in their blood vessels.

  • In the study of Castañer et al., 2012, healthy people tried different olive oils with low, medium, and high amounts of polyphenols. After 3 weeks, the people who used the olive oil with the most polyphenols had fewer signs of inflammation in their blood.

  • In the study of Camargo et al., 2010, people with a condition called metabolic syndrome (which makes it easier to get heart disease) ate breakfasts with either low or high-polyphenol olive oil. The high-polyphenol group showed changes in their genes that made their bodies better at fighting inflammation.

  • In the study of Konstantinidou et al., 2010, 3 groups of people were analysed: one group ate a Mediterranean diet with high-polyphenol olive oil, another group ate the same diet with low-polyphenol oil, and a third group just ate their usual food. After 3 months, the high-polyphenol group (the first group) had the biggest drop in inflammation-related markers in their blood.

  • In the study of Beauchamp et al., 2005, people who ate 50 grams of extra virgin olive oil with a high amount of oleocanthal (about 9 mg) showed a drop in the enzymes that cause inflammation, similar to how ibuprofen works.

Even when scientists combined the results of 30 different human trials (Tsartsou et al., 2019), they found the same pattern: olive oil rich in polyphenols consistently reduces inflammation in the blood vessels. Especially the polyphenol Oleocanthal helps "cool down" inflammation in your body like a natural fire extinguisher. The biggest effect on the reduction of chronic low-grade inflammation can be seen when people daily consume extra virgin olive oil with more than 180 mg/kg oleocanthal. The olive oils from the Olive Oil Club contain even more oleocanthal, starting at 213 mg/kg. This means you can reduce harmful low-grade inflammation just by adding those olive oils to your diet.

The third way polyphenols in extra virgin olive oil protect your cardiovascular health is that polyphenols improve your cholesterol profile. Olive oil polyphenols improve your cholesterol balance, also called your lipid profile or cholesterol profile. When doctors talk about cholesterol balance, they mean having enough of the good kind (HDL) and not too much of the bad kind (LDL). A healthy balance helps keep your blood vessels clean and your heart strong. Additionally, HDL has a role in clearing out LDL from your blood vessels. If this balance is off, because you have, for example, too much LDL or too little HDL, it raises your risk of cardiovascular diseases. Neurologists consider cholesterol balance one of the key indicators for assessing a patient's risk of having a stroke. The good news is that olive oil polyphenols help keeping your cholesterol balance in check. This claim is supported by many scientific studies:

  • In the study of Covas et al., 2006, scientists gave 200 people olive oils with different amounts of polyphenols. The more polyphenols the olive oil had, the better their cholesterol ratio (HDL/LDL) became.

  • In the study of Hernáez et al., 2014, high-polyphenol olive oil made the HDL (good cholesterol) better at clearing out LDL (bad cholesterol) from blood vessels. It even made the HDL particles larger and more flexible, making them even better at their job.  

  • The study of Pedret et al., 2015, shows how olive oil polyphenols improved the protein makeup of HDL in 33 people with high cholesterol. These improvements ensured the HDL was better able to defend against oxidation and reduce inflammation in blood vessels. So, the study shows that polyphenols improve the quality and protective power of HDL, which enhances the balance between good and bad cholesterol.

  • In the study of Farràs et al., 2015, people’s HDL improved in terms of structure and function, meaning it could protect cells better after consuming polyphenol-rich olive oil.

Findings from two meta-analyses and one systematic review reinforced these outcomes. When scientists reviewed many of these studies together, they found the same thing: high-polyphenol olive oil helps raise HDL, lower LDL, and makes your cholesterol balance healthier overall (Zupo et al., 2023; George et al., 2019). The researches suggest that the amount of polyphenols in olive oil matters a lot when it comes to improving cholesterol balance. The study of Covas et al. (2006) with 200 people showed that the more olive oil polyphenols people consume, the higher the HDL and the lower the LDL. Therefore, it is recommended to consume extra virgin olive oil with a total polyphenol count of  over 350 mg/kg. The olive oils from the Olive Oil Club contain much higher total polyphenol levels (starting at 699 mg/kg and reaching 1857 mg/kg), implying that these olive oils support your cholesterol balance.

[The next blog post will provide you with the last two ways polyphenols in extra virgin olive oil protect your cardiovascular health.]

References:

Beauchamp, G. K., Keast, R. S. J., Morel, D., Lin, J., Pika, J., & Breslin, P. A. S. (2005). Ibuprofen-like activity in extra-virgin olive oil. Nature, 437(7055), 45–46.

Castañer, O., Covas, M. I., Khymenets, O., Nyyssönen, K., Zunft, H.-J. F., de la Torre, R., ... & Fitó, M. (2012). Protection of LDL from oxidation by olive oil polyphenols is associated with a downregulation of CD40-ligand gene expression and its downstream products in vivo in humans. The American Journal of Clinical Nutrition, 95(6), 1238–1244.

Camargo, A., Ruano, J., Fernandez, J. M., Parnell, L. D., Jimenez, A., Sánchez, A., ... & Perez-Martinez, P. (2010). Gene expression changes in mononuclear cells in patients with metabolic syndrome after acute intake of phenol-rich virgin olive oil. BMC Genomics, 11, 253.

Correia, M., et al. (2025). Effects of oleocanthal-rich extra virgin olive oil on low-grade inflammation: A randomized controlled trial.

Covas, M. I., Nyyssönen, K., Poulsen, H. E., Kaikkonen, J., Zunft, H.-J. F., Kiesewetter, H., ... & EUROLIVE Study Group. (2006). The effect of polyphenols in olive oil on heart disease risk factors: a randomized trial. Annals of Internal Medicine, 145(5), 333–341.

Farràs, M., Castañer, O., Martín-Peláez, S., Hernáez, Á., Schröder, H., Subirana, I., ... & Fitó, M. (2015). Polyphenol-rich olive oil improves HDL lipid composition and function in hypercholesterolemic subjects: A randomized controlled trial. Molecular Nutrition & Food Research, 59(8), 1548–1558.

George, E. S., Marshall, S., Mayr, H. L., Trakman, G. L., Tatucu-Babet, O. A., Lassemillante, A-C. M., ... & Tierney, A. C. (2019). The effect of high-polyphenol extra virgin olive oil on cardiovascular risk factors: A systematic review and meta-analysis. Critical Reviews in Food Science and Nutrition, 59(17), 2772–2795.

Hernáez, Á., Fernández-Castillejo, S., Farràs, M., Catalán, Ú., Subirana, I., Montes, R., ... & Fitó, M. (2014). Olive oil polyphenols improve the function of HDL in humans: The EUROLIVE study. Molecular Nutrition & Food Research, 58(12), 2368–2375.

Konstantinidou, V., Covas, M. I., Sarris, S., Salazar, G., Fitó, M., & Martinez-Gonzalez, M. A. (2010). In vivo nutrigenomic effects of virgin olive oil polyphenols within the frame of the Mediterranean diet: A randomized controlled trial. FASEB Journal, 24(7), 2546–2557.

Medina-Remón, A., Tresserra-Rimbau, A., Pons, A., Tur, J. A., Martorell, M., Ros, E., ... & Lamuela-Raventós, R. M. (2017). Polyphenol intake from a Mediterranean diet decreases inflammatory biomarkers related to atherosclerosis: A substudy of the PREDIMED trial. British Journal of Clinical Pharmacology, 83(1), 114–128.

Pedret, A., Covas, M. I., León, J., Fito, M., Valls, R. M., Cabré, M., ... & Solà, R. (2015). Molecular effects of olive oil polyphenols on HDL: A randomized controlled trial in humans. Atherosclerosis, 238(1), 45–51.

Sarapis, K., Georgoulia, P., Fasoulas, A., et al. (2022). High-polyphenol extra virgin olive oil reduces oxidized-LDL cholesterol and markers of inflammation: A randomized controlled trial. Nutrients, 14(12), 2546.

Tsartsou, E., Pratsinis, H., Koutsilieris, M., & Panagiotopoulou, H. (2019). Olive oil phenols and inflammation: A systematic review of in vivo studies. Critical Reviews in Food Science and Nutrition, 59(5), 746–760.

Widmer, R. J., Flammer, A. J., Lerman, L. O., & Lerman, A. (2013). The Mediterranean diet, its components, and cardiovascular disease. The American Journal of Medicine, 126(9), 779–786.

Zupo, R., Castellana, F., De Nucci, S., Sila, A., Gagliardi, G., Carreras, G., ... & Giannelli, G. (2023). Association between extra-virgin olive oil polyphenols consumption and improvements in lipid profile and cardiovascular risk: A meta-analysis. Nutrition Reviews, 81(3), 261–272.

Janie Delport
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