Study shows EVOO improves endothelial function and heart health

In a promising finding for heart disease prevention, new research conducted by the Yale-Griffin Prevention Research Center has found that the consumption of extra virgin olive oil improves endothelial function, a marker of heart health. Endothelial function is a measure of overall blood vessel elasticity, and how well blood vessels expand as blood flows through, and is considered an independent predictor for risk of future cardiovascular events.

Significantly, no such benefit was found for refined olive oil.

The research

In the study, recently published in The International Journal of Cardiology, the researchers compared the effects of consuming high polyphenol extra virgin olive oil and refined olive oil respectively on measures of cardiovascular health in adults with prediabetes.

The problem

According to Diabetes Australia, an estimated 1.2 million Australians have a diagnosis of diabetes, and another two million have pre-diabetes. People with diabetes or at risk of diabetes are more likely to develop other chronic health problems such as cardiovascular disease, stroke, and hypertension, and have a higher risk of dying prematurely.

Method

The study involved a randomized, controlled, double-blind, crossover trial of 20 adults (mean age 56.1 years; 10 women, 10 men) at risk for type 2 diabetes.

Each participant was assigned two intervention treatments, consisting of either 50 mL of high-polyphenolic EVOO or 50 mL of refined olive oil without polyphenols, with a one-week washout in between. The olive oils were consumed in a smoothie consisting of ½ cup frozen blueberries and 1 cup (8 oz) low-fat vanilla yogurt blended together.

The primary outcome measure was endothelial function (EF) measured as flow-mediated dilatation. Participants were evaluated before and two hours after ingestion of their assigned olive oil treatment.

Results

The study team found that a single 50 mL dose (about 2 ½ tablespoons) of EVOO, taken as above, led to improved endothelial function two hours after ingestion. There was no improvement from the refined oil. No short-term effect on blood pressure was found with either type of olive oil.

The principal investigator of the study said that the difference between the olive oils was statistically and clinically significant.

“While research over the past few years has shown that olive oil can offer considerable benefits to heart health, results of those studies have not always been consistent,” said Dr Valentine Njike, MD, MPH.

“This may be due to the fact that the nutritional content of olive oil varies. For example, all olive oils are relatively high in monounsaturated fat, which is thought to be ‘heart-healthy’, but extra virgin olive oil contains higher levels of biophenols. These natural compounds modulate oxidative stress and are thought to slow the progression of cardiovascular disease.”

Dr Njike emphasised the need for a larger study with a longer time frame to add to the findings of this study, as well as studies to help clarify how extra virgin olive oil influences cardiovascular health.

Source: Post-prandial Effects of Highpolyphenolic Extra Virgin Olive Oil on Endothelial Function in Adults at Risk for Type 2 Diabetes: A Randomized Controlled Crossover Trial: Valentine Y. Njike, Rockiy Ayettey, Judith A. Treu, Kimberly N. Doughty, David L. Katz. DOI:https:// doi.org/10.1016/j.ijcard.2021.01.062 - www. internationaljournalofcardiology.com.

Note: The study was funded by Cobram Estate, and supported by the Centre for Disease Control and Prevention (CDC).