Updated: Feb 2, 2021
The health benefits of Omega-6’s Monounsaturated fats (MUFA’s) contained in olive oil has been well studied. Especially, MUFA's contained in the Mediterranean Diet. However, researchers interested in continual study on specific populations, continue to garner more and emerging information.
Assertions of it's many benefits include helping to boost heart health by preventing adverse health issues, that lead to cardiovascular disease or stroke. Unrefined Extra Virgin Olive Oil (EVOO), has shown to achieve these health benefits because of its anti-inflammatory properties, which help lessen cell damage that can lead to heart disease and certain cancers.
Concerns between cold and hot consumption and adverse effects from exceeding EVOO smoking point during the cooking process have been brought up; since the cooking process, may degrade the beneficial antioxidants that give EVOO its anti-inflammatory properties. Researchers found that EVOO was one of the more heat stable oils. Therefore, based on those findings there are no significant concerns about heated EVOO and antioxidant integrity. A discussion about smoking point will be discussed further in the blog.
Recommendations for supplementation are incorporating 2 to 4 tablespoons of olive oil into the diet, a day, and should be sourced from whole foods such as fish, nuts, and particularly EVOO, since EVOO is the least refined form of olive oil. Recommendations for EVOO consumption, as fuel, for its satiating and high caloric affects has shown to be beneficial for training purposes.
Significant claims about the potential impact between EVOO consumption and favorable heart health and anti-inflammatory benefits particularly for high intense athletes. Concerns around recommendations and dosage, without consultation, absent of nutritional guidance and counseling, for average individuals or other special populations are significant. Without direct study on specific populations, recommendations cannot be made in good faith.
A particular study concerning the benefits of the Mediterranean Diet, which emphasizes fat consumption from EVOO, fresh vegetables, fruits, legumes, whole grains, fatty fish, lean meats, and dairy in moderation were covered in a comprehensive study conducted in Spain on Coronary Heart Disease (CHD) patients. The study directly explored the effects of EVOO consumption contained in the Mediterranean Diet on endothelial function, provides compelling evidence.
The study was called CORonary Diet Intervention with Olive oil and cardiovascular PREVention (CORDIOPREV) study. The study was an ongoing prospective, randomized, single-blind, controlled trial of 1,002 cohort (805 after randomization) Coronary Heart Disease (CHD) patients, with 6 months after a coronary event. It evaluated the efficacy of a Mediterranean diet, rich in Monounsaturated fatty acids (MUFA’s) from olive oil, as compared to a Low-Fat diet to prevent clinical events and mortality in patients with previous CHD in a long-term follow-up study. The study measured endothelial function through Flow-Mediated Dilation (FMD) in the brachial artery through ultrasound. Flow-Mediated Dilation test is a noninvasive test that utilizes ultrasound measure of the changes in the diameter of an artery.  The measurement of dilation in the artery provides the level, ease, and rate of blood flow, through the artery. Endothelial Function was measured at baseline. Based on this data, three separate groups of endothelial function emerged, less severe, moderate severe, and severe; to provide a clear delineation, the moderate group was eliminated.
For ‘in vitro’ evaluation of blood serums from CHD patients were also studied for biochemical markers. Cell Cultures of Endothelial progenitor cells (EPC) were evaluated for damage by viewing levels of Reactive Oxygen Species (ROS), Apoptosis, and Senescence. This data provided the level of inflammation due to cell damage. For comparison, EPC cells were also evaluated for rate of repair through Cell Proliferation, Angiogenesis, and Other Modulators. Human Umbilical Vein Endothelial Cells and Human Coronary Artery Endothelial Cells from healthy individuals were used as controls. These values provided healthy cells baseline values. The study design was a randomly stratified study. A baseline diet was taken through an intake process. The length of study was 1 year. The criteria of the study included both Male and Females, with a wide age range from 20-75 years old. Other study subject criteria included, no other serious illnesses, a life expectancy of at least 5 years, and a history of a previous Myocardial Infarction, about 6 months prior to the start of the study.
Researchers found ‘in vivo’, higher HDL Cholesterol levels and lower fasting glucose levels in the Mediterranean Diet Group. They also discovered increases of FMD dilation after consumption of the Mediterranean Diet and no effect on the Low-Fat Diet Group, regardless of severity of endothelial dysfunction.
Those in the Mediterranean Diet increased EPC levels and lowered EMP levels and improved EMP/EPC ratio in both endothelial dysfunction groups (low and severe). For those, in the Low-Fat Group a slight increase in EPC concentration for patients with low endothelial dysfunction. But those with severe endothelial dysfunction showed an increase in EMP/EPC ratio but did not show any effect on EPC levels.
Specific approaches that researchers found ‘in vitro’ by vascular endothelial homeostasis included cellular processes related to endothelial damage. They found that serum for patients on the Low-Fat Diet increased intracellular ROS production, cellular apoptosis, and increased cellular senescence regardless of endothelial dysfunction. However, serum of patients on the Mediterranean Diet showed lower intracellular ROS production, cellular apoptosis, and decreases in cellular senescence regardless of endothelial dysfunction. Cellular Regenerative Capacity serum of patients on the Mediterranean Diet showed increases in cellular proliferation and angiogenesis, while no changes, in cellular proliferation and angiogenesis in the Low-Fat Diet population. This data suggests that the Mediterranean Diet, high in EVOO consumption, are effective at modulating inflammation that may lead to cell damage and increases protective measures through assisting repair from minimal cell damage. It also suggests that modulation is effective on both severely impaired and less impaired endothelial blood vessel function.
Some limitations of the study includes that it was conducted in Spain. Since Spain is in the Mediterranean area, an environmental determinant, may increase cultural behavior adherence since elements of cultural eating practices may already be similar to the Mediterranean diet. There would be less of a barrier to dietary compliance. It may not be ideal for implementing worldwide or other geographical or cultural barriers may exist. In addition, the study was conducted on a cohort of CHD patients and may not be conducive for other individual populations and countries. The study was well constructed and studied, but other lifestyle factors related to Spain may contribute to overall health outcomes; such as, ample exposure to sunny weather (Vitamin D levels), socio-economic factors, level of support, access to nutritious food, and socialized healthcare.
The study had many strengths such as being an ongoing prospective, randomized, single-blind, controlled trial study. It was well-constructed with several different baseline values, different data analysis, and different testing methods, which included in vivo and in vitro study designs. These study designs included testing methods that used cell analysis and physical diagnostics. The study had a large and diverse sample size of 805 individuals, male and female subjects, a wide age-range, along with values from two severity levels of endothelial dysfunction. It also had a significant study period lasting 6 months. The strengths of the study provides information to create viable dietary interventions related to use as clinical and therapeutic tools to address CHD.
In conclusion, data acquired from this study suggests that the Mediterranean Diet, high in EVOO consumption, compared to a Low-Fat Diet may improve endothelial dysfunction in CHD patients; by balancing vascular endothelial homeostasis in both patient groups with low and severe endothelial dysfunction. The information provided by the study was compelling evidence about the efficacy of the Mediterranean Diet, which utilizes EVOO oil, compared to Low-Fat Diet on endothelial function in CHD patients. But dietary recommendations and interventions based on this study, would not be fully appropriate in other cohort populations, like healthy athletes or generalized populations, without further specific studies on those populations.
The information gathered from the study about improving HDL Cholesterol levels and lowering fasting glucose levels while increases of FMD in the Mediterranean Diet Group, that utilizes EVOO, is data that can be significant in other populations aside from CHD patients. Therefore, my final analysis is that if the question is whether Olive oil is beneficial, the answer according to this study, suggests that the response is both compelling and confirmative.
References:  Serrano-Yunberro et al. Mediterranean diet and endothelial function in patients with coronary heart disease: An analysis of the CORDIOPERV randomized controlled trial. PLoS Med. 2020, 17(9): 1-28.