Fresh-Pressed Olive Oil Club
EVOO and Health

How EVOO Combats Heart Disease

Posted on by The Olive Oil Hunter

Part I: a Primer on Oleic Acid (OA)

A large body of evidence shows that daily consumption of EVOO confers numerous health benefits, including a significantly reduced risk of cardiovascular disease (CVD).

Factors that contribute to CVD include cholesterol, inflammation, blood vessel function, insulin resistance, and high blood pressure (hypertension). The protective effects of EVOO are attributed to its bioactive components, oleic acid (OA) and more than 30 polyphenols.

In this concise review, we’ll look closely at the mechanisms by which OA works in the body to modify and improve these factors.

What is OA? Oleic acid is a monounsaturated fatty acid (MUFA) that makes up approximately 70 to 80 percent of EVOO by volume. MUFAs and PUFAs (polyunsaturated fatty acids) are the key components of liquid fats, such as vegetable oils and the fats in fish.

Lowers “bad” cholesterol and blood lipid levels: OA lowers LDL or “bad” cholesterol by increasing the amount of LDL that is removed from the blood by the liver and reducing the amount that is produced. In scientific terms, OA increases hepatic LDL receptor activity. Similarly, OA helps lower triglyceride levels by stimulating the liver to increase the breakdown and removal of the proteins that produce triglycerides.

Helps regulate blood pressure: After eating, we experience what is termed the postprandial reflex—a rise in blood triglycerides and increase in blood pressure. When OA enters cell membranes, signals are sent from the intestines to the blood vessels to release vasodilators, which relax the blood vessels, and to block the release of vasoconstrictors, which tighten the blood vessels and raise blood pressure.

Protects the blood vessel lining: Damage to the blood vessel lining (the endothelium) is a major risk factor for CVD. By stimulating the release of vasodilators, OA helps protect the endothelium. OA
also blocks signals from inflammatory proteins that are released with the postprandial reflex, reducing oxidative stress (which can lead to cell damage) and helping prevent atherosclerosis (buildup of cholesterol plaques in the arteries).

Increases insulin sensitivity: In a study of patients with obesity, OA was shown to up-regulate—increase the activity of—a gene that increases insulin sensitivity. OA also reduces insulin resistance in vascular smooth muscle cells, which make up the blood vessel walls.

Studies continue to reveal the ways in which OA exerts its multiple health-promoting effects. In 2018, the FDA determined that evidence supported a qualified health claim that the daily consumption of 20g daily of high-OA oil (EVOO or other high-oleic oil) may reduce the risk of coronary heart disease.

Stay tuned for part II, in which we’ll explore how the polyphenols in EVOO exert powerful protective effects against CVD.

References: 1. Lu Y, Zhao J, Xin Q, et al. Food Science and Human Wellness. 2024;13:529-540. 2. Pirahanchi Y, Sinawe H, Dimri M. Biochemistry, LDL Cholesterol (National Library of Medicine, 2023). 3. Zheng C, Khoo C, Furtado J, Ikekawi K, Sacks FM. Am J Clin Nutr. 2008;88(2):279-281. 4. US Food and Drug Administration. Constituent Update, November 19, 2018. https://www.fda.gov/food/cfsan-constituent-updates/fda-completes-review-qualified-health-claim-petition-oleic-acid-and-risk-coronary-heart-disease.

Half a tablespoon of olive oil a day significantly lowered the risk of dementia-related death

Posted on by The Olive Oil Hunter

Reference: Tessier A-J, Cortese M, Yuan C, et al. Consumption of olive oil and dietary quality and risk of dementia-related death. JAMA Network Open. 2024;7(5):e2410021. doi:10.1001/jamanetworkopen.2024.10021.

A recently published analysis of two large, long-term studies found that consuming half a tablespoon or more of olive oil per day lowered the risk of dying of dementia by up to 34% in both women and men. The protective effect of olive oil consumption was even greater in women.

More than 92,000 participants from the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS) were included in this analysis. The NHS started in 1976 and enrolled 121,700 female registered nurses (ages 30–55). The HPFS began in 1986 as a similar study in men, enrolling 51,525 male healthcare professionals (ages 40–75).

Study participants responded every other year to detailed food frequency questionnaires (FFQ) about their consumption of specific foods. Questions about olive oil were added in 1990. Total olive oil intake was determined by three responses: olive oil used for salad dressings, olive oil added to food or bread, and olive oil used for baking or frying at home.

Olive oil intake frequency was categorized as follows:

• Never, or less than once per month
• Less than 4.5 grams (about one teaspoon) per day
• Between 4.5 and 7 grams per day
• More than 7 grams (about half a tablespoon) per day

About two-thirds of the study participants (65.6%) were women, about a third (34.4%) were men, and the average age at the start of the study was 56 years. Each participant’s FFQs from 1990 to 2014 (or for as long as the participant remained in the study) were totaled and averaged. Average olive oil intake was 1.3 grams per day in both studies.

Participants in the highest olive oil intake group—half a tablespoon or more of olive oil per day— reduced their risk of dying of dementia by 28% to 34%, compared to study participants who never or very rarely consumed olive oil. These results were regardless of other dietary habits and factored in socio-demographic and lifestyle differences.

Deaths due to dementia were confirmed by physician’s review of medical records, autopsy reports, or death certificates of study participants.

It has been proposed that consuming olive oil may lower the risk of dementia-related death by improving blood vessel health, yet the results of this analysis were not impacted by hypertension or high cholesterol in participants.

Limitations of this analysis include its predominantly non-Hispanic white population of healthcare professionals, which reduces the ability to generalize these results across more diverse populations. Also, the FFQs did not dis-tinguish among types of olive oil, which differ in their amounts of polyphenols and other bioactive compounds.

Phenols in EVOO are the primary source of its heart-health benefits

Posted on by The Olive Oil Hunter

Reference: Flynn MM, Tierney A, Itsiopoulos C. Is extra virgin olive oil the critical ingredient driving the health benefits of a Mediterranean diet? Nutrients. 2023;15:2915.

A recent scientific review, published in the journal Nutrients, provides strong evidence that the phenols in EVOO—which are not present in lower grades of olive oil—play a primary role in the heart-health benefits associated with olive oil and the Mediterranean diet. 

Phenols are bioactive compounds in plant-based foods. EVOO is rich in phenols, whereas refined olive oils are stripped of these health-promoting compounds by chemical production processes. 

Study Objectives

Dr. Mary Flynn, PhD, registered dietician, and associate professor of medicine at Brown University, identified 34 randomized, controlled trials published between 2000 and 2022 that evaluated the effects of EVOO on risk factors for heart disease: blood pressure, levels of LDL (“bad”) and HDL (“good”) cholesterol, blood sugar, and body weight. 

A main aim of the review was to isolate the effects of the phenols in EVOO from the potential effects of monounsaturated fatty acids (MUFAs), which are present in all grades of olive oil and other vegetable oils. Flynn hypothesized that the MUFA content is not responsible for the many health benefits of EVOO. 

Another objective was to identify a minimum daily amount of EVOO required to experience its health benefits and the timing for improvements in heart-health risk factors to be observed.

Findings

Across the 34 studies, EVOO improved multiple risk factors for heart disease as compared to other grades of olive oil, other plant oils, and low-fat diets: 

  • Lowered blood pressure
  • Lowered LDL and increased HDL
  • Improved insulin sensitivity
  • Proved effective in weight-loss diets and improved long-term weight management

Daily dose of EVOO

According to Flynn and colleagues, “Daily use of EVOO starting at approximately two tablespoons a day will improve a plethora of risk factors in as few as three weeks.”

Phenomenal phenols

It is the phenols in EVOO that confer its heart-health benefits, the authors concluded. In order to obtain optimal levels of phenols, they recommend consuming the freshest olive oil: “The phenol content of extra virgin olive oil is highest in olive oil made close to the harvesting of the olive and will decrease with age and storage. Thus, for maximum health benefits, the EVOO should be produced and consumed as close to harvesting the fruit as possible.” 

The authors noted some limitations of this review: most studies did not include the specific phenolic content of the EVOO used, and many were conducted in the EU, where EVOO has been a part of the diet for centuries. More investigation, especially studies that identify the specific levels of phenols, is needed to confirm and build on these findings. 

Dementia: Olive oil could help protect brain health, according to new study

Posted on by The Olive Oil Hunter

Adapted from the original research and an article by Robby Berman in Medical News Today, August 2, 2023

Consuming half a tablespoon of olive oil per day could substantially lower your risk of dying from dementia, a new study shows.

According to a presentation on July 24 at the NUTRITION 2023 conference in Boston, the study found that people who consumed half a tablespoon or more of olive oil daily had a 25% reduced risk of dying from dementia compared to people who did not consume olive oil.

What’s more, higher olive oil intake was linked to greater brain benefits. “We found a clear linear dose-response association between higher daily olive oil intake and lower risk of fatal dementia,” said presenter Anne-Julie Tessier, RD (registered dietician), PhD, a postdoctoral fellow at the Harvard T. H. Chan School of Public Health.

This US-based study is the first to investigate the relationship between diet and dementia-related death. The investigators analyzed the health records from 1990 to 2018 of more than 90,000 people in the US who did not have cardiovascular disease or cancer at the start of the study. During the study’s 28 years of follow-up, 4,749 participants died from dementia.

Replacing even a single teaspoon of margarine or commercial mayonnaise with olive oil was also associated with a 5-12% reduced risk of dying from dementia, according to the research team. These benefits were not seen with other vegetable oils.

The link between higher olive oil intake and lower risk of dying of dementia was observed regardless of the overall quality of people’s diets. This may indicate that components of olive oil provide unique benefits for brain health.

“Some antioxidant compounds in olive oil can cross the blood-brain barrier, potentially having a direct effect on the brain,” said Dr. Tessier. “It is also possible that olive oil has an indirect effect on brain health by benefiting cardiovascular health.” She noted that only a few individuals in the study consumed more than 15 mg (about 1 tablespoon) of olive oil daily.

A body of previous research has established an association between olive oil intake and a lower risk of heart disease, and incorporating olive oil as part of the Mediterranean diet has also been shown to help protect against cognitive decline.

Dr. Tessier reflected on the characteristics of olive oil that may confer its effects on the brain: “Olive oil may play a beneficial role in cognitive health through its rich content in monounsaturated fatty acids, which may promote neurogenesis [growth of brain cells]. It also contains vitamin E and polyphenols that have antioxidant activity.”

The research team advised that an observational study such as this is only able to identify an association and does not prove that olive oil is the cause of the reduced risk of dying from dementia. Randomized, controlled trials are needed to confirm the study’s findings and to help establish the optimal quantity of olive oil to consume in order to experience the most benefits.

Reference: Tessier JA, Yuan C, Cortese M, et al. Olive oil and fatal dementia risk in two large prospective US cohort studies. Poster presented at NUTRITION 2023 conference, Fairfax, VA, July 24, 2023.