Fresh-Pressed Olive Oil Club

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

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

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.

Olive oil is shown to improve brain health and memory in individuals with mild cognitive impairment

Adapted from an article by Matt Crouch, Auburn University (auburn.edu), March 6, 2023

Extra virgin olive oil may have positive effects on individuals with mild cognitive impairment, according to a recently completed study published in the journal Nutrients. The study’s findings suggest that compounds found in olive oil positively affect brain health and help improve the blood-brain barrier.

In the study, 25 adult participants experiencing mild cognitive impairment consumed 30 ml (about three tablespoons) of olive oil per day for six months. Thirteen of the participants consumed extra virgin olive oil (EVOO) and 12 consumed refined olive oil (ROO), as a control group. EVOO is rich in phenols, while ROO has been purified of phenols.

Study participants took several tests before and after consuming olive oil, including MRI scans, cognitive tests, and blood analysis to measure biomarkers related to Alzheimer’s disease.

This study evaluated the blood-brain barrier and its permeability—the degree to which it protects the brain. The blood-brain barrier, a network of blood vessels and tissue made up of closely spaced cells, plays a vital role in maintaining a healthy brain by protecting the brain from exposure to blood-related neurotoxins and in the clearance of brain waste products.

The study also measured levels of beta-amyloid and tau, two proteins associated with Alzheimer’s disease. In people with Alzheimer’s disease, levels of beta-amyloid and tau are increased.

The benefits of olive oil consumption were more pronounced in the EVOO group, but participants in the ROO group experienced improvements as well: Both EVOO and ROO improved cognitive function, as determined by the improved clinical dementia rating and other behavioral scores. Additionally, “our findings showed that EVOO and ROO altered two major biomarkers related to Alzheimer’s disease,” said Kaddoumi. “These alterations collectively could have played a role in improving the blood-brain barrier and improving function and memory.”

This study in individuals with mild cognitive impairment is the first to evaluate what happens to the human brain as a result of consuming olive oil.

“These results are exciting because they support the health benefits of olive oil against Alzheimer’s disease,” said Kaddoumi. “Based on the findings of this study and previous preclinical studies… we can conclude that adding olive oil to our diet could maintain a healthy brain and improve memory function.”

Reference: Kaddoumi A, Denney TS, Deshpande G et al. Extra-virgin olive oil enhances the blood-brain barrier function in mild cognitive impairment: a randomized controlled trial. Nutrients. 2023;14(23):5102. doi.org/10.3390/nu14235102.

Olive oil is beneficial for maternal-fetal health

Adapted from Cortez-Ribiero et al (2022) and an article by Liji Thomas, MD, in News Medical, January 3, 2023

Numerous studies have shown that olive oil can have positive effects on pregnancy.
A recent systematic review published in the journal Nutrition Research is the first to summarize the evidence for the protective effects of EVOO consumption on maternal-fetal health.

Introduction

Nutrition plays a vital role in the health of a pregnant woman and the outcome of her pregnancy. Olive oil is a healthy source of monounsaturated fatty acids (MUFAs) and phytochemicals such as polyphenols that promote favorable outcomes in pregnancy. In addition, olive oil is linked to lower rates of gestational diabetes mellitus (GDM), preeclampsia (a sudden, dangerous rise in blood pressure), and small-for-gestational-age (SGA) or large-for-gestational-age (LGA) infants.

A systematic review included nine studies from Europe, the UK, and Argentina, conducted between 2008 and 2020. Study sizes ranged from 30 to 35,000 women.

  • Six studies were interventional, including five randomized controlled trials, and three were observational (case-control or cohort studies).
  • Maternal-fetal outcomes evaluated included SGA, LGA, GDM, premature birth, preeclampsia, and cardiovascular risk.
  • The intervenional studies evaluated the effects of EVOO, while the observational studies did not specify the grade of olive oil.

What did this study show?

  • EVOO in particular, and olive oil in general, is associated with a reduction in the risk of maternal and fetal adverse effects, including GDM, SGA, LGA, prematurity, and preeclampsia.
  • EVOO supplementation was associated with favorable cardiovascular effects in pregnancy, including a decrease in triglyceride levels.

What are the implications?

  • SGA increases the risk of poor fetal outcomes, while LGA increases the risk of birth complications. Both SGA and LGA were reduced in association with EVOO intake.
  • Both GDM and prematurity were reduced in one or more of the interventional studies. The anti-diabetic effects of EVOO may be attributed to the activity of polyphenols, which can improve insulin sensitivity.
  • Two studies evaluated the risk of preeclampsia: increased EVOO consumption reduced the risk in one study; the other did not find a reduced risk of preeclampsia but reported a reduction in gestational weight gain, a risk factor for preeclampsia.

This systematic review is an important, first-of-its-kind summary of the evidence that EVOO can confer protective effects on pregnancy outcomes. More studies focusing on the impact of olive oil consumption on maternal-fetal outcomes are needed.

Reference: Cortez-Ribeiro, AC et al. Olive oil consumption confers protective effects on maternal-fetal outcomes: a systematic review of the evidence. Nutr Res. 2022;110:87-95. doi.org/10.1016/j.nutres.2022.12.013.