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. 

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.

Asparagus with Olive Oil Sabayon

Fresh asparagus is one of my favorite vegetables, especially when paired with a luscious olive oil sabayon. If not using the asparagus immediately, trim the ends (as you would cut flowers) and stand upright in a tall glass of water. Cover the tips with a plastic bag and refrigerate for a day or two.

Ingredients

  • 1 cup dry white wine
  • 1/3 cup white wine vinegar
  • 1 pound green or white asparagus, tough ends trimmed
  • 2 egg yolks
  • 1/3 cup extra virgin olive oil
  • Coarse salt (kosher or sea) and freshly ground black or white pepper

Directions

Step 1

Place the wine and vinegar in a saucepan and bring to a simmer over medium-high heat. Reduce the mixture by three-quarters and let cool.

Step 2

Steam the asparagus in a double boiler over medium-high heat until tender, about 8 to 10 minutes; set aside but keep warm.

Step 3

Transfer the wine reduction to the top of a double boiler and add the egg yolks. Set over simmering water over medium heat. Cook, whisking constantly, until the yolks thicken enough to fall into thin ribbons when the whisk is lifted from the pan. Remove the pan from the heat and gradually whisk in the olive oil. Thin, if necessary, with one to two tablespoons of water. Season with salt and pepper.

Step 4

Arrange the asparagus on a platter, spoon on the sauce, and serve.

Serves 4 — Recipe adapted from saveur.com

Cod with Chorizo and Breadcrumbs

A splash of sherry or red wine vinegar cuts the richness of the chorizo and brightens the flavors. Find cured Spanish chorizo online or in the international aisle of your supermarket. (Do not confuse cured, salami-like Spanish chorizo with raw Mexican chorizo, which must be cooked before using.)

Ingredients

  • 2 slices country-style bread, crusts removed
  • 4 tablespoons extra virgin olive oil, divided
  • Coarse salt (kosher or sea) and freshly ground black pepper
  • 1 tablespoon chopped flat-leaf parsley
  • 1 tablespoon chopped oregano
  • 1 small shallot, peeled and thinly sliced
  • 2 ounces smoked Spanish chorizo, halved and thinly sliced
  • 2 tablespoons sherry vinegar or red wine vinegar
  • 4 skinless cod or halibut fillets, each about 6 ounces

Directions

Step 1

Heat the oven to 425°F. Pulse the bread in a food processor until coarse crumbs form. Heat a large ovenproof skillet over medium-high heat. Add the olive oil and breadcrumbs. Cook, stirring often, until the bread crumbs are golden and crisp, about 3 minutes; season with salt and pepper. Transfer the mixture to a bowl, add the parsley and oregano, and toss to combine. Wipe out the skillet.

Step 2

Heat the same skillet over medium-high heat. Add a tablespoon of olive oil as well as the shallot and chorizo, and cook, stirring often, until the chorizo is just crisp, about 2 minutes. Transfer the mixture to a bowl and stir in the vinegar; season with salt and pepper. Wipe out the skillet.

Step 3

Heat the same skillet over medium-high heat. Add a tablespoon of olive oil. Season the cod with salt and pepper and cook until the bottom side begins to turn opaque, about 3 minutes. Transfer the skillet to the oven and roast until the fish is cooked through, about 5 minutes longer. Serve the cod topped with the chorizo mixture and toasted breadcrumbs.

Serves 4 — Recipe adapted from bonappetit.com