That fruity-grassy aroma, slightly bitter taste, and pungent peppery bite that you can feel in the back of your throat are all signs of a fresh, ultra healthy olive oil. Why? These qualities are key indicators that your olive oil is brimming with potently nutritious bioactive compounds.
Olive oil's bioactive compounds—including various olive oil polyphenols (e.g. oleuropein, hydroxytyrosol and oleocanthal), oleic acid, phytosterols, and more—are known for their antioxidant and anti-inflammatory properties. The interplay between these compounds is also the reason olive oil is associated with so many health claims such as reduced risk for cancer and heart disease.
Compared to other culinary oils, olive oil is the richest source of bioactive compounds, but not all olive oil is created equal. Levels of bioactive compounds will differ depending on the type of olive oil (for example, extra virgin olive oil and virgin olive oil contain the highest levels of polyphenols), olive varieties used, growing conditions, time of olive harvest, storage conditions, and more.
Additionally, the fresher the olive oil, the greater the levels of bioactive compounds—and flavor! So you'll always want to consume your olive oil within a reasonable amount of time (pro tip: unlike wine, olive oil doesn't age well). Try not to go past the "best buy" date.
What Are Bioactive Compounds? More Than Just Antioxidants
Bioactive compounds are natural chemical molecules that typically occur in small amounts in plant foods such as vegetables, fruits, seeds, nuts, oils, and whole grains—and they have beneficial effects on health, including their antioxidant properties and free radical-scavenging potential.
There are many classes and subclasses of dietary bioactive compounds being studied for their ability to improve various biomarkers of health and reduce risk of chronic diseases—including those present in extra virgin olive oil.
A number of recent lab and in vivo studies (on animals and humans) suggest that the bioactives in olive oil may have the following health benefits, and possibly more:
- Anti-inflammatory benefits and pain relief
- Antimicrobial properties
- Improved insulin sensitivity
- Reduced oxidative stress
- Anticancer properties (e.g. increased apoptosis, reduced proliferation)
- Improved blood lipids (e.g. reduced LDL cholesterol and triglycerides)
- Reduced LDL oxidation
- Reduced platelet aggregation and risk of blood clots
- Regulation of genes associated with various diseases
Bioactive Compounds Found In Olive Oil & Why They're So Healthy
A high quality olive oil is absolutely packed with bioactive compounds—which is probably a big reason people eating a Mediterranean diet tend to be so healthy. While there are too many to list here, we’ve rounded up the bioactives with the strongest health benefits, all supported by recent studies. These include:
- Hydroxytyrosol (and its precursor oleuropein)
- Oleic acid
1. Biophenols (a.k.a. polyphenols or phenolic compounds)
Biophenols is the term used to refer to the polyphenol compounds (sometimes called phenolic compounds) present in olive oil. So when a company refers to their olive oil as "high phenolic olive oil," they’re trying to say it’s high in these beneficial olive oil polyphenols, which include hydroxytyrosol, tyrosol, oleuropein, oleocanthal, caffeic acid, lignans, flavones, and more.
Biophenols are one of the most robustly studied groups of olive oil bioactive compounds, with research demonstrating their antioxidant properties and protective effects against oxidative stress—a type of physiological stress that can cause DNA mutations and lead to cancer, diabetes, cardiovascular diseases such as heart disease, and neurodegenerative disorders such as Alzheimer’s.
While there are many different biophenols present in extra virgin olive oil, the most well studied are hydroxytyrosol and oleocanthal, so we’ll be diving a bit deeper into their benefits here.
Hydroxytyrosol is one of the most well-studied olive oil polyphenols/ phenolic compounds, and it's known for contributing to many of olive oil’s health benefits. It’s also present in the olive fruit and leaves, which can be used to make hydroxytyrosol-rich olive leaf extract supplements.
Hydroxytyrosol is so beneficial that European regulation states that an olive oil product can only claim health benefits provided there are at least 5 mg of hydroxytyrosol (and its derivatives) present per 20 g (or about 2 tbsp) of olive oil.
Important to note: Hydroxytyrosol is a metabolite (or a breakdown product) of another olive oil phenolic: oleuropein. As olives ripen, some oleuropein is converted into hydroxytyrosol within the olive fruit; then as you eat and digest olive oil, much of the remaining oleuropein is converted into hydroxytyrosol in your body.
The beneficial effects of hydroxytyrosol are highlighted below.
Benefits of Hydroxytyrosol
Scientific studies suggest hydroxytyrosol has the following health-boosting properties:
- Anti-inflammatory: Hydroxytyrosol helps combat inflammation through a variety of mechanisms, like prompting immune cells called cytokines to make an anti-inflammatory compound called interleukin-10 (IL-10).
- Antioxidant: Hydroxytyrosol’s proven antioxidant activity may be one reason olive oil has been linked to reduced risk of cancer and improvements in blood lipids like cholesterol. For example, hydroxytyrosol and oleuropein seem to help prevent LDL cholesterol (low-density lipoprotein) from oxidizing into an even more harmful form of cholesterol. Some research suggests that olive oil polyphenols exert this effect by restoring levels of glutathione, which is considered the body's "master antioxidant."
- Anticancer: Hydroxytyrosol has been shown to induce apoptosis (programmed cancer cell death) and interfere with the ability of cancer cells to grow new blood vessels and metastasize (spread to other parts of the body).
- Antimicrobial: Hydroxytyrosol is antimicrobial and has been shown to halt or delay the rate of growth of a variety of harmful intestinal and respiratory bacteria in lab studies. Even more impressive, in human studies, olive oil has been shown to help combat bacteria-induced H. pylori infections in the gut, thanks to hydroxytyrosol and other polyphenols.
- Anti-thrombotic: Hydroxytyrosol is considered anti-thrombotic (meaning: able to reduce the formation of blood clots), since it significantly reduces platelet aggregation or build up.
Oleocanthal falls under the umbrella of secoiridoids, and it's the polyphenol/ phenolic compound responsible for giving extra virgin olive oil its classic peppery bite. In fact, if your olive oil doesn’t have a slight bite to it, it’s probably low in polyphenols. Oleocanthal has similar properties to hydroxytyrosol, plus a few unique perks.
Benefits of oleocanthal
Scientific studies suggest oleocanthal has the following health-boosting properties:
- Neuroprotective: Oleocanthal-rich olive oil may help slow the progression of Alzheimer’s disease by improving blood-brain barrier function and reducing neuroinflammation, according to a recent study on animals.
- Anti-inflammatory + pain-fighting: Oleocanthal doesn’t just reduce inflammation, it may be a potent pain fighter, too, since it has a similar mode of anti-inflammatory action as ibuprofen—the inhibition of COX1 and COX2 enzymes.
- Antioxidant: Oleocanthal has proven antioxidant activity, and one recent study demonstrated its ability to protect neurons from oxidative damage caused by free radicals, suggesting it could play an important role in overall nervous system and mental health.
- Anticancer: Like hydroxytyrosol, oleocanthal has been shown to slow cancer cell growth and trigger apoptosis (programmed cell death) on cancer cells in lab studies.
- Anti-microbial: Oleocanthal likely acts synergistically with hydroxytyrosol to have an antimicrobial effect against harmful pathogens in the body.
2. Oleic acid
Oleic acid is an extremely beneficial type of monounsaturated fatty acid. Olive oil can be composed of up to 83% oleic acid—more than any other oil.
- Anti-inflammatory: Out of all the monounsaturated fatty acids, oleic acid seems to be particularly good at reducing inflammation.
- Anticancer: Numerous studies have shown that oleic acid may help suppress certain genes associated with breast cancer and cancers of the brain.
- Heart-healthy: Consumption of oleic acid rich foods has been associated with reductions in blood lipids, including overall cholesterol, LDL cholesterol, and triglycerides.
- Anti-diabetes: Recent research shows that oleic acid has protective effects against insulin resistance, which is a main driver of type 2 diabetes. Not to mention, any type of healthy fat helps keep blood sugar levels balanced.
Phytosterols are a class of bioactive compounds found in olive oil and a number of other healthy plant foods, including nuts and whole grains. Olive oil contains several phytosterols, including B-sitosterol and campesterol.
- Heart-healthy: Phytosterols are similar in composition to cholesterol and they actually help block it from being absorbed.
- Anticancer: Emerging evidence suggests phytosterols may have anti-tumor properties—they've been shown to reduce cancer cell proliferation and breast cancer tumor growth in animals.
Squalene is a triterpene acid found in olive oil. In fact, olive oil is composed of about 0.7% squalene—more than just about any food.
- Antioxidant: Squalene helps scavenge reactive oxygen species (including free radicals) in the body and has an overall antioxidant effect.
- Anticancer: Squalene from olive oil is believed to be partly responsible for the lower incidence of skin cancer among people in the Mediterranean region.
Tocopherols is just a fancy way to say vitamin E, and a teaspoon of olive oil contains about 10% of your daily value for this nutrient. Olive oil's tocopherols have topical benefits, too!
- Antioxidant: Tocopherols have a beneficial effect on blood lipids and seems to be particularly good at helping prevent lipid (fat) oxidation that might otherwise trigger widespread inflammation.
- Heart-healthy: Emerging evidence suggests tocopherols may help prevent atherosclerosis-related cardiovascular disease.
- Skin-soothing: The combo of vitamin E plus nourishing fatty acids can help alleviate skin conditions like eczema from the inside out.
How To Tell If Your Olive Oil Is High In Polyphenols & Other Bioactive Compounds
According to Dr. William Li, M.D., internal medicine physician and author of Eat to Beat Disease, olive oil monovarietals made from Koroneiki, Picual, and Moraiolo olives are a surefire way to ramp up your dietary intake of polyphenols—research suggests they have the highest levels. Specialty olive oil retailers are more likely to carry these monovarietals.
But these aren’t the only olive oils that pack a bioactive punch—in general, extra virgin olive oils will contain the highest concentration of polyphenols, as long as they’re not too old, and all types of olive oil contain relatively equal amounts of phytosterols, oleic acid, and vitamins E and K. As for country of origin? Spain, Italy, Morocco, and even several U.S. states like California and Texas all produce high quality, bioactive-packed olive oil
Wondering if the olive oil in your pantry is up to snuff? Do an olive oil taste test: Pour a tablespoon or two into a cup, then take a small sip as you would during a wine tasting—aerating the oil a bit as you move it from the front to the back of your palate.
You should notice a somewhat peppery, bitter taste (it might even make you cough), which is an indicator of a high polyphenol content. A pleasant grassy, vegetal, or floral flavor is also a good sign. But it should never taste rancid.
Bottom Line On Olive Oil Bioactives
Clearly, olive oil owes many of its health benefits to its powerful bioactives. And because it's one of the richest dietary sources of these compounds on the planet, using a high quality extra virgin olive oil for most of your culinary needs can go a long way in supporting your body and preventing disease.
Keep in mind: The polyphenols and other bioactives in EVOO act synergistically with the bioactives in other plant foods as well. Meaning, they boost each other's bioavailability and beneficial effects—so to really optimize health, try to load up on a variety of fruits, veggies, nuts, seeds, whole grains, and other nourishing foods typical of a Mediterranean diet.
Need more inspiration to ramp up your olive oil consumption? Check out our article on the 10 Science-Backed Health Benefits of Olive Oil.