All About Olives: Five Reasons to Eat Them

Olives are one of the oldest cultivated trees worldwide, with the oldest known tree thought to be at least 2,000 -- and possibly more than 3,000 -- years old.[i] The tree, known as the "olive tree of Vouves" and located on the island of Crete, still produces olives and acts as a symbol of everything olives stand for -- longevity, prosperity and peace, for starters.

Valued for their oil for at least 6,000 to 8,000 years, humans have been embracing olives for food, medicine, cosmetics and other uses for centuries, including using their oil to light the original Olympic torch. Pliny the Elder reportedly described olives as one of the most important plants in existence, and as noted by National Geographic, "To destroy an enemy's olive trees, in Old Testament days, was the ultimate act of war."[ii]

Olives, though, are incredibly bitter in their raw form due to oleuropein, a compound the plant uses to ward off various predators. Birds still eat them, however, swallowing them whole to avoid the unpleasant flavor and helping to disperse their seeds in the process.[iii]

It's unclear exactly when humans discovered how to make olives palatable, but ancient Romans are often credited with figuring out that fermenting olives in brine with lye quickly got rid of the bitterness and rendered olives a tasty snack.[iv]

Why Eat Olives? Five Top Benefits

Olives are technically called drupes, which are fruits with a pit or stone in the middle. Other drupes include cherries, mangoes and nectarines. An estimated 90% of olives produced worldwide are used to make oil, consumption of which has tripled in the U.S. over the last two decades.[v] Whether you prefer to consume it as an oil or in whole form, there are many reasons to make olives a regular part of your diet.

In addition to providing a healthy source of monounsaturated fat, olives are rich in antioxidant and anti-inflammatory phytonutrients, including terpenes like oleuropein, flavones such as apigenin and luteolin, anthocyanidins, flavonols and hydroxybenzoic acids like gallic acid.[vi] Taken together, eating olives may play a role in reducing nearly 200 diseases and can provide a number of benefits to your health.

1. Reduce Oxidative Stress

Oleuropein is one of the most plentiful antioxidants in olives, which is also responsible for scavenging free radicals and reducing tissue damage caused by oxidative stress.[vii]

Olive fruit extract has also been found to protect against low-density lipoprotein (LDL) cholesterol oxidation,[viii] which is linked to heart disease. By lowering oxidative stress as a whole, olives may offer protection against a number of related metabolic disorders.[ix]

2. Support Heart Health

Olives are well-known for their heart-protective properties and have even been said to be largely responsible for the reduction of heart disease and oxidative stress seen among those following a Mediterranean diet,[x] which counts olive oil as a primary source of fat.

Polyphenolic compounds in olives have significant cardioprotective effects and support heart health in a multitude of ways, including:[xi]

  • Increase high-density lipoprotein (HDL)
  • Prevent oxidative stress
  • Reduce thrombogenic endothelial dysfunction
  • Support healthy blood pressure
  • Lower inflammation
  • Favorably alter gene expression responsible for atherosclerosis

3. Anticancer Effects

Oleuropein has significant anticancer effects and has been found to inhibit proliferation and induce apoptosis (programed cell death) by modifying important epigenetic factors in breast cancer cells.[xii] Researchers even stated oleuropein has the "potential to be a therapeutic drug for BC [breast cancer] prevention and treatment."[xiii]

4. Shorten Upper Respiratory Infections

Olive leaf extract is another of the olive plant's claims to fame, and its notable polyphenols, such as oleuropein and hydroxytyrosol, have antiviral, antibacterial, anti-inflammatory and antioxidant properties.[xiv]

When a group of high school athletes with sub-optimal diets in terms of immune support were given an olive leaf extract supplement, they experienced a 28% reduction in sick days for respiratory illness, suggesting that olive leaf helped to decrease the duration of infection.[xv]

5. Antidiabetic Effects

Consumption of olive oil is linked to a lower risk of developing Type 2 diabetes and improved glucose metabolism.[xvi] Hydroxytyrosol, one of the primary polyphenols in olive oil, is known to improve lipid profile and insulin sensitivity while reducing oxidative and inflammatory processes.[xvii]

Green, Black and Spanish: What's the Difference?

There are more than 1,000 olive varieties, but about 139 of them make up about 85% of worldwide olive production.[xviii] Picual and arbequina olives are popular for olive oil production, while mission olives, which are one of the primary varieties grown in California, are popular as table olives.

Kalamatas, a popular olive from Greece, are used for both table purposes and oil and are only harvested once they're fully ripened and dark purple to black in color.[xix]

For most people, however, olives are thought of as two main varieties: green or black. Green olives, which are also known as Spanish olives, are picked in their green, unripened state then cured prior to eating. Black olives, which come from California and are also known as California ripe olives, are also picked when they're green and firm.

A lye-based curing process involving exposure to air is what gives these "black" olives their final black color.[xx] When choosing olives, look for those processed using traditional curing instead of lye processing, which will maximize both the health potential and the flavor.

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