Kalamata olives are a type of olive named after the city of Kalamata, Greece, where they were first grown.

Like most olives, they’re rich in antioxidants and healthy fats and have been linked to multiple health benefits, including protection against heart disease.

This article tells you all you need to know about kalamata olives.

Origin and uses

Kalamata olives are dark-purple, oval fruits originally from the Messinia region in Greece (1).

They’re cataloged as drupes, as they have a central pit and fleshy pulp. Despite their purple color and bigger size, they’re often classified as black table olives.

While they may be used for oil production, they’re mostly consumed as table olives. Like most olives, they’re naturally bitter, which is why they’re usually cured or processed prior to consumption.

The Greek-style curing practice places the olives directly in brine or saltwater, where they’re fermented with yeasts to remove their bitter compounds partially or entirely, thus improving the taste (1).

Summary

Kalamata olives are dark purple and originate from Greece. They’re cured in brine to remove their bitter compounds and improve the taste.

Nutritional profile

Unlike most fruits, kalamata olives are high in fat and lower in carbs.

A serving of 5 kalamata olives (38 grams) provides (2):

  • Calories: 88
  • Carbs: 5 grams
  • Fiber: 3 grams
  • Protein: 5 grams
  • Fat: 6 grams
  • Sodium: 53% of the Daily Value (DV)

Compared with other fruits, they’re high in fat. Around 75% of the fat is heart-healthy monounsaturated fatty acids (MUFAs), namely oleic acid — the most commonly consumed MUFA, which may help prevent heart disease and support cancer treatment (2, 3, 4).

Additionally, kalamata olives are a good source of minerals like iron, calcium, and copper, which may reduce your risk of anemia, strengthen your bones, and improve heart function, respectively (5, 6, 7, 8).

They also provide the fat-soluble vitamins A and E. Vitamin A is essential for maintaining healthy vision, while vitamin E is a potent antioxidant that may improve heart health (2, 9, 10).

It’s also worth keeping in mind that ready-to-eat olives have a high sodium content, mostly resulting from the brining process.

Summary

Kalamata olives are rich in oleic acid, a type of MUFA linked to improved heart health and cancer-fighting properties. They’re also a good source of iron, calcium, copper, and vitamins A and E.

Potential benefits

Kalamata olives have been associated with a variety of health benefits thanks to their high content of potent beneficial plant compounds.

Packed with antioxidants

Kalamata olives contain a wide range of antioxidants, which are molecules that fight free radicals in your body and reduce your risk of certain chronic diseases. Among them, a group of plant compounds called polyphenols stands out (11).

Two main types of polyphenols found in olives are oleuropein and hydroxytyrosol (12, 13).

Oleuropein accounts for roughly 80% of the total phenolic content in raw olives — this is the compound responsible for their bitter taste. During processing, most of the oleuropein is degraded into hydroxytyrosol and tyrosol (3).

Both oleuropein and hydroxytyrosol possess potent antioxidant and anti-inflammatory properties that protect against heart disease and may prevent cancer-induced DNA damage (14, 15, 16).

May promote heart health

Kalamata olives are rich in MUFAs — namely oleic acid — which are linked to a lower risk of heart disease (17).

Research suggests that oleic acid may reduce inflammation associated with obesity. It may also reduce atherosclerosis, or the buildup of plaque in your veins, a condition that can lead to high blood pressure and an increased risk of stroke (3, 18, 19).

What’s more, oleic acid has a fast oxidation rate, meaning that it’s less likely to be stored as fat and more likely to be burned for energy in your body (20).

This said, research suggests that the olives’ antioxidant content may have an even stronger influence than MUFAs on heart health (1).

For example, studies show that oleuropein and hydroxytyrosol offer cholesterol- and blood-pressure-lowering effects (14, 15, 21).

They also inhibit LDL (bad) cholesterol oxidation, a process associated with plaque buildup (3, 22, 23, 24, 25).

May offer cancer-fighting properties

Oleic acid and antioxidants in kalamata olives may also protect against certain types of cancer.

Test-tube studies suggest that oleic acid may lower the expression of the human epidermal growth factor receptor 2 (HER2) gene, which can turn a healthy cell into a tumor cell. Thus, it may play a role in regulating the progression of cancer (4, 26).

Similarly, oleuropein and hydroxytyrosol have demonstrated antitumor activities that block the growth and spread of cancer cells, as well as promote their death (15, 25, 27).

Animal studies suggest that both of these antioxidants may have a preventive effect on skin, breast, colon, and lung cancer, among other types of cancer (15, 23, 28).

What’s more, one test-tube study determined that oleuropein may lower the toxic effect that the anticancer drug doxorubicin has in healthy cells —without causing it to lose its cancer-fighting effect (14).

May protect nerve cells from damage

Many neurodegenerative diseases that cause brain cells to deteriorate, such as Parkinson’s and Alzheimer’s disease, result from the damaging effects of free radicals (15).

Given that antioxidants combat free radicals to neutralize their harmful effects, antioxidant-rich kalamata olives may help protect against these conditions.

Test-tube and animal studies have found the polyphenol oleuropein to be an important neuroprotector, as it may protect against brain cell loss associated with Parkinson’s disease and lower amylose plaque aggregation linked to Alzheimer’s disease (15, 22, 23, 29).

Other potential benefits

Due to their antioxidant content, kalamata olives may provide other health benefits, such as:

  • Antimicrobial and antiviral effects. Oleuropein has antimicrobial and antiviral properties and may fight certain bacteria and viruses, including herpes and rotavirus (15, 23).
  • Improved skin health. Oleuropein may protect against skin damage from ultraviolet B (UVB) rays (15, 23).

Though this research is encouraging, it has focused on test-tube studies that analyze individual components only.

Currently, no studies have directly evaluated the effects of eating kalamata olives on heart health, cancer, and neurodegenerative diseases. Thus, further research is needed to validate these effects.

Summary

The oleic acid and antioxidants in kalamata olives, such as oleuropein and hydroxytyrosol, may have cancer-fighting properties and benefit your heart and mental health.

Safety and precautions

Kalamata olives undergo a curing process to improve their taste.

This includes submerging them in brine or saltwater, which increases their sodium content. High sodium intake is a risk factor for high blood pressure (30, 31).

As such, you should moderate your intake or opt for low salt alternatives.

Additionally, there are both whole and pitted kalamata olives. While there are no nutritional differences between them, pits in whole olives are a choking hazard for children. Thus, make sure to serve them only pitted or sliced varieties.

Summary

Due to brining, eating kalamata olives may increase your sodium intake. Also, keep in mind that whole varieties are a choking hazard for kids.

How to add them to your diet

Kalamata olives have a strong, tangy flavor that can enhance many of your favorite recipes.

Here are a few ideas regarding how to add them to your diet:

  • Mix them with diced tomatoes, cucumber, and feta cheese for a Mediterranean-style salad.
  • Add them as a topping on pizza, salad, or pasta.
  • Remove their pits before using a food processor to blend them with capers, olive oil, red wine vinegar, garlic, and lemon juice for a homemade tapenade or spread.
  • Enjoy a handful as part of a healthy snack or appetizer.
  • Mince them and mix with olive oil, apple cider vinegar, lemon juice, and crushed garlic for a kalamata salad dressing.
  • Slice or dice them and add to bread dough for a loaf of homemade olive bread.

You can find whole or pitted kalamata olives in stores, so be mindful of pits when eating or cooking with whole olives.

Summary

Kalamata olives’ strong flavor makes them a great addition to many dishes, such as salads, pasta, pizza, and dressings.

The bottom line

Originating from Greece, kalamata olives are a type of dark-purple olive generally bigger than regular black olives.

They’re packed with beneficial nutrients and plant compounds that offer protective effects against certain heart and mental diseases.

However, since most of the available research has been conducted in test-tubes and examined their individual components only, further research is needed to better understand the benefits of eating kalamata olives.

You can add kalamata olives to a wealth of recipes — just be wary of pits if choosing whole over pitted ones.