I’m addicted to olives. Seriously. Addicted. I absolutely love them – you know the ones you get from the Farmer’s Market where they’re displayed in their many enticing varieties… Yum!
But a couple of weeks ago, my partner, whom I’ve introduced to olives and now shares in my addiction, asked me a simple question… Are olives healthy? “Yes,” I said. And then went on vaguely about them being a fruit, so they must be healthy.
But that question got me thinking… The many wonderful health benefits of olive oil have been known for centuries. But, olives themselves, don’t seem to get as must press… So are the fruit of the olive tree as good for our health as their oil?
Hold on to your hats, we’re about to get a bit scientific!
Dozens of health-protective nutrients have been identified in olives. Greek-style black olives, Spanish-style green olives, Kalamata-style olives, and many different methods of olive preparation provide us with valuable amounts of many different antioxidant and anti-inflammatory nutrients. While there are trade-offs that occur during olive ripening and olive curing—for example, decreased oleuropein with advanced stages of ripening yet increased amounts of anthocyanins—it’s impossible to rule out any single type of olive as being unworthy of consideration as a uniquely health-supportive food, particularly in terms of antioxidant and anti-inflammatory benefits.
Olives are a remarkable source of antioxidant and anti-inflammatory phytonutrients. Most prominent are two simple phenols (tyrosol and hydroxytyrosol) and several terpenes (especially oleuropein, erythrodiol, uvaol, oleanolic acid, elenoic acid and ligstroside). Flavonoids (including apigenin, luteolin, cyanidins, and peonidins) are typically provided in valuable amounts by lives, as are hydroxycinnamic acids like caffeic acid, cinnamic acid, ferulic acid, and coumaric acid. The phytonutrient content of olives depends upon olive variety, stage of maturation, and post-harvest treatment. Olives are a very good source of monounsaturated fat (in the form of oleic acid) and a good source of iron, copper, and dietary fibre.
Olives are a good source of the antioxidant vitamin E, and they also contain small amounts of antioxidant minerals like selenium and zinc. However, it’s the phytonutrient content of olives that makes them unique as an antioxidant-rich food.
Perhaps the best-studied antioxidant phytonutrient found in olives is oleuropein. Oleuropein is found exclusively in olives, and it’s been shown to function as an antioxidant nutrient in a variety of ways. Intake of oleuropein has been shown to decrease oxidation of LDL cholesterol; to scavenge nitric oxide (a reactive oxygen-containing molecule); to lower several markers of oxidative stress; and to help protect nerve cells from oxygen-related damage.
Interestingly, there may be common trade-offs made in the levels of different olive antioxidants during the maturation of olives on the tree. For example, the vitamin E content of olives may increase during early ripening when the total phenolic antioxidants in olives are slightly decreasing. Later on in the maturation process, these trends may be reversed.
In addition to their function as antioxidants, many of the phytonutrients found in olives have well-documented anti-inflammatory properties. Extracts from whole olives have been shown to function as anti-histamines at a cellular level. By blocking special histamine receptors (called H1 receptors), unique components in whole olive extracts help to provide us with anti-inflammatory benefits. Oleuropein – one of the unique phytonutrients found in olives – has been shown to decrease the activity of inducible nitric oxide synthase (iNOS), an enzyme whose over-activity has been associated with unwanted inflammation.
The anti-inflammatory benefits of olives have been given special attention in the area of cardiovascular health. In heart patients, olive polyphenols have been determined to lower blood levels of C-reactive protein (CRP). CRP is a widely used blood measurement for assessing the likelihood of unwanted inflammation. Olive polyphenols have also been found to reduce activity in a metabolic pathway called the arachidonic acid pathway, which is central for mobilizing inflammatory processes.
The antioxidant and anti-inflammatory properties of olives make them a natural for protection against cancer because chronic oxidative stress and chronic inflammation can be key factors in the development of cancer. If our cells get overwhelmed by oxidative stress (damage to cell structure and cell function by overly reactive oxygen-containing molecules) and chronic excessive inflammation, our risk of cell cancer is increased. By providing us with rich supplies of antioxidant and anti-inflammatory nutrients, olives can help us avoid this dangerous combination of chronic oxidative stress and chronic inflammation.
Research on whole olives and cancer has often focused on two cancer types: breast cancer and stomach (gastric) cancer. In the case of breast cancer, special attention has been paid to the triterpene phytonutrients in olives, including erythrodiol, uvaol and oleanolic acid. These olive phytonutrients have been shown to help interrupt the life cycle of breast cancer cells. Interruption of cell cycles has also been shown in the case of gastric cancer.
And, of course, all of these antioxidant and anti-inflammation properties are good news for our skin as well.
The most common skin complaints seen today – acne, eczema, psoriasis, even rosacea – can be seen as inflammatory diseases. Toxic build-up within our bodies triggers inflammation as a protective response; a way for our cells and tissues to cushion themselves from the worst of the toxic attack. But, as a side effect, this inflammation also causes the skin problems which have become so common.
And I’m sure we’ve all heard about the antioxidant effects on premature ageing. As we age, our skin naturally gradually loses many of its properties. Antioxidants help to slow this ageing process by neutralising the damaging effects of our environment.