Olive oil is a major contributor to health and a cornerstone of the colourful Mediterranean Diet, or the Rainbow Diet as we like to call it. The ‘healthiest’ olive oil is cold pressed olive oil, often called extra virgin olive oil. It is prepared from the first pressing of the olives and is completely natural and unrefined. Its benefits have been proven to be dose-dependent. The more you consume, the greater the health benefits.
In case you’re confused, the difference between an oil and a fat is temperature. Below a certain temperature, oils become fats.
Olive Oil has several different bioactive ingredients and actions:
1. Olive oil reduces inflammation:
Oleocanthol is a polyphenol unique to olive oil and it has powerful anti-inflammatory benefits. It acts like other NSAIDs (but without the side-effects) to inhibit both Cox-1 and Cox-2 and thus regulates inflammation(1).
Not surprisingly, it had been noted in the Seven Countries Study that the populations consuming good amounts of olive oil suffer far less from chronic inflammatory diseases, like chronic heart disease(2). In particular, there are a good number of research studies on how oleocanthal alleviates arthritis; for example, it reduces osteoarthritis and rheumatoid arthritis(3).
2. Olive oil, gut bacteria and inflammation
But, there is another way that olive oil works to boost your health by reducing inflammation – through your gut bacteria.
According to a number of studies by the Cleveland Clinic, a compound called trimethylamine N-oxide or TMAO is a highly inflammatory compound linked to higher risk of strokes, heart attacks, atherosclerosis and kidney failure. In a second study the researchers found a clear link between elevated levels of TMAO and heart attack, strokes and death. TMAO is produced in a two step process – first your gut bacteria can convert compounds such as l-carnitine and choline (from steak, dairy products, eggs, processed meats) in to TMA, then the liver turns it in to TMAO.
TMAO can also be produced from coconut oil.
However, olive oil blocks the formation of TMAO by reducing the numbers of bacteria that produce TMA, and ‘feeding’ greater numbers of bacteria that make anti-inflammatory molecules.
Go to: Olive oil vs Coconut oil
3. Olive oil compounds can kill cancer cells and limit cancer progression
Oleocanthal has also been shown to destabilise the lysosomal membranes of cancer cells causing their death whilst not harming healthy cells(4). Researchers noted its effects against breast, prostate and pancreatic cancer cells and showed rapid cancer cell death in 30-60 minutes. Oleocanthal has also been shown to inhibit cancer cell proliferation in multiple myeloma(5).
Oleic acid is the most common fatty acid in nature and the most common mono-unsaturated fat – it is also found in high levels in walnut, peanut, pecan, canola, sunflower and macadamia oil(6). A 2001 study showed that higher levels of oleic acid in red blood cell membranes was linked to a higher risk of breast cancer. However, the Lancet reports much more recent research showing that oleic acid can reduce progression of breast cancer by 30%(7). Many experts now think this conflict highlights the difference between oleic acid and oleate, the actual compound found in olive oil given that olive oil itself has been shown to help prevent breast cancer(8). Another study(9) showed how olive oil oleate could suppress HER-2 expression and enhance the effects of drugs like Herceptin.
Finally, in a meta-analysis(15) selecting 19 of 38 studies recorded between 1990 and 2011, involving 13,800 cancer patients and 23,340 controls, the researchers concluded that “Olive oil intake is inversely proportional to cancer prevalence”. And that, “The strength and consistency of the findings states a hypothesis about the protective role of olive oil intake on cancer risk. However, it is still unclear whether olive oil’s monounsaturated fatty acid content or its antioxidant components are responsible for its beneficial effects.”
4. Olive oil for weight loss and diabetes
The most quoted health benefit of olive oil is that it contains high levels of mono-unsaturated fat at 73%, and this is the prime source of fat in the Mediterranean Diet. Other oils also high in mono-unsaturated fat are consumed in certain areas of the Mediterranean, for example, nut oils such as walnut oil, vegetable oils like avocado oil, and seed oils such as sesame.
Oleic acid has been shown to reduce blood glucose, and oxidative pancreatic and liver stress.
One Spanish study on ‘metabolic syndrome’ showed that feeding animals one of olive oil, or butter, or a standard diet produced very different results. Although olive oil participants had higher overall cholesterol it was predominantly HDL or good cholesterol; and these animals also had lower insulin and leptin levels. Higher insulin levels are associated with high sugar levels and inflammation; while high leptin is linked to poor weight control.
Leptin is a hormone and levels fall when people fast, and lowered leptin levels are linked to weight loss.
The Diabetes Council states that the benefits of olive oil are not just in better insulin control but also the high level of antioxidants in olive oil help repair the free-radical damage caused by excess sugar in the blood, and thus reduce the risk of secondary effects like neuropathy, high blood pressure and cardiac issues.
5. Olive oil is good for heart health
American heart expert Dr. Chauncey Crandall in his Heart Health newsletter, has explained that eating saturated fats like red meat, is not as bad as originally thought, providing that the balance of oil consumption is firmly in favour of mono-unsaturated fats. Trans fats are, however, dangerous to your health and should be avoided. Equally, measuring an individual’s cholesterol level is meaningless, as within it there is good cholesterol and bad cholesterol. The issue is to have High Density Lipoprotein (HDL) levels considerably higher than Low Density Lipoprotein (LDL) levels.
Olive oil consumption is known to increase HDL and reduce LDL levels. More that ten studies link olive oil consumption to lower levels of cardiovascular disease, stroke, heart attack and thrombosis.
Olive oil lowers levels of circulating cholesterol and triglyceride. But, it seems that it’s not enough simply to have high HDL and low LDL; HDL has to be ‘activated’. In one study, amongst a random sample of participants in the PREDIMED study, extra olive oil, extra walnuts were assessed against people on a low fat diet. The olive oil and walnut groups had similar increases in HDL but the olive oil group showed much increased ability to esterify cholesterol and reduce atherosclerosis.
6. Olive oil and brain health
Several studies have indicated that olive oil could be important in brain health.
The first was a 2017 study from Edinburgh University showed that oleic acid could prevent genes causing cancer in the brain.
Researchers found that olive oil prevents the formation of a protein, MSI2, which can stop the production of miR-7, leading to brain cancer.
In another study, oleocanthol, was shown to reduce the build up of amyloid plaque, a pre-cursor of Alzheimer’s(11).
In a study(12) from the University of Louisiana Monroe, concentrates of oleocanthal have been shown to prevent both Alzheimer’s and cancer.
7. Olive oil and mental health
A study from researchers at Las Palmas de Gran Canaria followed over 12,000 adults for 6 years. The group consuming higher levels of olive oil (especially in conjunction with fish oils) had far less depression than the group who consumed unhealthy saturated and trans fats. In fact, the latter group had 48% more depression.
8. Olive oil has anti-microbial benefits
It possesses anti-microbial benefits and reduces the effects of Helicobacter pylori which can causes stomach ulcers and cancer, and ulcerative colitis in the gut(13). There is also evidence of reduced levels of colorectal cancer in people consuming good levels of olive oil.
9. Olive oil and a longer life
Consuming extra virgin olive oil (EVOO) has been shown to increase longevity. Researchers from Spain presented results in the Journal of Clinical Nutrition(14) showing that there was a direct link between a greater EVOO consumption and a lowered risk of dying during a 14 yea follow up period. They also found that fish oils and olive oil worked synergistically.
But then that’s the Rainbow Diet for you!
2. Keys A. Coronary heart disease in seven countries. Circulation. 1970;41:186–195.[PubMed]
3. Scotece M., Gómez R., Conde J., Lopez V., Gómez-Reino J.J., Lago F., Smith A.B., Gualillo O. Further evidence for the anti-inflammatory activity of oleocanthal: Inhibition of MIP-1α and IL-6 in J774 macrophages and in ATDC5 chondrocytes. Life Sci. 2012;91:1229–1235. doi: 10.1016/j.lfs.2012.09.012. [PubMed] [CrossRef]
8. Martin-Moreno JM, Willett WC, Gorgojo L, Banegas JR, Rodriguez-Artalejo F, Fernandez-Rodriguez JC, Maisonneuve P, Boyle P (1994). “Dietary fat, olive oil intake and breast cancer risk”. International Journal of Cancer. 58(6): 774–780. doi:10.1002/ijc.2910580604. PMID 7927867.
10. Santosh Kumar, Angela Downie Ruiz Velasco, Gracjan Michlewski. Oleic Acid Induces MiR-7 Processing through Remodeling of Pri-MiR-7/Protein Complex. Journal of Molecular Biology, 2017; 429 (11): 1638 DOI: 10.1016/j.jmb.2017.05.001