The facts that you should know about olive oil and other vegetable oils (including coconut oil) are:
Vegetable oils have more than twice the calorie density of refined sugar
Vegetable oils contain almost no vitamins, minerals or fibre
Olive oil is harmful to your arteries
The Mediterranean diet was healthy because it was mainly plant based
Whole plant foods contain all of the essential fats that our bodies require
“Isn’t olive oil good for you”? Is the surprised reply we get when we say “no oil, not even olive oil”. Doctors, dieticians, nutrition advisory groups and the media all promote olive oil as the good oil, the heart friendly oil, the key ingredient of the Mediterranean Diet. How could they collectively get this so wrong? The following is a summary of some of the evidence that olive oil is not a healthy addition to your diet.
The ultimate junk food?Olive oil is a highly processed food – it is olives stripped of their fibre, minerals and vitamins (with the exception of vitamin E). Oils have the highest energy density of any food, more than twice that of sugar (oils =9 calories/37kJ per gram; sugar =4 calories/16kJ per gram). One Australian tablespoon olive oil =160 calories/680kJ; 100ml =810 calories/3400kJ. Even the addition of small amounts of oil to food promotes weight gain and reduces nutrient intake: e.g. 100g wholemeal pasta (uncooked) = 332 calories; add 1 tablespoon olive oil: 160 + 332 = 492 calories. That’s 50% more calories for little nutritional benefit. You could have added another 48g pasta to the meal for the same number of calories. An extra 50g pasta would give you 4.9g fibre, 2mg iron, 31mg calcium, 0.7mg zinc and 42mg magnesium. The tablespoon of oil gives you none of those nutrients, so it could be said that olive oil “displaces” nutrients. See related pages: Energy Densityand Nutrient Density.
NB 1 tablespoon olive oil has the same number of calories as a 375ml can of Coke.
Vitamin EOlive oil contains vitamin E. In fact, many vegetable oils are high in vitamin E because it’s a fat soluble vitamin that is retained when the fats are extracted from their whole plant-food source. Vegetable oils appear high in vitamin E because they are a food concentrates – on a per calorie basis, they are no higher than the plants from which they were made. Many whole plant foods, including whole grains, are rich in vitamin E, and our digestive systems evolved the capacity to absorb this fat soluble vitamin long before the invention of salad dressing.
Fatty acid Composition: The term “good fats” is often applied to Olive oil. This description does not stand up to scrutiny unless you are comparing olive oil to animal fats. Olive oil consists predominantly of omega 9 monounsaturated fats which are not required by humans other than as a concentrated source of calories. It may surprise you that olive oil is moderately high in saturated fats – 15% – and therefore no amount of olive oil added to the diet will bring the proportion of saturated fats down the target of less than 10% of calories.
We need some dietary fats – the omega 6 and the omega 3 essential fatty acids. The omega 6 series are found widely in food and it’s thought that the Australian diet provides far too many omega 6 fats relative to omega 3’s compared to the suggested optimal ratios of 4:1 or less. Olive oil contributes excessive omega 6’s with less than 1% omega 3’s and a ratio of 13:1.
Polyphenols Polyphenols are anti-oxidant phytochemicals with health supporting effects which include protection against heart disease. Extra-virgin olive oil (EVOO) is promoted as healthy because it contains polyphenols. Most of the olive oil used in cooking is not polyphenol rich EVOO and there are many whole plant foods that have a much higher polyphenol content than EVOO. This table shows the polyphenol content of popular plant foods, and also shows the content per 100 calories. Compare eating 100g strawberries (235mg polyphenols; 26 calories) with a 20ml tablespoon EVOO (12mg polyphenols; 160 calories).
Polyphenol content of food
PER 100 CALORIES
Wholegrain wheat flour
Extra Virgin Olive Oil
Source: Perez-Jimenez et. al. (2010)
Mediterranean Diet of Crete:
Observations of the people of Crete post World War II found a low incidence of heart disease. The people there were physically active and their diet consisted of grains, fruits, vegetables and legumes and small amounts of olive oil, wine and fish. Not exactly the Australian version of the Mediterranean diet. Fifty years later a follow up study found that those individuals who consumed the most olive oil had the most heart disease (see Vrentzos et al. 2007). A similar positive association between olive oil and heart disease has been found in Greece.
The Lyon study:
This is the study that really launched “The Mediterranean diet”, and by proxy, olive oil, as heart healthy. The study group were instructed to make healthier food choices, including eating more vegetables. The vegetable oils used were not exclusively olive oil but included omega-3 enriched canola oil.
The PREDIMED study
The study is widely seen as ‘proof’ that a Mediterranean diet with olive oil is more heart healthy than a low fat diet. However the “low fat diet” group were really a control group on a high (37%) fat diet and there was not a statistically significant reduction in heart events – although there was a small reduction in strokes in both the added nuts and added olive oil intervention groups. It cannot be determined whether the olive oil or the nuts produced these health benefits as these groups also received dietary coaching and consumed more legumes, vegetables and fruits – factors which are known to reduce cardiovascular risk. The olive oil group were provided with a weekly supply of polyphenol rich olive oil, not the ordinary stuff that most people buy in the supermarket. The data collected in this study has resulted in over 100 published research articles and whenever we read “Mediterranean diet is better than a low fat diet” it’s usually based on PREDIMED.
Effects of oil on arteries
Olive oil and polyunsaturated oils raise HDL cholesterol, however changing the value of a biomarker for disease does not always translate into reduced disease risk. Dr Lawrence Rudel (Rudel et al 1995) compared the effects of saturated fat vs olive oil on African Green Monkeys (which have similar fat metabolism to humans). The monkeys eating olive oil had higher HDL and lower LDL than those eating saturated fat. But at the end of five years both groups had exactly the same amount of coronary artery disease. It is interesting to note that drugs that artificially raise HDL have also failed to protect against heart disease.
Dr Robert Vogel published a study (Vogel et al 2000) on the effect of vegetable oils on the arterial flow. Olive oil reduced arterial blood flow by 31% and canola oil by 10%. It is thought that olive oil blocks the production of nitric oxide by the endothelium. Nitric oxide dilates arteries. This suggests that olive oil impairs the capacity of endothelial cells to produce the vasodilator, nitric oxide.
Australian Dietary Guidelines
The Australian Dietary Guidelines do not support the high intake of olive oil that many of our health professionals are advocating. The guidelines recommend that we choose foods from the five food groups, none of which include olive oil. Vegetable oils are listed outside of the core food groups with a note to “use in small amounts”.
The guidelines recommend that Australians “limit” their consumption of high saturated fat foods rather than just replace them with other fats. Tips to eat less saturated fat include “don’t deep fry foods” and “use small amounts of unsaturated oils if needed”.
The guidelines recognise the role of energy dense foods in promoting weight gain: “Foods with a higher energy density encourage energy intake above requirements” – and recommend that Australians limit the consumption of “energy-dense, nutrient-poor discretionary foods”. Oils are the most energy dense foods, they contain minimal nutrients and are discretionary in that they do not belong to any of the five food groups.