In a recent video I did with Zoë Harcombe PhD about the nutritional value of vegetables, she spoke about olive oil being “not all that”. I was shocked, along with many of you.
Surely olive oil is the healthiest food on the planet?
She suggested it would be better to eat olives than consume the oil which will be processed. “But olive oil is just crushed olives” many pointed out. I wrote to her personally to get more information and she decided to write an article explaining all the facts and the myths about olive oil.
Zoë’s article:
In terms of macronutrients, olive oil is 100% fat. It contains no protein or carbohydrate. It contains 884 calories per 100g. The fat in olive oil is 73g monounsaturated fat, 14g saturated fat and 11g polyunsaturated fat. Frustratingly, the numbers in foods databases rarely add to 100g (the fats here add to 98g). Nutrition is not an exact science.
In terms of micronutrients, olive oil has no minerals of any significance
It has no water soluble vitamins (that’s not surprising, as it’s 100% fat). That means it has none of the eight B vitamins or vitamin C. It has no vitamin A or D from the fat soluble vitamins. It has 14mg of vitamin E and 60mcg of vitamin K1 per 100g. To put this in perspective, 100g of sunflower seeds provides 35mg of vitamin E (Ref 6). That’s two and a half times the vitamin E as olive oil and for 300 fewer calories per 100g. For vitamin K1, kale would be far better than olive oil. It contains 390mcg of vitamin K1 per 100g of raw kale (Ref 7). That’s 6.5 times the amount of K1 and for only 35 calories, not 884. This is ignoring the fact that the body wants vitamin K2 and not K1, so no plant source is best. Olive oil is simply not best for any micronutrients.
Is olive oil natural?
It can be. If we consume olive oil, it needs to be extra virgin olive oil (EVOO). Regular olive oil is heated to extract the oil and refined, while extra virgin olive oil is cold-pressed and left unrefined. I would still suggest that we might be better off consuming olives, rather than olive oil, in much the same way that we are better off consuming oranges rather than orange juice. (It’s the most natural form of the food). Comparing 100g of olives with 100g olive oil, the olives contain traces of B vitamins, 52mg calcium, 11mg magnesium, 0.5mg iron and some phosphorus, selenium and zinc (Ref 8). Olives don’t have the levels of vitamins E and K that olive oil does. But what olives do provide are delivered in one sixth of the calories of olive oil.
A recent tweet grabbed my interest “There aren’t enough olive trees in the world for all the olive oil that’s supposedly produced” (Ref 9). Intuitively that makes sense. Many of the cheaper ‘olive oils’ are mostly other oils. If you search the UK’s largest grocery store web site for olive oil, the product Olivio oil comes up. Olivio oil is mainly rapeseed oil. Only 15% of the oil is olive oil, which is composed of refined and virgin olive oils (Ref 10).
While trying to understand what could be called olive oil on the label, I came across an interesting article in Forbes called “The olive oil scam – if 80% is fake why do you keep buying it?” by Cecilia Rodriguez (Ref 11). This article claimed, “It’s reliably reported that 80% of the Italian olive oil on the market is fraudulent.” The New York Times warned that “Much of the extra virgin Italian olive oil flooding the world’s market shelves is neither Italian, nor virgin.” Many adulterated olive oils are sold under quality brand names. The whole article is worth a read.
A December 2023 article in Food Safety News reported “Spanish and Italian investigators uncover olive oil fraud” (Ref 12).
Cheaper oils are being passed off as olive oil
If the oil can be labelled virgin or extra virgin, it commands a higher price. While on the subject of price, olive oil has rocketed in price over the last year (I can only comment on UK prices). I track some core products for my own ‘basket of inflation’ and 500ml of quality EVOO was £4.70 in March 2023 and it’s now between £8-£8.70. EVOO is thus a very expensive way of getting a couple of nutrients, which can be better obtained elsewhere.
Health claims made for olive oil and their counters (Ref 13)
1) Olive oil is rich in monounsaturated fat
It is, but there’s nothing special about monounsaturated fat. It’s one of three natural fats that nature puts in all foods that contain fat (which is virtually every food remember – at least a trace of fat).
While we’re on the topic of fat and olive oil, remember that we are told that fat is bad and saturated fat is worse (both false). Olive oil is claimed to be healthy and meat unhealthy – especially red meat. Yet, in 100g of grass fed steak there are 73.4g of water, 23.1g of protein and 2.7g of fat. Of this fat, 1g is saturated, 1g is monounsaturated and 0.1g is polyunsaturated (Ref 14).
So, per 100g, olive oil has 37 times the fat and 14 times the saturated fat of this steak. Ah but we wouldn’t consume 100g of olive oil you say. But 1 tablespoon of olive oil (14g) has twice the saturated fat of 100g of our grass fed steak. Food for thought.
2) Olive oil is high in antioxidants
It’s not. First, we should minimise oxidants (sugar, refined seed oils, smoking, pollution etc) and then we can worry less about needing antioxidants to counter them. Second, antioxidants are measured with the ORAC value. ORAC stands for Oxygen Radical Absorbance Capacity. It was developed by the National Institute of Health and Aging (NIH). The ORAC value measures the antioxidant capacity of different foods. The ORAC value for olive oil is 372 μ mol TE/100g (Ref 15). As a comparator, the ORAC value of brewed coffee is 2,780 μ mol TE/100g (Ref 16). The coffee is multiples better than the olive oil and the coffee delivers zero calories – not nearly 900.
3) Olive oil is anti-inflammatory
It’s not especially anti-inflammatory. First, we should minimise inflammatory things (wheat, sugar, refined seed oils, over exercising, smoking, pollution etc) and then we can worry less about inflammation. Second, it is claimed that polyphenols in EVOO can combat inflammation. EVOO contains about 500 mg/L of polyphenols (Ref 17). Berries can have 1,000 mg per half cup (Ref 18). Again – the claims for olive oil apply far more in another food and this time one with a few tens of calories – not nearly 900.
4) Olive oil can lower cholesterol
It can, but this is not good. Olive oil contains plant sterols. Plant sterols will lower cholesterol (replace human cholesterol with plant cholesterol more accurately) but my original research found that this is not good for heart disease or cancer (Ref 19).
5) The PREDIMED study showed the benefits of olive oil
No it didn’t. The study was supposed to be a randomised controlled trial. It wasn’t randomised (Ref 20) and it wasn’t controlled (Ref 21). It was a three way intervention where two groups were asked to follow a Mediterranean Diet – one with extra olive oil and the other with extra nuts. The olive oil group were supposed to consume at least 4 tablespoons (50 grams) of extra virgin olive oil per day. The nut group was supposed to consume 30 grams of mixed nuts (15 g walnuts, 7.5 g hazelnuts and 7.5 g almonds) daily. The third group was supposed to be a control group. A control group is supposed to change nothing – that’s the point of having a control group.
In PREDIMED, the control group changed more than the other two groups. The two intervention groups largely continued with the diet that they had been consuming (the so called Mediterranean Diet), while adding some olive oil or nuts. The control group was asked to follow a low-fat diet. They were told to limit olive oil, limit sofrito (see later in this note), limit fish and limit nuts. They were told to trim fat off everything and only eat low-fat dairy. PREDIMED showed that a low-fat diet was not as good as what people were eating before they joined the PREDMID control group.
6) Olive oil is associated with reduced risk of strokes/heart disease (and other health claims)
This is classic association nonsense. Healthy people (can afford to) consume olive oil. Healthy people are less likely to suffer cardiovascular disease. The olive oil might be a marker of wellness; it’s not a maker of wellness. There is likely a vitamin D confounder too. Olive oil consumption will be higher in Mediterranean countries where it is more affordable and traditional to local cuisine. Vitamin D intake will be higher in Mediterranean countries. Again – the olive oil might be a marker of something healthy, not a maker of health.
When to use olive oil
Extra Virgin Olive Oil (EVOO) is OK to use in the following circumstances:
i) As a salad dressing
My favourite salad dressing is EVOO and balsamic vinegar. I know that the EVOO has brought nothing much in the way of nutrition to the salad. It just tastes nice – especially when combined with balsamic. It would be easy to consume a tablespoon or two of EVOO on a ‘super salad’. That could be 120 to 240 calories. I don’t worry about calories in terms of weight, but they are a useful comparator for ‘nutrition bang for the buck.’ If I consume 250 calories from EVOO, I get next to no nutrition. If I consume 250 calories from (say) tinned sardines, the nutrition value would be far, far superior.
The simplest mayonnaise recipe uses egg yolks, mustard, EVOO, and vinegar or lemon juice. This could also be used for tuna-mayo and so a salad style dressing using EVOO can have other uses.
ii) When stir frying vegetables
In this post from 2016, I suggested renaming fats to call saturated fat “stable fat”, monounsaturated fat “monounstable fat” and polyunsaturated fat “polyunstable fat” (Ref 22). When we cook, i.e. heat substances to high temperatures, we want the compounds to be as stable as possible. Saturated fats are the most stable. They don’t mutate at high temperatures, next most stable are monounsaturated fats and polyunsaturated fats are the least stable.
As you can see with the olive oil nutrition data, olive oil contains more monounsaturated fat than the other two fats, but it still contains the other two fats. Coconut oil is mostly saturated fat (Ref 23). Sunflower oil is mostly monounsaturated fat, but it does have more polyunsaturated fat than olive oil making a larger part of this oil unstable (Ref 24).
Butter is not a pure fat – it contains some water and some protein, but it has a higher proportion of saturated fat than olive oil making it more stable (Ref 25).
Hence the most stable options for stir frying vegetables are butter or coconut oil, but both can change the taste of vegetables. Andy (hubby) cooks left over vegetables in butter to make “bubble and squeak.” Coconut oil might work for Thai-style stir fry vegetables, but coconut oil might overpower vegetables in other circumstances. Olive oil is thus the next best option for stir frying vegetables.
iii) As a base in sauces
The famous “Sofrito” Mediterranean sauce featured in the PREDIMED diet is made with tomato and onion, leek or garlic and EVOO. This sauce might be added to meat balls or used as a pasta sauce. This is also an acceptable use for EVOO, just not one that we use in our household (not being pasta consumers and being people who don’t put tomato sauce on meat).
Hence feel free to use EVOO in salad dressing, stir fries and sauces. But don’t ever think of it as a super food because it isn’t. You get a couple of nutrients for a lot of calories and a lot of money. There are better, cheaper, less calorific sources of those nutrients. Health claims made for olive oil are likely because olive oil is well marketed. The health claims don’t stack up. I didn’t know before writing this that our olive oil may not even be olive oil and the Mafia might have something to do with this (Ref 26). That could explain a lot!
References
Ref 1: @MsGlynisBarber and https://agelessbyglynisbarber.com/
Ref 2: https://agelessbyglynisbarber.com/diary-entries/how-nutritious-are-vegetables-really/
Ref 3: https://www.zoeharcombe.com/2018/01/saturated-fat/
Ref 4: https://www.zoeharcombe.com/2015/05/food-groups/
Ref 5: https://fdc.nal.usda.gov/fdc-app.html#/food-details/171413/nutrients
Ref 6: https://fdc.nal.usda.gov/fdc-app.html#/food-details/170562/nutrients
Ref 7: https://fdc.nal.usda.gov/fdc-app.html#/food-details/168421/nutrients
Ref 8: https://fdc.nal.usda.gov/fdc-app.html#/food-details/2345616/nutrients
Ref 9: https://twitter.com/AlpacaAurelius/status/1762249622175502383
Ref 10: https://www.tesco.com/groceries/en-GB/products/279751582
Ref 11: https://www.forbes.com/sites/ceciliarodriguez/2016/02/10/the-olive-oil-scam-if-80-is-fake-why-do-you-keep-buying-it/
Ref 12: https://www.foodsafetynews.com/2023/12/spanish-and-italian-investigators-uncover-olive-oil-fraud/
Ref 13: https://www.healthline.com/nutrition/11-proven-benefits-of-olive-oil
Ref 14: https://fdc.nal.usda.gov/fdc-app.html#/food-details/169429/nutrients(remember food databases don’t add up precisely).
Ref 15: https://superfoodly.com/orac-value/olive-oil-extra-virgin/
Ref 16: https://superfoodly.com/orac-value/arabica-coffee/
Ref 17: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5877547/
Ref 18: https://www.webmd.com/diet/foods-high-in-polyphenols
Ref 19: Harcombe & Baker. Plant sterols lower cholesterol but increase risk for coronary heart disease. Journal of biological sciences. 2014.https://thescipub.com/abstract/ojbsci.2014.167.169
Ref 20: https://www.bmj.com/sites/default/files/attachments/bmj-article/pre-pub-history/Original%20article%2020.6.18.pdf
Ref 21: https://www.zoeharcombe.com/2017/09/predimed-the-mediterranean-diet
https://www.dietandhealthtoday.com/2017/09/the-mediterranean-diet-nuts-olive-oil-and-that-predimed-study/
Ref 22: https://www.zoeharcombe.com/2016/05/types-of-fat/
Ref 23: https://fdc.nal.usda.gov/fdc-app.html#/food-details/330458/nutrients
Ref 24: https://fdc.nal.usda.gov/fdc-app.html#/food-details/1750349/nutrients
Ref 25: https://fdc.nal.usda.gov/fdc-app.html#/food-details/789828/nutrients
Ref 26: https://bangersandballs.co/debunking-myths/olive-oil-and-the-mafia/
