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comparison of olive and vegetable oils

Comparison Of Oils In Mediterranean Diet And American Diet: Healthy or Unhealthy

One of the key differences between the Mediterranean diet and North American diets lies in the fats we eat. A comparison of oils in Mediterranean diet and American diet is shedding some light on why the olive oil from the Mediterranean is healthy and why the vegetable oils in North America may be unhealthy.

Types Of Oils We Consume

Mediterranean Region – The primary oil in the Mediterranean diet is the monounsaturated fatty acid rich olive oil. It is this oil that apparently imparts various health benefits among the people of the Mediterranean region. Consumption of this oil (not exceeding the daily recommended amounts of between 25-35%) even helps people lose weight or manage their weight.

North America – In North America, we mostly consume corn, Canola and soybean oils. All three have a low level of saturated fatty acids, various amounts of monounsaturated fatty acids and various composition of polyunsaturated fatty acids. Based of what you’ve learned from the dietary fats article, you would think it is a good thing.

In fact, many of our health and health friendly advocates, urge us to use Canola oil and soybean oil in our cooking and some “fat” experts even go as far as to suggest to take in a couple of teaspoons of the “healthy” Canola or soybean oils daily as a supplement. Even the notable Weight Watchers program suggests to eat two teaspoons of oils per day. One of the recommended “healthy oils” is Canola. Canola and soybean oil are also used in thousands of processed foods by food manufacturers.

Interestingly, we eat low-fat foods, we eat “healthy” oils, but unlike our Mediterranean cousins we are getting increasingly fatter and sicker.

 

I thought that to help me understand all this contradiction, a closer look and a comparison of oils in the two different diets will help. I was quite surprised at what I found. So much so, that I decided to share it with you.

Comparison Of Oils In Mediterranean & North American Diets

Previously I wrote an article on the types of dietary fats and the composition of the different fats. Please refer to those articles if you are not sure of some of the terminology.

To briefly review, there are 3 main types of naturally occurring fats:

  • saturated
  • monounsaturated
  • polyunsaturated (including essential fatty acids: omega-6 and omega-3)

For years now we have been told that the only good fats are monounsaturated and polyunsaturated fats. There is a lot of controversy about the “healthy/unhealthy” effects of saturated fats but for the sake of this article and because oils in the Mediterranean diet are not saturated we are not going to pay much attention to saturated fats.

So let’s have a look at fatty acid composition of olive oil (Meditteranean diet) and compare it to the three commonly used oils in North American diet: Canola, soybean and corn oil, .

Figure 1. Comparison of oils

GB Health Watch put together a table of the fatty acid components of major dietary oils. The table also includes the information related to olive oil, Canola oil, soybean oil and corn oil, the ones commonly used in the our diets.

fatty acid content in oils

image from: gbhealthwatch.com

For simplicity, I pulled the four oils in question and created a table that only compares those. The table below compares the fatty acid composition of the common oils in our diet (Canola, soybean and corn oil) and the fatty acid composition of the Mediterranean olive oil. A tablespoon of each oil (in grams) is compared.

Comparison Of Fatty Acid Content Of Olive, Canola, Soybean and Corn Oils

Table 1. Comparison of oils

Comparison of fats between Mediterranean and North American diets

So just to reiterate, there are 3 naturally occurring fats: saturated, monounsaturated and polyunsaturated. The polyunsaturated fats also contain the two essential acids we need for survival, namely omega-3 and omega-6 fatty acids.

In the discussion of omega-3 and omega-6 fatty acids I told you that centuries ago the omega-6 to omega-3 fatty acid ratio was roughly 1:1. This ratio is considered to be a healthy one by a number of nutrition specialists and scientists.(Ref) Currently, this ratio in a North American diet is very high and depending on the diet you eat it may vary anywhere from between 20:1 and 40:1.

It really does not matter whether the number is 20 or 40, in either case it is very high and possibly it is this skewed ratio that is causing havoc in our bodies and is responsible for increased levels of cardiovascular diseases, obesity, diabetes, high cholesterol levels, Alzheimer disease and a host of other diseases that we are seeing today.(Ref)

Table 1. compares the 4 main fatty acid components of these oils: saturated fatty acid, monounsaturated fatty acids, omega-6 and omega-3 fatty acids.

The fatty acid components seemed quite interesting.

  • Saturated Fats – All oils have very little saturated fats. There still is a lot of controversy surrounding saturated fats, but for the purpose of this explanation, let’s assume that it is a good thing or at least not a bad thing.
  • Monounsaturated Fats – With respect to monounsaturated both olive oil and Canola oil have a significantly large proportion of these fatty acids. On the other hand the monounsaturated fatty acid content of soybean oils and corn oil is very low. As a percentage of the 4 combined fats within the oils, this translates to roughly:
    • olive oil …………. 75%
    • Canola oil ………. 62%
    • soybean oil………25%
    • corn oil……………24%

    Olive oil and Canola oil contain the most monounsaturated fatty acids, about 75 percent and 62 percent, respectively.
    Soybean and corn oils contain significantly less monounsaturated fatty acids at only 25 percent and 24 percent, respectively.

  • Omega-3 Fatty Acids – All oils have a relatively low level of omega-3, with canola oil having the best value of 2.3 grams per tablespoon and olive oil the lowest or even negligible amounts. The relatively low levels of this fatty acid are not surprising because in nature omega-3 occurs in low levels in plants.
  • Omega-6 Fatty AcidsThis is where the surprise lies. Once again, olive oil and canola oil are very similar with relatively low levels. On the other hand, soybean and corn oils contain a significantly larger proportion of these fatty acids compared to other fats in their mix.
    • olive oil…………..8%
    • Canola oil………..21%
    • soybean oil………53%
    • corn oil……………57%

    Olive oil contains a relatively small amount of omega-6 fatty acids. Canola oil’s omega-6 levels are still fairly low at 21 percent. On the other hand, over half of the fatty acid content in soybean and corn oil is omega-6 fatty acids, 53 percent and 57 percent respectively.

The percentages of omega-6 fatty acids by themselves are not meaningful. Earlier I mentioned that the high ratio of omega-6 to omega-3 fatty acids in our diet appears to cause us health problems. In view of that, let’s have a look at the ratio of omega-6 to omega-3 in these different oils.

Ratio Of Omega-6 To Omega-3 Fatty Acids In The Oils Of North American Diet

I excluded the calculation of the ratio for olive oil because in olive oil the amount of omega-6 fatty acids is very small at only 8% and it adds very small amount of omega-6 to the overall diet. Because the levels of omega-3 are negligible, the ratio would not make sense. In the Mediterranean diet the small amount omega-6 fatty acid would be very well balanced by the high levels of omega-3 in the fish, the grass fed meat, the nuts and seeds the Mediterranean people consume.

  • olive oil………….not applicable
  • Canola oil……….2.2
  • soybean oil……..7.7
  • corn oil………….7.9

From this ratio you can clearly see that both soybean oil and corn oil are not acceptable as their ratio of omega-6 to omega-3 fatty acids is almost 8 times more than the healthy ratio of 1:1

Canola oil, although slightly elevated at 2.2 appears to best of the three North American oils.

Based on this analysis you would think that Canola oil could easily replace olive oil in our diets and impart similar health benefits as olive oil does.

Unfortunately, the story does not end here.

Why Canola Oil Is Not The Same As Olive Oil When It Come To Our Health

Canola oil is a controversial oil and many healthcare professionals believe that is not good for our health. Reading over some of the relevant publications(1, 2,), I tend to agree with that. There are several reasons why I say this:

  • Unlike olive oil Canola oil is not a natural oil in a true sense. Canola oil comes from rape seeds. Rape seed oil is high in monounsaturated fatty acids (which is good), but in a natural form it is also high in erucic acid which can cause health issues . To reduce the erucic acid in the oil, in 1995 the rape seeds were genetically modified and now the genetically modified seeds are used for the production of Canola oil. There is much concern about genetically modified foods with respect to our health(3, 4,).
  • Canola oil is partially hydrogenated. To process the oil it has to go through many manufacturing steps. During this process changes take place that make some of this oil hydrogenated. In other words, parts of this oil became trans fatty acids (really bad for your health). The Canadian government (where the canola oil comes from) maintains that trans level are only at 0.2 percent and are acceptable,however, the research done in the US has shown that the amount of trans fats may be as high as 4.6 percent. (1, 2).

 

Summary

Based on the comparison of oils in the Mediterranean diet and American diet, without a doubt, the olive oil comes out a winner. Right from the start that was a no-brainer. The surprising result made Canola oil a runner up. But given that Canola oil is genetically modified (GMO) and also the fact that processing turns some of the oil into trans fatty acids I strongly believe (and some other health advocates also believe) that you should stay away from it.

In my opinion, our only choice is genuine olive oil from regions (including the Mediterranean region) where we can be sure that olive oil comes from real olives.

I’d be curious to know what is your feeling on this topic as well as the topic of genetic modification of our foods. Please leave a comment.

 

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