best natural foods

Polyunsaturated fat - more harm than good

Polyunsaturated fat is almost universally believed to be good for health. Almost all doctors, nutritionists, dieticians and other health authorities recommend that we use vegetable oils - such as corn, soybean, sunflower, safflower - that are high in polyunsaturated fat.

This advice arose from the widespread belief that saturated fats and cholesterol cause heart disease, which is not true and not backed by scientific studies.

Yes some scientific studies show that people who eat large amounts of saturated fat – like animal fat and coconut oil – tend to have heart disease.

At the same time, other scientific studies show that people who eat large amounts of saturated fats do not develop heart disease.

The most famous example are the French, who love of rich foods and yet they have relatively low rates of heart disease – much lower than that of Americans.

The people of Okinawa, famous for the good health and longevity, also eat large amounts of saturated fat. They cook mainly with pork lard! And some of their popular traditional dishes are stewed pork legs, containing plenty of saturated fat.

Historical trends

Throughout history, almost all people all over the world use saturated fats as their main fat for cooking – butter in Europe, ghee in Northern India, pork lard in China, beef tallow in America, coconut and palm oil in the tropics.

Traditionally, polyunsaturated fat has never been used for cooking. Some European cultures took products like flaxseed oil, which are rich in polyunsaturated fatty acids. But they took them in salads, not as cooking oils.

And throughout history, people have been generally free of heart disease. In America, the rate of heart disease began to climb only after the 1920s. In most other parts of the world, the rate of heart disease escalated more recently, after the 1960s or even 1970s.

Accounts given by some older heart disease specialists are telling. One doctor recalled how, when he was a medical student in the 1920s, heart disease was so rare that when one case appeared, the professor insisted that the entire medical school should view it, as they never get the chance to see another case again.

Then there is the story about the American doctor who tried to introduce the electro cardiogram (ECG) machine for monotoring the heart, which was invented by a German. He was advised by his colleagues to look for better ways to earn a living.

Now comes the surprising part... If you look at history, you will also discover that heart disease began to increase AFTER people started to switch to using polyunsaturated fat, such as vegetable oils.

In America, this began during the great depression of the 1920s. People were poor and they started to switch to eating margarine instead of butter, since margarine was cheaper. That was when heart disease and other health problems started to appear.

Then came the studies by Dr Ancel Keys during the 1950s, which "proved" that saturated fats caused heart disease. For decades, his findings were accepted as gospel truth. But in recent years, some scientists looked more closely at the original data of Dr Ancel Keys and they discovered that he had "cheated" - he highlighted data that showed saturated fat to be harmful and ignored data that showed saturated fat produced no harm.

In the 1980s, American soybean oil and corn oil producers waged a massive campaign to convince the world that saturated fats - particularly tropical oils like coconut and palm oil - are harmful and to promote their vegetable oils. They succeeded to a large extent and most people today believe that polyunsaturated fat is healthy - thanks to the massive campaigning of American vegetable oil producers.

But have you noticed? The campaign has since switched focus to monounsaturated fats. And now the new "healthy oil" that is being promoted is not corn, soybean, safflower or whatever, but canola oil.

Why the switch? Because by the 1980s, scientific evidence began to emerge that polyunsaturated fat is not all that healthy after all. We need to seriously reconsider our ideas about healthy cooking oils.


As pointed out in the introductory article about healthy cooking oils, the main problem with polyunsaturated fats is that they turn rancid easily – when exposed to heat, light and air.

Depending on the type of oil, some turn rancid more easily than others. The extreme case would be flaxseed oil. It has to be kept in dark, totally light-proof bottles and perpetually refrigerated. Even then, tests have shown that many brands of flaxseed oils sold in health stores have some degree of rancidity.

Regular oils that are promoted as healthy cooking oils – like corn oil, soybean oil, etc – may not appear rancid. But that is because they have been deodorised to remove their rancid smells. These oils are, in fact, rancid before they even leave the factory. Because they are typically extracted using very high temperature (as well as harmful chemical solvents) that make them rancid.

They then undergo various treatments, including bleaching, the addition of anti-foaming agents, dedorisation, etc to make them appear good. But they are not. In fact, they are far, far from being healthy cooking oils.

If at all you wish to use polyunsaturated fat, make sure you buy cold-pressed oils. And use them mainly in salads or, at most, in low or medium heat cooking. Do not allow the oil to smoke. That's when it starts to turn rancid and harmful.

Trans fats

Yet another very serious problem with polyunsaturated fat is that they are often been turned from liquid oils into solid fats like hard margarine and vegetable shortening, or semi-solid grease like soft margarine.

This is a highly unnatural process, called hydrogenation, that involves the use of high heat, high pressure and toxic chemical catalysts. (Yes, the catalysts are later removed but tiny traces inevitably get left behind.) It leads to the formation of trans fats which are today known to be extremely harmful to health.

Countries like Denmark and US cities like New York have already banned the use of trans fats. Yet awareness about the harm of trans fats has only just begun and it will take many more years before people fully realise how harmful they are.

We are still at the stage where nutritionists and other so-called experts continue to recommend harmful products like margarine, just because they contain more polyunsaturated fat. You can learn more about trans fat from my Stop Trans Fat website.

Omega 6 : Omega 3

Meanwhile, you must have noticed the great emphasis on Omega 3 fatty acids these days. Yes, Omega 3 is good for health and yes, it is a form of polyunsaturated fat.

But it is not just a simple matter of Omega 3 is good, let's take more of it. The real issue is that people nowadays are taking far too much Omega 6 (another form of polyunsaturated fatty acid) and too little of Omega 3. It is the ratio of Omega 6 : Omega 3 that is important. A healthy ratio is said to be about 2:1. But for many people, the ratio is more like 20:1.

Why is this? On the one hand, modern farming techniques has reduced the amount of Omega 3 naturally found in food. For example, eggs are supposed to be naturally rich in Omega 3 - provided the eggs come from free-ranging chickens that eat a natural diet of insects, worms, etc. But modern eggs from factory farms contain very little Omega 3 and egg farmers are now trying to produce "Omega 3-rich eggs".

The other problem is, again, due to the widespread use of vegetable cooking oils as they are very high in Omega 6.

Cell wall structures

Yet another problem has to do with our cell wall structures. The walls of our body cells are made of largely saturated fats and cholesterol. We need saturated fats - and cholesterol - to maintain the integrity of our cell walls. When we take too much polyunsaturated fats, the cell walls weaken and our cells become more prone to virus attack. Learn more in the article about the benefits of saturated fats - not polyunsaturated fat.

The bottom line

The recommendation to take more polyunsaturated fat is supposed to help prevent heart disease. But the result is actually more heart disease, more cancer and more of other degenerative diseases.

It is not that polyunsaturated fatty acids are "bad" for health. They are good and they are important. Except that they have been used in the wrong way. Until about a hundred years ago, they had never been used as cooking oils. Traditionally, cooking oils had always been a combination of saturated fats (butter, lard, coconut oil etc) and monounsaturated fats (olive, sesame, peanut, etc).

The best way to take polyunsaturated fat is in natural food, eg in corn instead of corn oil, sunflower seed instead of sunflower seed oil, and so on. All plant products, as well as fish and seafood, contain polyunsaturated oils. You will be fine if you eat plenty of these.

Further reading

The subject of healthy cooking oils is a big and complex subject that cannot be covered in just one article like this. Please also read the following articles:

In addition, there are links the left of this page to discussions about some of the more common types of cooking oils, including both the unhealthy and healthy cooking oils.

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More sections to come
Natural Cancer Cures
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Stop Trans fats

Healthy cooking oils
Monounsaturated fats
Polyunsaturated fats - the dangers
Saturated fats - why they are not harmful
Saturated fats - health benefits
Saturated fats and heart disease I
Saturated fats and heart disease II
What is canola oil
Canola oil dangers
Duck fat
How to render duck fat
Choosing olive oils - what to look for
Extra virgin oilve oil / olive oil fraud
Olive oil health benefits
Olive oil types and grades
Olive pomace oil
Premium olive oils
Rapeseed = canola
Rice bran oil
Cooking with raw / toasted sesame oil
Sesame oil health benefits