Vegetable Oils Are Dangerous to Health

vegetable oil

For many decades, health authorities have extolled the alleged virtues of vegetable oils, at the same time that they’ve been denigrating meat. Vegetable oils, they tell us, are full of “healthy” polyunsaturated fat, unlike meat, full of allegedly artery-clogging saturated fat. In reality, vegetable oils are dangerous to health, and furthermore, they’re not even really vegetable oils, but industrial seed oils.

What are vegetable oils?

To understand why vegetable oils are dangerous to health, we need to understand what they are. The term “vegetable” is a misnomer in this case and implies a degree of health and safety that they simply don’t have. How could something made of “vegetables” be unhealthy?

Common vegetable oils include the following:

  • corn
  • soybean
  • canola
  • sunflower
  • peanut
  • cottonseed
  • safflower

These oils have a few things in common. One is that they have only been in use for a short while in terms of human history, since the technology to extract these oils didn’t exist until the 19th century. Two, they come from sources that are intrinsically low in oil (except for peanut oil), which explains why they were not used, or even for the most part why they didn’t even exist, until recently.

Vegetable oils are better called industrial seed oils, since they’re made from seeds, not vegetables, and require an industrial process to make them in any volume. Oils that people have commonly used for a long time, such as olive oil, are not industrial seed oils and come from, in the case of olive oil, a fruit with a high fat content the oils of which are relatively easily extracted.

The manufacturing process for vegetable oils involves pressing at high pressure, and extracting more oil using solvents such as hexane, a volatile hydrocarbon similar to gasoline. The oils are then refined by heating to a high temperature and adding sodium hydroxide (lye), and finally, degummed, bleached, and deodorized.

Without knowing anything else about it, I already know that I don’t want this industrial substance in my body, much less in the massive quantities most people consume.

Chemically, vegetable oils are characterized by a high amount of polyunsaturated fats; for example, corn oil contains about

  •  saturated fat, 13%
  • monounsaturated fat, 28%
  • polyunsaturated fat, 55%
  • trans fats, 0.3%

In this case, the polyunsaturated fats and trans fats are the most health-damaging, because they are almost entirely composed of omega-6 fatty acids.

While omega-6 fatty acids are not intrinsically dangerous, the dose makes the poison, and virtually everyone in the Western world consumes far too much of these. An unbalanced ratio of omega-6 to omega-3 fatty acids contributes to a multitude of the diseases of civilization, including cancer, heart disease, and diabetes. While people living in a more natural state and eating whole, unprocessed foods may ingest a ratio of omega-6 to omega-3 fats of 2:1 or even 1:1, ratios in the modern world are typically over 15:1 and even up to 50:1.

Industrial seed oils are behind much of our modern epidemic of the diseases of civilization.

Vegetable oils may cause heart disease and raise death rates

The lipid hypothesis of heart disease, sometimes called the diet-heart hypothesis, holds that dietary saturated fat and high blood cholesterol cause coronary heart disease. Since the beginnings of that idea, mainstream health authorities have urged people to use vegetable oils in order to replace saturated fat with polyunsaturated fat, in the hope that this would reduce the incidence of heart disease. How has that worked out?

A recently published re-analysis of data from the Minnesota Coronary Experiment found that polyunsaturated fats did indeed lower serum cholesterol. Problem is, each 30 mg/dL reduction in cholesterol was associated with a 22% increased risk of death.

The same group re-analyzed the data from the Sydney Diet Heart Study and found that the intervention group that had replaced saturated fat with vegetable oils had a death rate from all causes that was 62% higher than the control group, and 70% higher for cardiovascular disease.

These were randomized controlled studies, which can show causation, as opposed to epidemiological studies, which cannot, and only show association. In epidemiological studies that show an association between intake of polyunsaturated fats and less heart disease, that association could very well be due to the healthy user effect.

Knowing this, deliberately consuming more polyunsaturated fats in the form of industrial seed oils seems positively dangerous to health.

Vegetable oils cause cancer

In animal experiments it’s long been known that corn oil reliably increases cancer rates. For example, mice that were fed a diet high in corn oil had double the incidence of cancer.

Dietary corn oil promotes tumors in rats by impeding apoptosis, or programmed cell suicide, in cancer cells.

In humans, we have the Israeli paradox.

Diet and disease–the Israeli paradox: possible dangers of a high omega-6 polyunsaturated fatty acid diet

Israel has one of the highest dietary polyunsaturated/saturated fat ratios in the world; the consumption of omega-6 polyunsaturated fatty acids (PUFA) is about 8% higher than in the USA, and 10-12% higher than in most European countries. In fact, Israeli Jews may be regarded as a population-based dietary experiment of the effect of a high omega-6 PUFA diet, a diet that until recently was widely recommended. Despite such national habits, there is paradoxically a high prevalence of cardiovascular diseases, hypertension, non-insulin-dependent diabetes mellitus and obesity-all diseases that are associated with hyperinsulinemia (HI) and insulin resistance (IR), and grouped together as the insulin resistance syndrome or syndrome X. There is also an increased cancer incidence and mortality rate, especially in women, compared with western countries. Studies suggest that high omega-6 linoleic acid consumption might aggravate HI and IR, in addition to being a substrate for lipid peroxidation and free radical formation. Thus, rather than being beneficial, high omega-6 PUFA diets may have some long-term side effects, within the cluster of hyperinsulinemia, atherosclerosis and tumorigenesis.

For health authorities, a paradox is a situation in which their cherished beliefs are contradicted by data. In this case, the “paradox” is easily resolved: vegetable oils can kill you.

Vegetable oils cause liver damage

Excessive alcohol intake is well known to cause liver damage and cirrhosis. What’s less known is that, in experimental animals, alcohol alone won’t cause liver damage. Something else is required, and one of those things is linoleic acid, the main polyunsaturated fatty acid found in vegetable oils. Dietary linoleic acid is required for development of experimentally induced alcoholic liver injury. Animals that were fed tallow and given high amounts of alcohol showed no liver damage. Beef fat prevents alcoholic liver disease in rats.

Non-alcoholic fatty liver disease (NAFLD) is strongly associated with obesity and insulin resistance, and has been increasing by leaps and bounds. Humans with NAFLD have a higher ratio of omega-6 to omega-3 polyunsaturated fats in their livers, which is the result of high consumption of omega-6 fats and low consumption of omega-3 fats.

Coinciding with the increased consumption of vegetable oils over the past few decades, not only has there been an increase in NAFLD, but other inflammatory conditions, such as cardiovascular disease, obesity, inflammatory bowel disease, rheumatoid arthritis, and Alzheimer’s disease.

How do industrial seed oils manage to cause all these diseases? To my mind, one of the most important factors may be that they rapidly induce damage to mitochondria, the powerhouses of cells. They also increase the release of inflammatory cytokines.

Processed foods are loaded with industrial seed oils

Here’s the ingredient label from a bottle (plastic of course) of salad dressing. The most abundant ingredient is vegetable oil, and you don’t even know whether it’s soybean or canola oil, not that it makes a lot of difference. Also note high-fructose corn syrup, sugar, and various chemical ingredients. Now, go ahead and pour this concoction on your healthy salad, as millions do, and you’ve just made it unhealthy.

Image result for corn chips ingredients label

Corn chips: second ingredient is vegetable oil.

Fast food is cooked in vegetable oils. In general, almost any can or bag of processed food you look at lists vegetable oil as an ingredient.

Conclusion / Solution

As we’ve seen above, vegetable oils, aka industrial seed oils, can cause heart disease, cancer, and a host of other maladies.

And, in general, food companies have contaminated a whole host of foods with the stuff. What’s the answer? How can we avoid this garbage “food”?

Eat whole, unprocessed food. That means meat, fish, dairy products, fruits and vegetables, nuts. Don’t eat anything that comes in a manufactured bag or box, or anything that has been through an industrial process.

If you need oil for salads or other foods, use olive oil, a healthy fat that has been used for thousands of years.

However, for cooking at higher heat, use lard, tallow, butter, ghee, or coconut oil. Make sure these are pure and not hydrogenated.

PS: If you need to lose weight and you want to save yourself years of poor results due to bad information, I’ve put everything in a simple guide for you.

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  1. Matevž says:

    Nice article, as always!

    Slight typo: “Do understand why vegetable oils…”

  2. Bill says:

    Full of good information clearly expressed as usual PD.
    Again Thanks !

  3. Thomas says:

    I’d been ignoring my liquid condiments up until now, just never thought of it. After looking at the back of each jar, they’re almost all gone now. Well, fortunately, things like Caesar dressing have been around for a long time, and hopefully can be made healthily from scratch.

  4. Bill says:

    PD, slightly off topic but very relavant & interesting. Credit Swiss Bank has issued a report for it’s investors on the health affects of industrial oils and carbs. Written with a view to advising what will be growing markets in the future an what will decline.

    Dr Malcolm Kendrick in the UK commenst on this issue here :

    • Nick says:

      Yeah, those fad-following Swiss bankers! That’s pretty amazing. It’s nearly 2 years old, is there any update to report, I wonder?

      • Bill says:

        Yes Nick, almost 2 years old and I had not heard a whisper about till today when I found that post by Dr Malcolm Kendrick.

        The report is predicting out to 2030 which is still a good ways off.

        I suspect it’s being an international bank which is the ‘reason’ why Credit Swisse published this report. They want & need to know what businesses will thrive or not thrive, in the future in order to know what investments and loans etc, will be best.

        On the basis of that report I suspect they may have moved their investment portfolio away from Pharmaceutical companies selling statins and away from loans to grain companies…

  5. Ole says:

    It is the slow poisoning of an entire global population. So sad….

  6. Nick says:

    Another interesting article, thanks Dennis. My dear mother got us on margarine in the 70’s, not because of supposed health concerns, but because it was CHEAPER than butter. My dad never liked it and continued using butter, but I developed a taste for it, and used it into my adulthood in lieu of butter. My wife also developed a taste for it somehow, and so we used it together.

    Now we’re off it and on to proper butter, but we hardly ever use it, since we’re off toast. And I was never one to use it on bread much, at least living here in Germany these last dozen years, the bread capital of the world. I would always say that the bread’s so good here it doesn’t need butter. Now, when I have an occasional nibble of it, it’s as a butter or fat / sauce delivery vehicle.

    My sister & I also grew up on corn oil at home. Again for the same reason: Mom grew up extremely frugally, a post-depression farm girl. Wonder how much damage that all did.

  7. Peter says:

    Fantastic article, I am a medical student and they definitely don’t teach this in class so I guess I will teach it myself.

    People like you are why I am still confident that we can get the right information to the right people who need it. We need young men who are fit, healthy and full of testosterone.

  8. Chris in Minneapolis says:

    Absolutely. Simple dressings can be made very quickly from olive oil, vinegar and whatever spices you would like to add. Homemade dressings taste far better than the processed junk.

    Most “health store” dressings are also full of bad oil…but it’s organic!!

  9. ConantheContrarian says:

    Is palm oil bad? At one time in my life, I was allergic to dairy products, so I swore off butter and used “healthy” margarines as a substitute. Although my allergy has almost disappeared, I still like to use margarine. Is Palm Oil bad too. I notice that it is not on the list above, so I thought that I would ask.

    • P. D. Mangan says:

      Hi Conan – Although I’ve read bad things about palm oil, it contains only 9% omega-6 polyunsaturated fats, which makes it healthy in my book.

      • ConantheContrarian says:

        What about grape seed oil. Because it comes from a seed, is it processed the same way as the other industrial oils?

        • P. D. Mangan says:

          Turns out, to my surprise, that grape seed oil is not so healthy. It is, in fact, an industrial seed oil.

          • ConantheContrarian says:

            I was looking at the ingredients of some food — I cannot remember what it was — and I saw that the product had expeller pressed safflower oil. So if it is expeller pressed, it might be good, but then the omega fats come into play. What is the verdict on that situation?

          • P. D. Mangan says:

            No, expeller pressed won’t make much difference because the main issue is the omega-6 fats in the oil itself.

  10. guest says:

    Economist Karl Denninger also noted:

    “There are no good “vegetable” oils. Some are worse than others but none are good. Some nut based oils (e.g. coconut) are perhaps better, but were talking in relative terms, not absolutes. Unsaturated oils are not shelf-stable without chemical modification — that’s what “unsaturated” means, that there are open chemical bond sites on the hydrocarbon chain. Hydrogenated oils (if that word appears anywhere on the label) are trans-fats and the safe amount of them in your diet is zero. All plant-based oils are high in Omega-6 and while you do need some small amount of them in their natural form they are pro-inflammatory and thus promote heart disease. Note that historically the balance of Omega-3 (mostly in animal flesh) and Omega-6 (mostly in plants) was about 1:1. Concentrating the amount of Omega-6 oils by processing plants into oils has dramatically increased the ratio to, in most people, 10:1 or more!

    The pharmaceutical industry is well aware of point this and has been for decades. In fact all of the OTC NSAIDS (Ibuprofin, aspirin, etc) work by reducing the metabolism of Omega-6 fatty acids into inflammatory compounds.

    Let that sink in for a minute or two: Both your doctor and the pharmaceutical industry know, as a matter of scientific fact, that consuming these oils fuels inflammation because the method of action of some of the most-widely used over-the-counter drugs is to reduce that metabolic process.”

    That’s why aspirin helps!

    And theres more:

    “Alarmingly, an assessment of industry-sponsored RCTs showed the median increase in life expectancy for selected participants in secondary prevention trials who adhered to taking statins every day for several years was a mere four days.”

    From The cholesterol and calorie hypotheses are both dead — it is time to focus on the real culprit: insulin resistance

    Again found via the Market Ticker, where Karl Denninger further adds:

    “Now tell me folks — would you agree to take a drug after a heart attack if (1) you knew it would cost you some amount of money — any amount of money — and (2) that the expected improvement in your survival time was four days if you took it every day for several years?

    No, you would not — and you know it.

    Yet not only the drug industry but your doctor have made billions of dollars selling you these drugs without telling you that the expected improvement in your life is four whole ****ing days.

    Knowingly failing to disclose a material fact that would have changed your decision had you known it for the purpose of making a profit at your expense has a name: FRAUD. It is not a mistake, it is a crime.”

  11. Daniel Antinora says:

    “While omega-6 fatty acids are not intrinsically dangerous, the dose makes the poison, and virtually everyone in the Western world consumes far too much of these. An unbalanced ratio of omega-6 to omega-3 fatty acids contributes to a multitude of the diseases of civilization, including cancer, heart disease, and diabetes. While people living in a more natural state and eating whole, unprocessed foods may ingest a ratio of omega-6 to omega-3 fats of 2:1 or even 1:1, ratios in the modern world are typically over 15:1 and even up to 50:1.”

    So… Since I’m a hard gainer and it’s hard for me to sit 30-40lbs above my natural weight like I like to do…

    Let’s just say I have to eat a lot of junk food (burgers and fries can get me the 4,000 calories a day I need)….

    If I just down enough fish oil and check my levels (assuming it’s actually the ratio that’s the problem) I’m good right? I have to make a tradeoff somewhere because I just can’t force myself to enough clean food to get the necessary calorie intake.

    • P. D. Mangan says:

      Hi Daniel – Fish oil can partially mitigate a high consumption of omega-6 fatty acids. An article, Healthy intakes of n−3 and n−6 fatty acids: estimations considering worldwide diversity, states:

      With caveats inherent for ecologic, nutrient disappearance analyses, a healthy dietary allowance for n−3 LCFAs for current US diets was estimated at 3.5 g/d for a 2000-kcal diet. This allowance for n−3 LCFAs can likely be reduced to one-tenth of that amount by consuming fewer n−6 fats.

      So, given average US consumption of omega-6 fats, 3.5 g/d of omega-3 fats is a healthy level. That’s a lot, something like equivalent to 3 tsp of cod liver oil (which is about what I take in a week). If someone ingests little omega-6, then only a tenth that amount is needed, which is why I say that reducing the amount of omega-6 is the most important thing to do.

  12. Jimmy says:

    The oils you mention as safe tend to have a strong flavor, so not always so desirable in cooking. What other oils are safe? Avocado? Nut oils? Also how does cooking affect the safety of oils?

    • P. D. Mangan says:

      Avocado oil is safe. Nut oils like walnut oil have fairly high levels of omega-6. Extra light olive oil, which is to say, not extra virgin olive oil, is lighter in taste and may be useful in cooking.

  13. R. says:

    What about olive oil made from pomace?

    • P. D. Mangan says:

      Afraid I don’t know anything about that. Olive oil generally is good.

      • R. says:

        I looked it up in the meantime. Not sure what it is chemically, but it’s extracted the same way most oils mentioned in this post are, through use of solvents and heating.

        There were some recalls and bans at times, as incorrect refining can introduce toxic substances food safety agencies pay close attention to.

        • Bill says:

          R, I had never heard of pomace oil. But there you are. That’s your answer. Industrial oils are new and not made in people friendly ways, using toxic chemicals. They are cheap & nasty.

  14. oil boy says:

    I just reread this and the part about liver disease blew my mind! Tallow versus linoleic acid. I notice there are two listings on wiki’s vegetable oils table I guess omega 3 and 6 versions. What’s going on there?

    I see that avocado oil is another option, especially for cooking because of its high smoke point and that it’s extracted from the fruit not chemically pulled out of parts of the fruit that don’t have no business being extracted from.

    I guess us alcoholics need to find good oils.

  15. eah says:

    “If you need oil for salads or other foods, use olive oil,…”

    For salads I make what I consider to be a classic vinaigrette: two parts olive oil, one half part rapeseed oil, one half part linseed oil (better omega 3/omega 6 ratio), one part vinegar, plus salt, pepper, and simple prepared mustard to taste.

  16. James says:

    I believe this article is mostly correct. However, cold-pressed sunflower oil may be OK when in combination with other oils according to this article:
    on Parent Essential Oils by Dr. Robert Rowen and his wife who is also an MD

  17. James says:

    Someone wrote about rapeseed oil, also known as canola oil. Canola oil is not good for brain health. See

  18. Q says:

    Thank you for the article.

    How bad is peanut oil compared w canola? Is it made via roughly the same process?

    • P. D. Mangan says:

      Good question. Peanut oil is high in omega-6, but since it’s naturally high, may not require the extensive processing that seed oils need. Canola oil appears to have other bad qualities besides high o-6. If I had to choose, peanut would be better. But you’d be better off with animal fats or olive and coconut oils.

  19. rowie says:

    lol, sodium benzoate in a salad dressing…
    In my country we have a producer of saladspreads for your sandwich, they also contain sodium benzoate, after contacting them, never heard from them again.

  20. Michael says:

    Hi Dennis,

    The article makes me wonder. If trans fats and vegetable oils are bad for health, then what about fully hydrogenated oils? If the problem is with the trans configuration of the fatty acids, then it’s not in fully hydrogenated oils (they are 100% saturated fat). If it’s because vegetable oils are bad for cooking at high heats (easy oxidation) or because they have high ratios of n-6 fatty acids which mess up the n-6/n-3 fatty acid ratio, well they don’t matter there either because fully hydrogenated -> 100% saturated fat.

    What do you think of this logic? What am I missing?



    • P. D. Mangan says:

      Fully hydrogenated means 100 percent of the oils/fats in a mixture are hydrogenated. They’re still trans fats. So, it’s a different issue from veg oils, which cause problems through aldehyde formation in cooking (HNE) and through an unbalanced o-6/3 ratio.

      • Michael says:


        Thank you for the prompt reply as well as addressing my points! I thought trans fats were unsaturated fatty acids that had carbon – carbon double bonds in the trans configuration (check out this article,

        Some folks say that these fully hydrogenated oils (which become saturated fats) are “bad” for precisely the same reason that saturated fats are bad (check this one out for example, But, if we don’t buy that saturated fats are bad, then in what other way are fully hydrogenated oils still harmful? They are chemically equivalent in fatty acid composition, in the sense of being composed of fatty acids with no carbon – carbon double bonds (for example, linoleic acid fully hydrogenated is stearic acid). I don’t see any pitfall, but was wondering if there was something I am missing.

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  22. Jodie says:

    Excellent article & enlightening comments! Thank you!

    As a former Certified Personal Fitness Trainer & a Certified Rehabilitation Fitness Therapist who taught others how to be healthy through good nutrition & exercise, never in my life did I ever think that I would end up with liver issues after eating seed & vegetable oils nearly daily for 3 years.

    That said, I now know first hand the dangers of eating seed (Sesame, Sunflower, etc.) & vegetable (Canola – which causes my hip to freeze & Arthrtis in my fingers & hands, Corn, Safflower, Soy. etc.) oils & I am now warning & educating everyone I know & meet. Yes, unfortunately, even some raw Organics can be harmful.

    Here is my story:

    I thought these oils were healthy, especially because I only bought organic oils, so every night I put them on my huge organic salads as a delish home-made salad dressing with organic lemon juice & Apple Cider Vinegar thinking it was healthy. Ha! Boy, was I wrong!

    They fooled me big time just like they are fooling the masses about medications like one of your Commentators stated. This Commentator also stated in so many words, that it’s all about profit & greed, not consumer safety. I agree 100%.

    The result of my uniformed ignorance? For the past over 10 mths. I have had pain & swelling in my liver area. Over 11 mths. ago I also came down with a bad case of Shingles & now have post- Shingles nerve pain. Research shows that sometimes Shingles & Liver issues can go hand-in-hand. One can cause the other.

    Some of my symptoms were in the beginning: I could not drive over speed bumps or pot holes without crying out & I didn’t feel like being sociable which was out of my character.

    Furthermore, during the 1st 2 mths. I could not walk or eat solids, except lettuce, raw veggies, & wild-caught Alaskan Salmon which is full of inflammation-fighting Omega 3’s.

    In addition, after about 4-5 mths., I suddenly lost 50 lbs. in 5 mths. due to being on an unintentional very low calorie ‘diet’. Unfortunately, I became Anorexic & very weak with no muscle or fat. I was all skin & bones and looked & felt horrible. When I looked in the mirror I would cry. I didn’t look like me anymore.

    Now for the good news! A little over a month ago I was finally able to eat meat (dairy, lean chicken & turkey, as well as some fruits, except for citrus fruits ) & started forcing myself to eat even though I knew it would cause worse pain. But, like a Trooper, I perservered!

    I was finally able to add Probiotics to my diet & that seemed to help a little although I could not eat or drink any Probiotics for the first 9 mths. or so.

    I am happy to say that I have now put on 4-5 lbs. & look & feel better, but am trying to put on another 3-5 lbs., so I can start doing cardio again. Weights unfortunately cause me more pain. Therefore, I look forward to that in the future after my body heals naturally the way it was designed to do.

    I eat often & a lot, whereas before I got ill, I could fast almost a whole day w/o a problem & still feel good.

    Today, if I eat anything with seed or vegetable oils,
    saturated fats, or even iodized salt my liver still swells up & I have more pain. However, I have conditioned myself to stay away from anything fried, although surprisingly stir fried foods or most Asian foods do not hurt me.

    The only oils that I can consume are Org. Avocado Oil, Org. Coconut Oil, & Org. Olive Oil, but I can only eat very little each time. Be careful though guys, companies are fooling consumers by not telling them if they cut their oils with cheaper seed & vegetable oils. Organized criminals are being arrested all over the world for scamming consumers like this.

    Therefore, my wise advice to you would be to only buy pure organic oils that are certified as pure. This means they will contain a seal & must state on the label where the oil comes from (Italy, CA, etc.). If you go into the internet you will find a list of the names of certified brands to help you choose & test the best ones for you & your family.

    Lastly, what I want to say to you all as a form of encouragement is that if you are experiencing something similar to what I have been:

    (1.) Know that it may take time to heal your body….be patient…the liver is a very resilient organ.

    If it took 3 years for mine to get sick; therefore, it may take 3 years for it to completely heal.

    (2.) Take one baby step at a time.

    (3.) Test certain foods & incorporate the ones you can tolerate slowly &

    (4.) Remember, everybody’s body is different. It may take a shorter or longer time to heal.

    For instance, I have a friend with similiar GI Tract problems & she could eat Chicken with fat on bones broth/stew when she first got sick, but when I tried eating it in the beginning it made me itch all over which is one of the signs that your liver isn’t detoxifying correctly. Now, I can eat meat (except for beef & pork) w/o any skin or fat.

    Hope this helps!

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