Are You Eating Rancid Oils?

June 21, 2017

Are You Eating Rancid Oils - Dr.Axe

Rancid Oils

When most people think of cooking oils, what immediately comes to mind is vegetable or canola oil. These oils are found in abundance in the grocery stores because they are cheap to produce–due in part to the government subsidization of corn crops. But these oils, along with oils like soybean, cottonseed and safflower, are highly processed and rancid. I can’t encourage you strongly enough to remove them from your diet!

Processing Oils

Processed oils are extracted by high heat and pressure and the use of solvents. The fats in these oils are exposed to light and air, which oxidizes the fat (turns them rancid). The oil is then boiled to remove most of the solvent. The high heat and pressure destroy antioxidants and alter the chemical nature of the fat, creating dangerous free radicals. BHA and BHT, dangerous preservatives, are then often added to the oil to extend the shelf life.

Hydrogenization is similar to homogenization: it is the use of agitation and pressure to create creaminess in foods and prevent separation. It involves the addition of a hydrogen atom.



During hydrogenation, oils are turned into solid form for ease of use. Extracted oils are mixed with metal particles and treated with high-heat and pressure along with hydrogen gas. Emulsifiers are added to the mixture which is then steam-cleaned to remove rancid odors. It is then bleached and artificial dyes and flavorings are added.

Trans fats are found in partially hydrogenated fats and oils. They are dangerous because they are incorporated into the body’s cell membranes and interfere with normal cell metabolism and other chemical reactions.

Hydrogenated fats have been linked to:

  • Artherosclerosis
  • Birth defects
  • Bone and tendon problems
  • Cancer
  • Diabetes
  • Digestive disorders
  • Heart disease
  • Immune system impairment
  • Increased cholesterol levels
  • Learning disabilities
  • Liver problems
  • Low birth weights
  • Obesity
  • Reduced growth
  • Sexual dysfunction
  • Skin reactions
  • Sterility
  • Vision reduction

Better Oils to Consume

A much better option for cooking is unrefined coconut oil. This oil is far less processed and also has a higher heat threshold.

Many people will cook with olive oil, but this is still not your best option due to the lower heat threshold it has. Use olive oil in your salad dressings or other dishes that aren’t exposed to heat.

Animal fats and tropical oils, such as coconut oil, are forms of saturated fats. It has long been believed that saturated fats were behind high cholesterol levels and heart disease. In fact, research does not support this claim. Unsaturated fat makes up 74% of the fat that is found in clogged arteries, and more than half of that is polyunsaturated fat.

Many long-living cultures ingest large amounts of saturated fats which also contain many disease-fighting nutrients and phytonutrients. Mother’s breast milk is also high in saturated fats, which babies need for the development of their brain and nervous system.

Cold-pressed, minimally processed and unrefined plant oils are much safer choices than hydrogenated oils. After reading about the processing of oils, can you agree that those oils aren’t even real foods?


Weston A. Price Foundation (1999)

Dr. Mary G. Enig (2001)

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  1. Jonathon Willis on

    <p>What are your thoughts on cooking with organic pure butter? I’ve been using butter for cooking for the past 2 years and the benefits I’ve seen in my cholesterol numbers has been staggeringly good.</p>

  2. Dr. Axe on

    <p>Cooking with raw or organic butter is a great option. Coconut oil is probably my favorite, but I use butter occasionally as well.</p>

  3. Linda on

    <p>Where can grapeseed or coconut oil for cooking be found….WalMart, Kroger type stores or just health food stores like Whole Foods?</p>

  4. rosalind on

    <p>I know that coconut oil can be found at publix, kroger, and whole foods. It is with the oils. At kroger I found it in the organic section.</p>

  5. rosalind on

    <p>What about in baking what oil should you use. The coconut oil can get expensive. I haven’t looked at the grapeseed oil yet.</p>

    • Kevin on

      I get my Coconut Oil from The best deal I’ve found yet for every day cooking. A 54 oz. jar is just $20!! Order 2 and an additional 9 bucks worth and you get free shipping. Look for the NSI brand. =)

      For others, Costco has a 2 liter bottle of grape seed oil for $7.

  6. Christa on

    <p>You can buy grape seed oil or coconut oil on for really good prices, they have good cosmetic uses as well. Dr Axe, can you use olive oil to cook if you are careful not to use high heat? I usually don’t heat past 4 (out of 10) on my range. I just like the taste of olive oil and would prefer to use that if I can.<br/>Thanks!</p>

  7. Dr. Axe on

    <p>Hi Christa,<br/>Thanks for the link to the natural oils. You should be O.K. using Olive Oil on Medium/Low heat or below. The key is you don’t want it to start smoking.</p>

  8. Dr. Axe on

    <p>It’s hard to say with certainty because no real scientific research has been done on Canola Oil. However, 90% of Canola is highly processed. If you get a Cold Pressed Canola Oil it may be OK, but I would stick to the safe side and use Cold Pressed Olive Oil, Grapeseed Oil, or Coconut Oil instead.</p>

  9. Kieran on

    <p>I use coconut oil as it is the most stable oil as far as cooking is concerned and for some variety I use ghee which can also tolerate high temperatures unlike unsaturated oils. The mature coconut itself is great as a garnish. They should have some water in them when you shake the nuts but they are mature at the same time. You peel the husk off and hit it on the center with any heavy blunt instrument. collect and drink the water and grate the white meat which can be preserved in the deep freeze for a month at least. When you cook any vegetable, just before serving you sprinkle the grated coconut garnish on the vegetable which makes it tastier and aids digestion.</p>

  10. Jennifer on

    <p>Is sunflower oil an acceptable food? I have researched it, but have not been able to find anything trustworthy. Thank you.</p>

  11. Dr. Axe on

    <p>The problem with sunflower oil is that it is extremely high in Omega-6 fats and this will cause inflammation. But if you take an Omega-3 supplement and get sunflower oil cold pressed it’s probably not too bad.</p>

  12. Rosalind on

    <p>One more thing. Which Grapeseed Oil Product do you recommend? It looks like spectrum isn’t expeller or cold pressed. Thank you.</p>

  13. Dr. Axe on

    <p>Some peanut oil is rancid, but not all. It just needs to be unrefined. The downside of peanut oil is it’s high amount of Omega-6 fats that can throw off your Omega-3 balance.</p>

  14. Raine on

    <p>Lard, tallow (fat from beef), and bacon drippings from healthy animals raised on pasture are also fantastically healthy and delicious fats with which to cook. We use them regularly, as well as coconut oil, ghee, and butter. </p><p>I don’t use grapeseed oil for a lot of my cooking because its antioxidant content and other essential properties can be compromised with high heat cooking, and it also has a fairly high Omega 6 content as well. Grapeseed oil can go rancid just sitting on the shelf, should be refrigerated, and eaten on cold foods like salads.</p>

  15. Wanda on

    My daughter is going on the Ketogenic Diet for her seizures. The dietitian says NO coconut oil. Since 90% of the diet is fat (heavy cream, oil, butter, margarine) what oil would you suggest? They also say they would like us to use the margarine over the butter. What do you think? Because we are putting SO much fat into her, we want the BEST ones.

  16. Lisa on

    Dr. Axe,
    I’m surprised that you promote Grapeseed oil, since it is so high in Omega 6’s. For this reason, I don’t consider it a healthy option.

  17. Donna on

    I came across this article after doing a search on “Rancid Fats”. I decided to search after buying Kettle Chips Chili Lime cooked in 100% Avocado Oil. To me they smelled rancid though the Best Before date was Jan. 6, 2018. Has any one else experienced this rancid smell from these chips cooked in Avocado Oil. I guess the best way to avoid rancid fats is to avoid all so-called healthy processed foods cooked in most oils. I do buy my Flax Oil from Activation Products and as far as I know they aren’t rancid which is why they are more expensive than other healthy products. What about Red Palm oil that Nutiva sells? For the Blood Type “O” diet, I am suppose to avoid avocados and coconut, plus potatoes. I thought about trying Palm Oil.


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