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There are several popular restaurant chains that make it a point to tell customers that they use peanut oil for cooking and frying. The Five Guys burger chain and Chick-fil-A are two that quickly come to mind.
Is peanut oil really a healthier choice for cooking, especially when it comes to a fast-food type of joint? Chipotle, for example, uses rice bran oil instead. Before we delve into those issues, let’s take a look at the nutrition and fatty acid profile of peanut oil.
Peanut Oil History
Peanut oil is very mild tasting vegetable fat made from the oily, edible seed. Humans originally cultivated the peanut plant, a legume, in what is today Brazil or Peru at least as far back as 3,500 years ago.
Industrialized processing is not required to extract oil from peanuts. Thus, it is common in many cuisines of South American, African and Asian origin. Unrefined peanut oil is generally for cooking, with roasted versions used for flavoring much like toasted sesame oil.
Around the world, peanut oil is also known as groundnut oil or Arachis oil (after its biological classification Arachis hypogea). In the Deep South, locals sometimes used the term goober oil. Peanuts are commonly called goobers in that part of the United States, with boiled (peanuts) goobers a popular snack.
Historically, humans have used peanut oil for many other purposes besides food. During the Civil War, the Confederacy used peanut oil as an affordable lubricant for locomotives due to a shortage of whale oil. It had the distinct advantage of not gumming up the machinery. Housewives used it as an illuminant for lamps as well as a stand-in for lard during times of scarcity (1).
Nutritional Benefits of Peanut Oil
Examination of the nutritional profile of roasted and unrefined oils from peanuts indicates that it is somewhat similar to olive oil, canola oil, safflower oil and sunflower oil (high oleic). All are high in monounsaturated fats with some important differences for peanut oil.
Smoke Point
One of the best features of peanut oil is a high smoke point of 450°F / 232°C. Few unrefined fats are higher with the exception of ghee (485°F/ 252°C  and avocado oil (520°F/ 271°C). The attractively high smoke point makes peanut oil particularly suitable for frying foods.
Several refined oils have as high a smoke point as peanut oil. One of these that is widely used in the restaurant industry is soybean oil. However, the list of nourishing fats does not include highly refined and industrialized oils. As a result, we will exclude these factory fats from the discussion.
Fatty Acid Profile
The fatty acid breakdown of peanut oil is as follows (2):
- Monounsaturated (oleic acid, omega-9): 46%
- Polyunsaturated (linoleic acid, omega-6): 32%
- Saturated fat (stearic acid, palmitic acid, arachidic acid, behenic acid, lignoceric acid): 17%
Note that there are little to no omega-3 fats in peanut oil. Hence the ratio of omega-6 to omega-3 fatty acids is poor. In addition, there are scarcely any fat-soluble vitamins present unless Vitamin E is added to improve shelf life.
Thus, the primary benefits of peanut oil are due to its resistance to rancidity from heating.
The Problem with Polyunsaturated Linoleic Acid
Peanut oil is not as insanely high in rancidity prone, inflammation and obesity-inducing linoleic acid as grapeseed oil, hemp seed oil or pumpkin seed oil. This is good news.
The bad news is that the amount of omega-6 fats is high enough to be worrisome. It is fully 1/3 of the total oil, gram for gram, which is not a trivial amount. Within the context of the modern diet, this is especially problematic. Most people already consume far too many polyunsaturates on a daily basis.
Hence, consumers should use peanut oil with caution and sparingly if possible.
Certainly, for home cooking efforts, there are much better choices such as grass-fed butter, ghee, tallow, lard, coconut, red palm oil, and avocado oil. These are the only fats in my pantry and refrigerator. All are extremely low in omega-6, polyunsaturated fatty acids (less than 10%). Oil from peanuts contains over three times this amount!
Refined vs Unrefined Peanut Oil
Refined peanut (groundnut) oil, like all processed vegetable oil, is heavily refined, bleached and deodorized. Even when organic, smart consumers avoid refined oils. Processing heavily damages the fragile omega-6 fats resulting in free radicals. Since oil from peanuts is 1/3 polyunsaturate, this is a significant problem.
Unrefined peanut oil, on the other hand, is a much more informed choice. It is considered gourmet quality and can impart a wonderful flavor to dishes.
Notice the color of the unrefined peanut oil in the picture above. It is a rich copper color compared to the bleached and deodorized refined oils on either side of it.
Refining the peanut oil in the picture above would result in a pale yellow color too!
What type of oil do you think restaurants like Chick-fil-A and Five Guys use? Yep, you guessed it – the refined kind.
Peanut Oil Used in Restaurants
Choosing to eat at a restaurant that uses peanut oil for cooking is without a doubt a better choice than the typical chain using soybean oil. Not only is the soybean oil used highly refined and of GMO origin (translation: loaded with Roundup residue), it is also nearly twice as high polyunsaturates.
Even though a better choice, there are still concerns with peanut oil for cooking and frying. Consuming these foods regularly is not a good idea. Let’s explore why.
Monounsaturated and saturated fats in peanut oil are stable and don’t oxidize easily when heated. On the other hand, omega-6 polyunsaturated fats most definitely do! This is especially true in restaurants where the oil is heated for long periods of time – hours in fact. Those of you who have worked in the restaurant industry can likely attest to this practice.
In addition, the oil tends to be used several times before replacement with fresh oil. Someone I know who used to work for Chick-fil-A said the peanut oil in his restaurant was used all day long before replacing the following morning. While this may not be standard practice for all locations (hopefully not), you really don’t know what you’re getting when you pull into that drive-through.
Another issue from reused oil is from starchy food bits heated to high temperatures for long periods of time along with the oil. This introduces health risks from carcinogenic acrylamides in addition to the free radicals from the heated oil.
Moldy Peanuts?
Besides the issue of excessive omega-6 fats, potential mold issues in peanuts and their oil pose a danger to consumers.
Peanuts are particularly prone to mold with toxic species able to develop during storage in warm, humid months. These molds (Aspergillus flavus and Aspergillus parasiticus) produce a substance called aflatoxin that is a known carcinogen. This toxin can end up in oil made from affected peanuts. Thus, for those that are mold sensitive, peanut oil is probably not the best choice. (3)
Groundnut Oil Lectins
Despite peanut oil’s reputation as heart-healthy, it is considered atherogenic. This means that consumption promotes the development of fatty plaques in the arteries. How can this be? Peanut oil is low in cholesterol and contains phytosterols that compete with cholesterol for absorption in the digestive system, right? Watch out. This marketing spin is a total red herring!
Peanut oil is naturally high in lectins. These substances are common in legumes, grains, seeds, and nuts. They are powerful anti-nutrients and are irritating to the digestive tract in a manner similar to phytic acid. Soaking peanuts before roasting reduces levels of this anti-nutrient. (4)
The problem is that groundnut oil comes from unsoaked peanuts, meaning the lectins can still be present. Animal studies of peanut oil indicate that the lectins contribute to the hardening of the arteries, otherwise known as atherosclerosis.
Another study discovered that consuming a single handful of roasted peanuts caused intact lectins in the bloodstream within a few hours. Research animals with similar blood lectin levels as identified in that study develop heart disease.
Should You Use Peanut Oil or Eat at Restaurants that Use It?
In conclusion, avoiding peanut oil for home cooking is a wise idea. Far better choices are widely and affordably available that are much lower in inflammatory omega-6 fats without risk from aflatoxins and lectins.
With regard to eating at restaurants that use refined peanut oil, exercise caution. While an occasional meal cooked in refined peanut oil is not going to present an issue for most people, regular consumption of foods fried or cooked in it would not be advisable.
In our neck of the woods, we prefer Burger Monger to Five Guys, and our family never eats at Chick-fil-A (MSG headache waiting to happen). Burger Monger uses traditional beef fat for frying. Beef fat or tallow is a FAR healthier alternative for cooking and frying. When you use it, you don’t have to add MSG to the food to give it a synthetic beef flavor plus you have lower risk from rancid fat.
Did you know that McDonald’s used tallow decades ago for making french fries before it became politically incorrect in the 1980s to do so any longer? This is one big reason why fast food was healthier 30+ years ago than it is today!
Oh dear, I have been using unrefined sesame oil and walnut oil for baking. Sarah, am I loading my family with anti-nutrients?
Sesame oil is not the best choice for baking as it is quite high in polyunsaturated fats. Walnut oil is a huge no-no for baking … it should never be heated else you destroy its beneficial omega-3 fats. I would suggest trying avocado oil, expeller pressed coconut oil (has no taste), butter or ghee for baking.
If you think MSG causes headaches, then you might want to do a bit more research before writing articles advising people on nutrition…
There’s a lot of confusion about glutamate and MSG. Natural glutamate is of course fine, but even those who are sensitive can get headaches from it. MSG is the factory synthesized version of glutamate and it most definitely causes headaches in some people (I am one of them). I would urge you not to discount the experiences of others!
A light yellowish colour is not a definitive indication of refined peanut oil as I personally produce and filter mine at home with a light yellow colour.
Speaking on behalf of CFA, I must say that you know nothing about the actual way the chicken is cooked in a restaurant if you think it is reasonable or necessary to change the oil out several times a day. It is filtered and the fryer cleaned after (at most) every five batches. Furthermore, the chicken is cooked in huge fryers that hold gallons upon gallons of oil at a time. The cost of replacing all of that oil over and over throughout the day would be beyond prohibitive (Besides, new oil is added throughout the day as it is used). Any cook will tell you that using the same oil repeatedly, given that proper cleaning, filtering, and storing practices are followed, is neither unsanitary nor detrimental to quality. Let’s do some math, shall we? One tablespoon of refined peanut oil contains about 4 g polyunsaturated fats. 4 g of fat contains 36 calories. The Department of Health and Human Services dietary guidelines suggest you get 200 to 450 calories from unsaturated fats every day. I grant you that you have to add it up from all sources throughout the day, but that’s a pretty slim percentage. I’d hardly call it a “significant problem” or “worrisome.” Using a tablespoon of peanut oil to saute your chicken (which a lot of it you won’t even end up eating) isn’t going to contribute in any significant way to the nutrition of your meal, and I’d like to see someone fill up their deep fryer with ghee or avocado oil.
What type of oil do u think/would u recommend as the healthiest to use for baking?
Coconut oil, butter and ghee are all excellent. This is what I use.
is there a way to tell how refined your peanut oil is? all the label says is peanut oil.
Yes, if the peanut oil is a pale yellow color then it is almost certainly refined. See the picture at the beginning of the post and notice the color of the unrefined peanut oil. It is a reddish color.
The money grubbing non-profits like PETA & HSUS made it politically incorrect to cook with lard, butter, gee, and tallow back in the 1980s. These organizations are largely responsible for the rise of palm-nut oil. So now the poor orangutans don’t have a place to lay their heads because palm plantations have sprung up in the jungle displacing wildlife. Non-profit organizations and NGOs that peddle medical advise for “free” should be held to the same standard as medical doctors or multi-national drug companies, DO NO HARM.
Well, that tossed out the nutritional advise about eating whole grain cereals and nuts that the money grubbing non-profit organizations keep demanding that we switch to in order to save the whales… or are they worried more about pork chops going extinct?
Never cease to remember that decades ago these organizations were shrilly demanding that we switch from cooking with lard, tallow, and butter because it would quickly kill you and besides it was cruel to hogs, cafes, and cows. Well the Earth found a substitute for gee, butter, and lard, palm nut oil. Now organizations like PETA & HSUS are screaming about the poor orangutans, a species that the misnamed “HEALTH FOOD” industry are primarily responsible for putting into its current decline.
My husband eats lots of Kirkland brand cashews from Costco. The ingredients list cashews, peanut oil and salt. I’m thinking I should stop buying these and look for another snack.
What’s your opinion on these? I don’t know how they’re prepared or how much peanut oil he might be eating.
As an FYI, I’m eating an autoimmune diet and have added some nuts. I was experiencing some finger joint pain and decided to remove these cashews and the pain is gone.
Nuts unless they are soaked or sprouted first are soooo loaded with anti-nutrients. They can really cause issues for some people. I wouldn’t eat them otherwise. Here’s a source for soaked and sprouted nuts and nut butters: http://www.radiantlifecatalog.com/category/nuts-seeds-butters/?a=58537
Any reason why you don’t use olive oil at home?
I definitely have olive oil in my pantry. Isn’t that listed with the healthy fats that I use? Whoops. Thanks for bringing that up!