Vegetable oils (actually seed oils) are one of the unhealthiest oils you can consume. They are rich in trans fat, which is a synthetic fatty acid that inhibits your body’s production of prostacyclin, a factor that keeps your blood flowing smoothly. If your body cannot produce enough prostacyclin, blood clots can form in your arteries, increasing your risk of heart disease. Aside from endangering your cardiovascular health, trans fat may even impair your memory. According to a study published in Time, participants who consumed high levels of trans fat remembered 11 fewer words compared to those who consumed lower levels.
Much of the reason why vegetable oils contain trans fat is because they are hydrogenated, a process wherein hydrogen gas is forced into the oil at a high pressure during manufacturing. Companies use this method to extend the shelf life of their products, but at the cost of people’s health.
Furthermore, vegetable oils produce oxidized cholesterol when heated, increasing thromboxane formation, a factor that clots your blood, as well as two toxins: cyclic aldehydes and acrylamide. (Mercola.com)
In light of all this information, which vegetable oils should you avoid? Here are some common vegetable oils and why you should avoid them:
Canola Oil
You may have seen plenty of advertisements that present canola oil as a safe and healthy cooking ingredient. Unfortunately, this is not true, as canola oil can introduce oxidized cholesterol into your body when consumed. See more HERE
Corn Oil
Corn or maize oil is extracted from the germ of corn. It’s mainly used for cooking and is also a key ingredient in margarine and other processed foods.5 Corn oil is also used in various industrial applications, such as stock for biodiesel6 and a constituent in the production of resins, plastics and lubricants, to name a few.7
Despite being generally less expensive than other vegetable oils on the store shelf,8 a huge factor in its price is the staggering amount of subsidies the United States gives to corn to underwrite the cost. Corn is one of the most heavily subsidized crops in the country, raking in over $111.2 billion from the government between 1995 and 2017, according to data from the Environmental Working Group (EWG).9
As you can see, this subsidy on a basically unhealthy food easily undersells healthy choices. A study published in the Journal of the American Medical Association shows that the high consumption of foods derived from subsidized commodities like corn is associated with an increased risk of cardiometabolic disease in adults.10
Moreover, the problem with using corn oil and other vegetable oils for cooking is that they contain perishable bonds that create free radicals in the presence of oxygen, a process also known as autoxidation.11 These free radicals can lead to cholesterol oxidation, which has been linked to an increased risk of diseases such as atherosclerosis, Alzheimer’s disease, retinal degeneration, age-related macular degeneration and cataracts.12
Corn oil also contains very high amounts of omega-6 fats, which can throw your body’s omega-6 to omega-3 ratio out of balance. Corn oil is reported to have an omega-6 to omega-3 ratio of 46-to-113 — a far cry from the ideal 1-to-1 ratio. The standard American diet already has far too much omega-6 in it, and the serious distortion of the ratio further increases your risk for many degenerative diseases.14
Uses of corn oil
Apart from serving as a less-than-ideal cooking oil, corn oil is used in manufacturing paint, ink, textiles and insecticides.15 It also sometimes functions as a carrier oil for drug molecules in pharmaceutical products.16
Corn oil is used for skin care products as well, including soaps, balms and other bathing essentials.17 You can also massage it onto your scalp to help strengthen and add shine to your dry hair.18 Here are some of the ways you can use corn oil around your home:
- Lubricate a key lock — If you have a sticky key lock at home, wipe the key with corn oil before inserting it into the lock. The oil acts as a lubricant, making it easier for you to turn and pull out the key.19
- Clean up watermarks from wooden furniture — Mix equal parts of salt and corn oil then rub it onto the watermarks on your wood furniture. Use a clean cloth to polish it off.20
- Coat your snow shovel — Rubbing the oil on your shovel will prevent snow from sticking to it.21
Composition of corn oil
According to the United States Department of Agriculture, industrial and retail corn oil contains 27.5 grams of total monounsaturated fats, 54.6 grams of total polyunsaturated fats and 12.9 grams of total saturated fats per 100-gram serving.22
One important caveat you need to consider regarding this oil is that it’s typically derived from genetically modified (GM) seeds that are designed to resist herbicides like glyphosate.
A study published in the International Journal of Biological Sciences demonstrates the toxicity of three GM corn varieties from biotech company Monsanto, now Bayer. Results show that consuming GM corn increases the risk for hepatorenal toxicity and unintended direct or indirect metabolic consequences.23
How corn oil is made
To extract corn oil from the corn germ, a combination of continuous screw presses and solvent extraction is used. The initial expeller extracts around 50% of the oil content, while the solvent extraction brings the total yield to 95%. The corn oil is then refined through degumming to remove phosphatides, alkali treatment to neutralize free fatty acids and bleaching to remove trace elements and create a desirable color.
The final steps of the refining process include winterization, a process wherein high melting waxes are removed, and deodorization.24 This entire process may contribute to the potential health risks of corn oil.25
Is corn oil safe?
Corn oil and other polyunsaturated vegetable oils are heavily marketed for “healthful” cooking alongside the vilification of saturated fats, which actually do not cause heart disease and, on the contrary, serve as a healthful addition in your diet.28 Aside from the oxidized oil dangers I discussed in the first section, here are two other issues you should be aware of with corn oil and vegetables oils:
- The majority of these vegetables oils in the U.S. are made from genetically modified crops,29 which can contain residues of the herbicide glyphosate and Bt toxin found in GM corn and soy.
- They are heavily processed, potentially causing a range of ill health consequences.30
Side effects of corn oil
Some of the worst foods you can consume are those cooked with polyunsaturated vegetable oils like corn oil.31 The introduction of oxidized cholesterol into your system is a big concern, converting your good cholesterol into bad, which leads directly to cardiovascular diseases.32
When heated, corn oil produces harmful chemicals called aldehydes, which have been found to increase the risk for autism spectrum disorder, Parkinson’s disease and gastric, breast and prostate cancer.33 A study published in the Journal of Lipid Research also shows that polyunsaturated fatty acids promote hepatic inflammation.34
If you’re looking for a cooking oil that is less susceptible to heat-induced damage and will not put you at risk of various chronic diseases, consider using coconut oil. Coconut oil contains healthy fats that may help support your heart health,35 thyroid function,36 immune system,37 brain function38 and metabolism,39 among others.
Cottonseed Oil
A fairly common vegetable oil in the U.S. and was used as early as the 1800s.6 It was called “America’s original vegetable oil” and created a high demand among its consumers.7 Cottonseed oil is similar to canola, corn, safflower, soybean and sunflower in terms of its polyunsaturated fat oil composition.8 In its nonhydrogenated form, it can be used for deep frying to lower the amounts of trans fat in fried foods.9 Cottonseed oil may have health-damaging side effects due to the ingredient it’s made from and the manufacturing process used to extract it. Not long after cottonseed oil infiltrated our food supply, diseases such as heart disease, diabetes, cancer, multiple sclerosis, and autism skyrocketed.a
Among the many crops grown in the United States is cotton. According to the National Cotton Council, roughly 162 pounds of cottonseed are produced for every 100 pounds of fiber.1
The raw cottonseed actually consists of three commodities: linters, which are cotton fibers still clinging to the harvested seeds and which are used to make a variety of products, from paper money to cosmetics to photography film; the hulls, which are pressed into a meal or used as a bulk food in the livestock feed industry; and the kernels inside the hulls, which are crushed to produce the oil.2
As an agriculture product in the U.S., cottonseed oil is considered to be “one of the country’s most important sources for vegetable oil,” according to the Agricultural Marketing Resource Center.3 While cottonseed oil is also touted by the industry to be “cholesterol-free with a high level of antioxidants,” making it a “premium oil” for cooking, baking and use by the processed (snack) food industry,4 fine food magazines such as Bon Appetit warn that it’s one of the top three “least healthy” oils for you.5
Uses of cottonseed oil
Cottonseed oil is known for its culinary purposes. It’s used for frying or baking, and added to salad dressings,10 baked goods, cereals and mayonnaise.11 Because of its neutral taste, cottonseed oil will not mask or overpower the other flavors in your dish, unlike other oils.12 It’s a familiar feature of processed foods,13 like potato chips14 and French fries,15 which I absolutely recommend you avoid if you want to achieve optimal health.
Cottonseed oil is added to margarines, icings and whipped toppings because of its potential to help form beta prime crystal, which gives these food products a smooth and creamy appearance and consistency.16
Cottonseed oil is also added to personal care products such as soap and cosmetics,17 lubricants, nail polish removers, fertilizers18 and laundry detergents.19 This oil is even added to soaps used in washing wool. In the first half of the 20th century, cottonseed oil was also used as an excipient in drugs like penicillin and vaccines, but was replaced by peanut oil after cotton seed allergy reactions began being reported.20
Today cottonseed oil is one of many used as emulsifiers and excipients approved for use in a range of drugs and vaccines.21,22
Composition of cottonseed oil
Cottonseed oil is mainly composed of polyunsaturated fatty acids (PUFAs), with linoleic acid making up a majority of its PUFA content.23 Other fatty acids that can be found in cottonseed oil include palmitic acid, myristic acid, palmitoleic acid, stearic acid, oleic acid and linolenic acid. The fatty acid composition of nonhydrogenated cottonseed oil is:24
- Saturated fat — 27%
- Monounsaturated fat — 18%
- Polyunsaturated fat — 55%
When partially hydrogenated, cottonseed oil’s fatty acid profile is altered and its monounsaturated fatty acid (MUFA) concentrations increase:
- Saturated fat — 29%
- Monounsaturated fat — 50%
- Polyunsaturated fat — 21%
How is cottonseed oil made?
Although cotton farming goes back centuries — with the cultivation of it being evident even in prehistoric times — cottonseed oil production is relegated to more recent history, when it became part of a milling process.25 This is different from mills seen today, which are either screw press or solvent extraction facilities.26 Modern processing of cottonseed oil involves numerous steps, and the main techniques include:27
- Alkali refining
- Bleaching
- Winterization
- Hydrogenation
- Deodorization
- Interesterification
Because it’s naturally stable, cottonseed oil requires less hydrogenation compared to other oils, and this results in lower trans fat levels.28
Does cottonseed oil have any health benefits?
Some of the health benefits you may have heard about cottonseed oil is that it’s “healthy” because of its high unsaturated fat levels that exhibit total cholesterol-, low-density lipoprotein (LDL)- and triglyceride-lowering properties.29 It’s also touted for producing low levels of trans fats when used for deep-frying foods30 and for its low amounts of saturated fat.31
From a nutrition standpoint, cottonseed oil, along with almond oil and wheat germ oil,32 also has high concentrations of vitamin E,33 a nutrient that may play a role in lowering your risk for diseases, such as Alzheimer’s disease, cardiovascular disease and prostate cancer.
Conventional health experts advise getting vitamin E from vegetable oils like cottonseed oil, because people do not eat foods rich in this nutrient on a daily basis.34,35 It is also believed that vitamin E contributes to the long shelf life of cottonseed oil.36
However, I disagree with these health claims. As much as possible, don’t use vegetable oils like cottonseed oil, whether it’s hydrogenated or not, and whether it’s unrefined or processed. It can negatively impact your health in multiple ways, as explained in the remaining sections. There is only one truly stable and healthful oil to use, and that is high-quality organic coconut oil.
The drawbacks of unrefined and refined cottonseed oil
Initially, cottonseed contains gossypol that’s responsible for the oil’s yellowish color.37 This substance can be toxic to nonruminant animals (only adult cattle and sheep are known to metabolize it38) and reacts with protein and lessens the oil’s nutritional value.39
Increased amounts of gossypol have been linked to adverse effects like breathing problems, anorexia and heart, lung, liver and blood cell problems.40 This compound also triggered reproductive health problems among female nonruminant animals, particularly by disturbing “estrous cycles, pregnancy and early embryo development,” and among male animals by causing infertility, sperm immotility and reduced sperm counts.41
In attempts to make this oil less damaging to your health, manufacturers came up with the following areas of improvement for cottonseed oil production:42
- Lowering or eliminating gossypol in cottonseed oil
- Increasing the yield of cottonseed oil extraction
- Increasing the oil’s PUFAs and vitamin E concentrations
- Reducing saturated fatty acids
Another step the industry took as far back as 2007 was to implement “educational” marketing campaigns stressing the nutritious aspects of the nonhydrogenated oil, including the fact that “it does not require hydrogenation, the process that produces trans fatty acids,” thus making it “trans fat free.”43,44
And while the U.S. Food and Drug Administration (FDA) banned trans fats and partially hydrogenated oils in May 2018,45,46 the makers of Crisco shortening, a hydrogenated product, was already prepared, having introduced a new trans fat-free version of its product, made from sunflower, soy and cottonseed oils, in 2008.47
Even though being trans fat-free is a good thing, USDA data from July 2018 still show that 94% of the cotton crop grown in American soil is actually genetically engineered, which could leave questions as to how safe or nutritious cottonseed oil really is.48
Although GE proponents dismiss the concerns,49,50 GE crops have been linked in the past to possible reproductive problems, organ disruption,51 digestive problems52 and questions about possible allergic reactions.53 Some published reports have also highlighted that cottonseed oil contains a high pesticide load54 and is susceptible to mold contamination.55,56
Source: Mercola.com
in Dr. Weil’s book, Eight Weeks to Optimum Health, one of the first things he asks readers to do is to go through their pantry shelves and throw out anything made with cottonseed oil. The list includes such things as chips, cookies, crackers, bread, salad dressings — even soaps, shampoos, and makeup.
He regards it as unhealthy because it is too high in saturated fat and too low in monounsaturated fat. He also says that cottonseed oil may contain natural toxins and probably has unacceptably high levels of pesticide residues (cotton is not classified as a food crop, and farmers use many agrichemicals when growing it). He warns to be on the lookout for cottonseed oil in packaged foods and avoid products that contain it. Manufacturers like it because it’s cheap, and products that say “may contain one or more of these oils” and list cottonseed, will almost certainly contain it.
Peanut Oil
Of the many kinds of oils1 peanut is a mildly sweet edible oil. Also called groundnut or arachis oil,2 it’s made from Arachis hypogea, a low-growing, annual plant that is a member of the Fabaceae (Leguminosae) family. Despite the word “nut” in its name, peanut is actually a legume and grows underground,3 as opposed to other nuts like walnuts and pecans, which grow on trees (hence are called tree nuts).
Peanuts originated in South America,4 and they have a long place in history. According to the National Peanut Board, peanuts were used as sacrificial offerings by the Incans of Peru, who placed them alongside their mummies to help them cross over into the next life.
Ancient tribes in Central Brazil made a beverage from ground peanuts and maize. This is also where Europeans first came across this plant, and then brought it back to Spain. From there, the humble peanut spread to Asia and Africa, and then eventually to North America.5 As of 2018 the top four producers of peanuts worldwide are China, India, Nigeria and the United States.6
Types of peanut oil
Peanut kernels are eaten boiled or roasted, or crushed or chopped for use in cooking and confectionery. They also can be transformed into other products like peanut butter, peanut flour and peanut oil. According to The Peanut Institute, there are several types of peanut oil sold today:7
•Refined peanut oil — This is a processed product that’s largely used in the fast food industry. The refining procedure includes bleaching and deodorizing. Since the process also removes the peanut proteins, this oil is nonallergenic and safe for people with peanut allergies.
According to The Peanut Institute, the refining process also produces an oil that prevents it from absorbing the flavors of the foods cooked in it, making it a favorite for restaurants that need to cook multiple items in the same batch of oil without the foods picking up each other’s flavors.
•Gourmet roasted peanut oil — This oil is not refined and is valued because it retains many of the peanut’s nutrients such as pytoesterols and vitamin E. Because it maintains its aromatic flavor, The Spruce Eats8 mentions that this type of peanut oil is often used for flavoring, rather than cooking, sometimes added into dressings, sauces and marinades or drizzled over a salad.
The Spruce Eats also mentions two other peanut oil products that some chefs might choose for certain recipes:
- Virgin or cold-pressed peanut oil — Since it’s not refined, most of its natural flavors and aromas are still present. It has a light flavor that will not overpower the flavors of other ingredients.
- Peanut oil blends — These are varieties that have been blended with cheaper oils like soybean oil. As a result, you can buy them at a lower price. The oil it’s blended with usually has a high smoking point as well.
For the best nutrients and unadulterated product, always look for packaging that says “100% peanut oil” on it. That way you don’t have to worry about whether you’re getting soybeans in your oil, which may be tainted with pesticide or herbicide residues.
Uses of peanut oil
Peanut oil is currently one of the most popular oils used in the kitchen, as it can be used for frying, sautéing or simply adding a mild nutty flavor to dishes. Asian cultures, particularly China, Laos, Vietnam and Cambodia, are fond of using peanut oil in their food preparation.9
Before you liberally use this oil for cooking, though, please remember that it has a high percentage of omega-6 fats, which can upset your omega 3 to 6 ratio, which can increase your risk of obesity, diabetes and heart disease.10 I advise you to limit your use of peanut oil for cooking or frying, and preferably use it without heating.
Peanut oil can also be used for aromatherapy; Stylecraze gives a few other ideas on how to use it:11
- Moisturize your skin by applying the oil to your face and washing it off after 20 minutes.
- Apply to your hair to help boost growth, moisturize split ends and regenerate damaged hair.
- Rub it on your scalp to help address dandruff and ease psoriasis.
Composition of peanut oil
The stability and shelf life of peanut oil are mainly brought on by its fatty acid composition.12 It is composed of 10.7% saturated fats, 71% monounsaturated fats and 20.9% polyunsaturated fats. The main fatty acids are oleic, palmitic and linoleic acids.13
Peanut oil has an extensive shelf life, provided it is stored properly. Unopened peanut oil can stay fresh for up to two years, but if opened, it only stays fresh for six months to one year. Store it in a cool, dry place, such as your pantry, away from sunlight. Make sure the bottle is closed tightly.14
Benefits of peanut oil
Peanut oil may have benefits against diabetes, as suggested by a 2006 animal study. The researchers studied the effect of groundnut oil on lipid profile, blood glucose, lipid peroxidation and antioxidant status among diabetic rats. They found that it “slightly but significantly decreases the blood glucose, HbA1c, lipid peroxidation and lipid profile, and increases antioxidant levels in diabetic rats.”15
Another study found that peanut oil, as well as other peanut products like peanut butter, contain phytosterols (PS), which help reduce the risk of cancer.16
Despite its wealth of uses and potential benefits, peanut oil is not safe for everybody, mainly because of its allergens, which account for the majority of severe food-related allergic reactions.17 They’re also contaminated with a potentially dangerous toxin — more on this below.
Is peanut oil safe?
Having a peanut allergy is no laughing matter, as it’s one of the most severe food allergies known, and can lead to fatal side effects. If you have (or suspect you have) a peanut allergy, I advise you to avoid consuming peanut oil, even in very small amounts — don’t even apply it topically.
Also, keep in mind that peanut oil is added to certain foods, so always read the label when grocery shopping. If you’re dining out, ask your server to check if your food contains or is cooked with peanut, arachis or groundnut oil.
I also advise pregnant women and nursing moms to use peanut oil with caution. Consult your health care provider to find out if it’s safe for you and your infant. If you have sensitive skin, do a skin patch test before using this oil topically.
Another reason why you should be cautious of peanut oil is that this plant is often heavily sprayed with pesticides and contaminated with a mycotoxin called aflatoxin.18 This is a toxic metabolite that comes from certain molds and fungi like Aspergillus flavus and Aspergillus parasiticus.19 They thrive in soil and in moist environments.
Peanuts can become contaminated during preharvest, storage or processing. Aflatoxin may cause side effects such as leaky gut and may even increase your risk of liver cancer.20
Anaphylaxis is a dangerous and sometimes deadly side effect of peanuts and peanut oil. If you have a peanut allergy and have unknowingly ingested or used peanut oil, you may experience severe side effects, such as difficulty breathing, swollen lips and throat, fainting, dizziness and chest congestion. Seek emergency health care immediately, as this can be fatal.21
Safflower Oil
Safflower oil is one of the many edible oils in the market lauded for positive health effects. While there may be some truth to this, there are many potential disadvantages to consider when using this oil. Learn more about my recommendations on safflower oil and discover if its benefits outweigh its risks.
Safflower oil is derived from the seeds of the safflower plant (Carthamus tinctorius L.), an annual broadleaf crop from the Compositae or Asteraceae family:1 Native to many parts of Asia, the Middle East and Africa, the safflower plant is referred to as “kusum” in India (derived from the Sanskrit word “kusumbha”) and as “hongua” in China.
One of the world’s oldest crops, safflower has a history that goes back 4,000 years to ancient Egypt. While the initial evolution of growing safflower oil commercially began in the U.S. Great Plains in 1925, its large-scale production was not in full swing until the 1950s.
India is currently the largest leading commercial producer of safflower oil worldwide, followed closely by California in the United States and Mexico. Western states such as North Dakota and South Dakota, Montana, Idaho, Colorado, Arizona and Nebraska also produce substantial amounts of safflower, but on a rather small acreage.
Soybean Oil
A popular form of vegetable oils, soybean oil is extracted from soybean seeds.1 There has been much hype about its touted health benefits, but there’s more to soybean oil than what’s advertised on product labels. It could be very problematic to use in cooking, due to manufacturing processes and the presence of genetically engineered varieties. Get the lowdown on this food staple, and why it is one of the worst oils for cooking.
Soybean oil is extracted from soybean (Glycine max) and often has a dark yellow or faint green color. Standard vegetable oil is typically composed of soybean, corn, safflower and palm oils.2
The first domestic use of soybeans is traced to the eastern half of North China in the 11th century B.C., although as early as 2853 B.C., the plant was considered a sacred plant of China along with rice, wheat, barley and millet. By 1895, Chinese soybean production expanded overseas when the Japanese began importing soybean meal to serve as fertilizer.3
Soybean shipments to Europe began around 1908, although Europeans had been aware of soybeans as early as 1712. The story of soybeans in the United States began in the early 1800s, with North Carolina having one of the first soybean plantations.4
As of 2016, Americans were consuming more than 28 billion pounds of edible oils annually, with soybean oil comprising about 80 percent of that number. Worsening the problem further at the time was that soybean oil was highly processed and hydrogenated.5
Among the problems with partially hydrogenated soybean oil is trans fat and the health hazards of the soy itself, as well as the prevalence of genetically engineered soybeans. According to the U.S. Department of Agriculture (USDA), 94 percent of soybeans today are grown using herbicide-tolerant seeds.6
Thankfully, in an effort to address health concerns that partially hydrogenated oils (PHOs) — the primary dietary source of trans fats — could be causing thousands of heart attacks and deaths each year, the FDA decided in 2015 that PHOs no longer should be considered “generally recognized as safe (GRAS), and started a campaign wherein food manufacturers were given three years to phase out trans fat from their products, with the ban officially taking effect on June 18, 2018.
This marked a turning point for public health, as The Washington Post reported that trans fat consumption soon drastically lowered. Between 2015 and 2018, companies were able to remove 98 percent of trans fat from the market.7 Later, in a gesture to allow what they called “an orderly transition in the marketplace,” the U.S. Food and Drug Administration extended the date for these foods to get completely off grocery store shelves to January 1, 2020.8
