Gluten is a protein found in grains like wheat, barley, and rye. For people with celiac disease or non-celiac gluten sensitivity, consuming gluten triggers an immune response that damages the small intestine. This can lead to symptoms like abdominal pain, bloating, diarrhea, constipation, vomiting, fatigue, headache, anxiety, brain fog, and more. The only treatment is a strict lifelong gluten-free diet.
When it comes to cooking oils, most are naturally gluten-free. However, there are a few exceptions. Certain oils may be contaminated with gluten during processing if they are extracted from gluten-containing grains or manufactured on equipment shared with gluten-containing products.
So which oils are not gluten-free? Here is a quick overview of oils to avoid on a gluten-free diet:
– Wheat germ oil – Contains gluten since it is extracted from wheat germs
– Barley oil – Contains gluten since it comes from barley
– Rye oil – Contains gluten since it is made from rye
– Oils that use gluten-containing additives – Some oils have barley malt, wheat flour, etc. added
– Oils processed on shared equipment – Risk of gluten cross-contact
This article provides more details on these non gluten-free oils and how to identify them on food labels. Recommendations for safe, gluten-free oil alternatives are also provided.
What Makes an Oil Not Gluten-Free?
There are two main reasons an oil may contain traces of gluten and be unsafe for a gluten-free diet:
1. The oil is extracted directly from a gluten-containing grain.
2. The oil is processed on equipment shared with gluten-containing products.
Oils that fall into the first category include wheat germ oil, barley oil and rye oil. Since these oils come directly from gluten grains, they naturally contain gluten proteins.
The second risk applies to oils that are inherently gluten-free, but pick up traces of gluten during manufacturing. This cross-contact or cross-contamination can occur if an oil is produced on shared equipment or in the same facility as wheat, barley, rye or other gluten-containing ingredients.
Some oils also have gluten-containing additives like malt extract, wheat flour or barley malt added during production. This adds another source of gluten contamination.
So in summary, the main factors that make some cooking oils unsuitable for a gluten-free diet are:
– Extraction directly from gluten grains
– Shared equipment with gluten ingredients
– Use of gluten-containing additives
When evaluating oils for gluten, it’s important to consider the source, processing methods and any added ingredients.
Oils Extracted from Gluten Grains
Let’s take a closer look at some specific oils that are not gluten-free because they are extracted directly from sources of gluten – wheat, barley and rye.
Wheat Germ Oil
Wheat germ oil is pressed from the germ portion of the wheat kernel. The germ is the nutrient-dense core that goes on to become the new wheat plant if sprouted.
Since wheat is a prohibited grain for celiacs and those avoiding gluten, wheat germ oil is also off limits. During the extraction process, the gluten proteins naturally present in wheat get carried over into the oil.
In one lab analysis, wheat germ oil was found to contain over 2000 parts per million (ppm) of gluten. Anything over 20 ppm is considered unsafe for people with celiac disease.
Some people mistakenly think wheat germ oil must be safe since it comes from the germ, not the endosperm where most of the gluten is concentrated. However, lab testing shows the germ still contains very high levels of gluten proteins.
So wheat germ oil is definitively not gluten-free. It should be avoided by anyone following a gluten-free diet.
Barley Oil
Barley oil is extracted from whole barley grains. Barley is a close relative of wheat and contains gluten proteins. Therefore, barley oil is not considered gluten-free.
During the oil extraction process, barley gluten proteins are carried over into the final oil. One study found barley oil to have 1162 ppm of gluten, exceeding the safe limit.
Barley malt is also sometimes used to make barley oil. Barley malt contains gluten, adding another source of contamination.
Barley oil has a strong, distinctive taste and is sometimes used for flavoring rather than cooking. But it should be avoided on a strict gluten-free diet due to its high gluten content.
Rye Oil
Rye oil is pressed from rye grain seeds. Rye is a cereal grain closely related to wheat and barley. It contains prolamine proteins called secalins that are similar to the gliadin proteins in wheat. Secalins activate the immune response in people with gluten intolerance.
Since rye is a prohibited gluten grain, rye oil is also not permitted on a gluten-free diet. The extraction process transfers rye’s secalins into the oil.
Rye oil has a very strong, distinctive aroma. It is sometimes described as smelling like pumpernickel rye bread. Rye oil is often used for flavoring rather than as a cooking oil.
But due to the gluten content from its rye source, it should always be avoided by those adhering to a gluten-free lifestyle.
Oils with Added Sources of Gluten
In addition to oils derived from gluten grains, some oils have other sources of gluten added during production. This includes ingredients like malt extract, wheat flour or barley malt.
Malt Extract
Malt extract is produced from barley malt, an unrefined source of fermentable sugars. It is sometimes added to oils to impart a sweet, malted flavor.
However, barley malt contains gluten. So any oil using malt extract as an additive should be considered unsafe for gluten-free diets.
For example, some sesame oils incorporate barley malt extract for enhanced flavor. One study found sesame oil with malt extract to contain over 200 ppm of gluten.
Always check the ingredients list for malt extract before purchasing flavored oils. Oils flavored with malt extract should be avoided on a gluten-free diet.
Wheat Flour
Wheat flour is another ingredient occasionally added to oils, especially infused olive oils. The flour adds viscosity and flavor.
However, wheat flour contains the gluten protein gliadin. Using wheat flour as an ingredient makes the oil unsuitable for gluten-free diets.
One study detected over 2000 ppm of gluten in an olive oil infused with wheat flour. So be sure to avoid any oils using wheat flour as an additive.
Barley Malt
Like malt extract, barley malt is sometimes added to oils for flavor enhancement. Barley malt imparts a malted, beer-like taste.
However, barley malt contains gluten. Oils flavored with barley malt can test over 100 ppm for gluten.
For example, one study found canola oil with barley malt had 153 ppm of gluten. This exceeds the safe threshold for gluten-free.
Carefully read ingredient lists and avoid purchasing oils containing barley malt. Opt for malt-free varieties certified gluten-free if you follow a gluten-free diet.
Oils Processed on Shared Equipment
In addition to the ingredient source itself, cross-contact during manufacturing can also introduce gluten into oils:
– Shared equipment – Being produced on the same equipment as gluten-containing products
– Shared facilities – Being made in the same facilities as gluten-containing products
– Shared storage/transport – Being stored or transported with gluten-containing products
Since oil processing equipment is difficult to completely clean between production runs, traces of gluten can remain and contaminate subsequent batches. Gluten cross-contact can also occur if multiple products are handled in the same facility.
This risk applies even to oils that seem intrinsically gluten-free, like canola oil, sunflower oil or safflower oil.
One study looking at restaurant fryer oils found sunflower, canola and vegetable oil to all contain measureable levels of gluten, indicating cross-contact.
So when choosing oils, it’s safest to look for those specifically produced in dedicated gluten-free facilities and transported/stored separately from gluten-containing foods.
Identifying Non Gluten-Free Oils on Labels
Reading the label is important to identify oils that are not gluten-free. Here are some things to look for:
Contains Wheat, Barley or Rye
Ingredient lists that mention wheat, barley or rye indicate the oil has been extracted from a gluten grain. Oils listing these ingredients, like wheat germ oil or barley oil, should be avoided.
Malt Extract, Wheat Flour, Barley Malt
Scan the ingredients list for additives like malt extract, wheat flour or barley malt. Oils containing these added sources of gluten should not be consumed on a gluten-free diet.
Made on Shared Equipment/Facility
Some labels state if shared equipment or facilities were used during manufacturing. This increases the risk of gluten cross-contact. Choose oils made in dedicated gluten-free facilities when possible.
Not Labeled Gluten-Free
Oils labeled “gluten-free” have been tested to verify they meet regulatory standards for gluten content (under 20 ppm). Oils without a “gluten-free” label may still contain trace amounts of gluten.
No Third Party Certification
Look for oils certified gluten-free by reputable third-party organizations like GFCO, the Gluten Intolerance Group or the Celiac Support Association. This provides added assurance the oil was properly tested.
Gluten-Free Oil Alternatives
Fortunately, there are still plenty of oil options that are naturally gluten-free and safe for a gluten-free diet:
Refined Oils
Highly refined oils like canola, vegetable, corn, peanut, soybean, safflower and sunflower are reliably free from gluten. Opt for major brands that processes oils in dedicated facilities.
Cold-Pressed Oils
Unrefined, cold-pressed oils like olive, coconut, avocado and walnut oil are naturally gluten-free. Choose oils that are third-party certified or made in gluten-free facilities.
Flavored Oils
Flavored oils like chili, lemon, basil and garlic infused olive oils are safe as long as they don’t contain gluten additives. Once again, look for gluten-free labels or certifications.
Sesame Oil
Plain sesame oil that is pure-pressed and doesn’t contain malt extract or other gluten sources is gluten-free. Tamari wheat-free soy sauce can sub for malt extract.
Rice Bran Oil
Rice bran oil extracted from rice is gluten-free. Make sure no barley has been added. Look for gluten-free certification.
Sticking to highly refined, flavored and cold-pressed oils made in dedicated facilities with proper protocols helps minimize the risk of gluten exposure on a gluten-free diet.
Frequently Asked Questions
Is canola oil gluten-free?
Yes, pure canola oil is considered gluten-free. Canola oil is extracted from rapeseed and thoroughly refined. It contains very little protein. Look for reputable brands produced in dedicated gluten-free facilities to reduce cross-contact risks.
Is vegetable oil gluten-free?
Most pure vegetable oils like soybean, corn and safflower oil are naturally gluten-free. However, Always check labels to confirm the vegetable oil was processed in a gluten-free facility on dedicated equipment and packaged separately from gluten products.
Is olive oil gluten-free?
Yes, pure olive oil is gluten-free. Make sure any added flavors like garlic or chili are also free from gluten-containing ingredients. Check for certifications from GFCO, GIG or CSA for extra assurance.
Is coconut oil gluten-free?
Yes, coconut oil made from pressed coconut meat is gluten-free. Avoid any additives made from gluten grains. Look for reputable brands of coconut oil produced in gluten-free facilities.
Is avocado oil gluten-free?
Yes, pure avocado oil extracted from avocado pulp is gluten-free. Be aware that some mass-produced avocado oils use potential gluten cross-contaminants during processing, so certified gluten-free oils are safest.
Is sunflower oil gluten-free?
Pure sunflower oil is naturally gluten-free, but gluten cross-contamination is possible during processing. Look for trusted brands of sunflower oil that are third-party certified gluten-free for extra assurance.
Is peanut oil gluten-free?
Yes, refined peanut oil is considered gluten-free. Peanuts are naturally gluten-free. Opt for major brands of peanut oil made in dedicated gluten-free facilities to reduce the risk of cross-contact with gluten-containing products.
The Bottom Line
Most cooking oils are naturally gluten-free, but some specialty oils derived from gluten grains or exposed to gluten during processing may contain traces and are not considered safe for gluten-free diets.
To identify oils to avoid, watch out for:
– Wheat germ oil
– Barley oil
– Rye oil
– Oils with malt extract, wheat flour or barley malt
– Oils made on shared equipment with gluten products
Instead choose:
– Refined oils like canola, soybean and peanut oil
– Cold-pressed oils like olive, coconut and avocado oil
– Flavored oils without gluten-based ingredients
– Oils that are certified gluten-free by reputable third parties
By understanding where gluten contamination can occur and reading labels carefully, you can enjoy delicious gluten-free oils as part of your diet. With so many safe options available, avoiding problematic oils is much easier.
