Heat and the Destruction of Gluten

"What temperature is required to destroy gluten?"

This question has been asked countless times over the years. Until now, we have not had any concrete answers.

All too often the gluten-free community runs into restaurants using the same deep frier for gluten items and their gluten-free items. Of course, we know this practice is not acceptable for those requiring truly gluten-free foods, but the uneducated think otherwise.

This study appearing at the International Celiac Symposium 2017 India, shows it's quite difficult to destroy gluten with temperatures used in customary cooking methods. And when it is destroyed, it's not safe to eat [not that gluten is safe to eat in its uncarbonized state...]

Resistance of gluten immunogenic peptides (GIP) to heat elimination in a homelike environment. Lessons for cross contamination prevention.

Rodriguez Herrera A2, Garcia Sanchez M2, Lamprea Moruno M2, Monje J3, Comino I1
1 Facultad de Farmacia, Spain, 2 IHP Group, Spain, 3 Universidad Pablo de Olavide, Spain

Verify effective elimination of Gluten Immunogenic Peptides (GIP) by home cooking techniques.

Batches of samples of gluten containing flour, potatoes, and potatoes plus flour matched to controls were tested. Each batch was cooked in laboratory by use of electric stove, gas stove, oil deep fryer, induction stove and water bath and was cooked at temperature range from 91-233°C (196-452 F) for 5 up to 30 minutes. GIP content was tested by GlutenTox® Sticks (KT- 5340 Biomedal Diagnostics) based on antibody G12.

On gas stove was necessary to keep 233 °C (451 °F) for 10 minutes to have absence of GIP detection. In range 190-200°C (374-392°F) incubation for 30 minutes was needed to have absence of GIP detection. Tests in temperatures below 190°C (374°F) showed presence of GIP at 10 and 20 minutes.

On induction stove temperature up to 246°C (475°F) for 6 minutes was needed to have negativity to GIP. Lower temperature ranges in spite of extended time up to 30 minutes were unable to get negative GIP. In oven processing never was got negative GIP signal, in spite of processing up to 210°C (410°F) and extended incubation time up to 45 minutes.

Samples processed on electric stove, water bath and deep frying showed presence of GIP in all ranges of time and temperature.

It is not realistic the elimination of gluten (GIP) at home kitchen by heat as temperatures higher that 200°C (392°F) are needed. Extended processing time is no compatible with conventional recipes. Fat processing over 200 is link with toxic metabolites generation which may be harmful. Use of oven or deep frying without proper cleaning may transfer GIP to meals when previously gluten containing meals were processed in these appliances.

Source: ICDS 2017 India Abstract Book PDF


On September 14th, 2020, Gluten-Free Watchdog presented their first-of-its-kind study to the Association of Official Analytical Collaboration (AOAC) International. This study measured the amounts of gluten found in gluten-free foods when cooked in fryers that previously fried gluten-containing foods.

Like the study above, Gluten-Free Watchdog shows that gluten cross contact in shared fryers is problematic for individuals with gluten-related disorders.

“Gluten-free foods cooked in shared fryers with wheat: A pilot study assessing gluten cross contact.”


Dietitians have long been discouraging consumers with celiac disease (CD) from ordering gluten-free foods cooked in shared fryers at restaurants.

This recommendation is based on presumed gluten exposure versus evidence-based research that gluten cross contact occurs. To the best of the authors’ knowledge there is no published data on gluten levels of gluten-free foods after cooking in shared fryers.

The lack of evidence of cross contact contributes to confusion among consumers, especially when gluten-free foods cooked in shared fryers (e.g., fries) are marked as gluten-free on some restaurant menus.

The purpose of the present study is to help inform consumer recommendations by assessing gluten levels of fries free of gluten-containing ingredients cooked in shared fryers with wheat.


The sandwich R5 ELISA found quantifiable levels of gluten in 9 of 20 (45%) orders of fries ranging from 7 to > 84 parts per million (ppm)(above the highest standard) (Table 1).

Five orders (25%) of fries tested above 20 ppm of gluten.

Fries from 6 of the 10 (60%) restaurants were found to contain quantifiable levels of gluten in at least 1 of the 2 orders, with fries from 4 of these 6 restaurants found to contain levels above 20 ppm of gluten in at least 1 of the 2 orders.

The competitive R5 ELISA found gluten in 3 of the 20 (15%) orders of fries ranging from 14 to > 283 ppm gluten (above the highest standard).


Results of this assessment suggest that gluten cross contact may occur when gluten free foods are cooked in shared fryers with wheat. While a much larger study may be warranted, it remains prudent to advise consumers with CD to avoid foods cooked in shared fryers.

It is impossible for a consumer to know how much gluten is in fryer oil and how much gluten may end up in an order of fries. Shared holding trays, scoops, and fryer baskets also are sources of potential cross contact.

The gluten levels reported in this investigation are likely underestimates due to the limitations of the analytical methods available for gluten analysis of foods heated to high temperatures

For more information (including PowerPoint presentation, video, and white paper):

9/27/20 - Added Gluten-Free Watchdog’s study.

Gluten-Free Cosmetics/Hair Care Products

When it comes to skin/hair/personal care products, gluten-free or gluten-full is a topic that has been debated for many years and continues yet today. It's an epic battle that rivals "Tastes Great - Less Filling". First, let us explore the science side of this.

Tastes Great! [Don't worry, it won't hurt you]

Several celiac experts (Dr. Peter Green - Celiac Disease Center at Columbia Univ., Dr. Stephano Guandalini - Univ. of Chicago Celiac Disease Center, Dr. Alessio Fasano - Univ. of Maryland Center for Celiac Research) say not to worry about gluten in hair/skin care products because the gluten must be consumed in order for it to cause a celiac reaction [villi damage]. Their reasoning, based on scientific evidence - size matters. The gluten proteins are simply too large to be absorbed by your body's largest organ - your skin.

Did you know - skin makes up about 16% of your body weight?

Cynthia Kupper, RD, Executive Director of the Gluten Intolerance Group of North America says:

"While investigating the possible absorption of gluten through the skin, I have talked with many regulatory organizations, and research and development people in the cosmetic industry. They all agree that gluten and all proteins are too large to be absorbed through the skin. Therefore, topical care products that contain gluten do not need to be avoided by persons with CD and DH."


According to Dr. Alessio Fasano, Medical Director of the Center for Celiac Research, University of Maryland,

“If you have celiac disease, then the application of gluten containing products to the skin should not be a problem, unless you have skin lesions that allow gluten to be absorbed systemically in great quantities.


Tricia Thompson, RD – The Gluten-Free Dietitian says:

"The bottom line: There is no scientific evidence that the use of gluten-containing products that are not ingested is harmful to persons with celiac disease. This includes individuals with dermatitis herpetiformis.


Doug Schoon, President of Schoon Scientific (scientific consulting for the cosmetics industry) -

"There is no scientific evidence to support claims that gluten can absorb through the skin. The burden of proof should be on those who make these statements. They should provide credible scientific evidence to back this unlikely claim.

What makes gluten unlikely to absorb? Substances with molecular weights (sizes) approaching 500 daltons are considered very poor skin penetrators because they are so large. Any bigger, they can’t possibly absorb into the skin, so they just sit on the surface. Gluten is huge — about 600 daltons — which is pretty monstrous; 15% larger than the theoretical maximum size.

Also, gluten is a protein and so is skin. Protein is attracted to proteins, so gluten is likely to bond tightly to skin making it more difficult to penetrate. So it has two things going against it. This is just another example of an unfounded cosmetic myth used to frighten people. The same holds true for lipstick. There is little scientific study that supports the notion that gluten in lipstick is a problem for people with Celiac disease."


Update 3/23/16 - add additional information about the size of gliadin and glutenin. Note: Molecular weight = Dalton

Most gliadin proteins have molecular weights (MW's) of 16,000 to 50,000.

Glutenin, however, consists of subunits of MW's 20,000 to 100,000 linked through intermolecular disulfide bonds into proteins with MW's of 50,000 to 2,000,000 or more.


Less Filling! [Hey that hurts!]

Even though science/medicine is telling us gluten cannot be absorbed through the skin - and thus not causing a reaction [ie villi damage], it's hard to ignore the countless number of celiacs/gluten sensitives that report they react to gluten in personal-care products. The reactions people experience are varied, many are topical (redness, itchy, burning, blisters] - due to gluten contact. Absorption is not needed for something like
Contact Dermatitis.

Could it be that the experts are using intestinal damage as their only gauge for a reaction? It seems they are saying
“If it doesn't cause intestinal damage, there's nothing to worry about.” Does that sound familiar? It should, because the gluten-free community went through this with Non Celiac Gluten Sensitivity (NCGS), where there is no intestinal damage. For years, experts told those with celiac-like symptoms and no villi damage that gluten was not the problem and NCGS didn't exist. Just because science fails to prove existence, doesn't mean that it fails to exist. Guess what - NCGS is now recognized. It does exist, who knew?

Could this be another instance where medicine hasn't caught up or it simply hasn't proven what patients have been experiencing? Not all medical professionals hold the status quo however...

Dr. Rodney Ford, Gastroenterologist & Allergist - Director of
The Children's Clinic & The Allergy Centre says

“Do not put food on your skin...Foods are for eating - not for skin care in people with food sensitivity. Although these creams promote that they are “natural”, it is best to put something inert on the skin (such as a fatty cream).”


People's reactions raise several questions:

Are they celiac reactions?
Are there other allergies at play?
Are the reactions
irritant dermatitis or allergic dermatitis?
Are they caused by gluten or some other ingredient in the product?
Science has studied only a handful of the proteins in wheat, could there be other proteins causing problems?

So many questions, so few answers.

You have the power

Regardless of the questions, the science, or the experts – you are in control – you can choose to listen to the science or “listen” to what your body is telling you - and make the appropriate choices. If you continue to have unexplained issues or you if you don't feel comfortable using products with gluten, seek out gluten-free personal care products. You just might be surprised at the results!



If you thought reading packaged food ingredient labels was difficult, it's child's play compared to the shampoo bottle. You'll need a degree in Molecular Chemistry and a secret decoder ring.

Cosmetics are not covered under the FDA's Food allergen Labeling and Consumer Protection Act of 2004 (FALCPA). This means wheat, barley, rye and oats do not have to be clearly or plainly listed – instead, they use complex chemical names. Here are some ingredient lists that should help decipher those labels.

Something to keep in mind, the ingredient “fragrance”could be from a gluten source. Even unscented products have fragrance that's used to mask the chemical scent. Also fragerances are considered “trade secrets” and their components do not have to disclosed on the label or on the phone.

I've also included rice, soy, corn, yeast, millet derived ingredients.

Wheat Derived Ingredients
Amp-Isostearoyl Hydrolyzed Wheat Protein Triticum Vulgare (wheat) Germ Oil
Cocodimonium Hydroxypropyl Hydrolyzed Wheat Protein Triticum Vulgare (wheat) Gluten
Disodium Wheatgermamido Peg-2 Sulfosuccinate Triticum Vulgare (wheat) Starch
Disodium Wheatgermamphodiacetate Wheat Amino Acids
Hydrolyzed Wheat Gluten & Wheat Flour Wheat Bran Extract
Hydrolyzed Wheat Protein/PVP Crosspolymer Wheat Germ Extract
Hydrolyzed Wheat Protein Pg-Propyl Silanetriol Wheat Germ Glycerides
Hydrolyzed Wheat Starch Wheat Germ Oil
Hydroxypropyltrimonium Hydrolyzed Wheat Protein Wheat Germamidopropalkonium Chloride
Laurdimonium Hydroxypropyl Hydrolyzed Wheat Protein Wheat Germamidopropyl Ethyldimonium Ethosulfate
Maltodextrin (verify starch source, may not be wheat) Wheat Protein
Sodium C8-16 Isoalkylsuccinyl Wheat Protein Sulfonate Wheat (triticum Vulgare) Bran Extract
Stearyldimoniumhydroxypropyl Hydrolyzed Wheat Protein Yeast Extract (verify source, it may not contain gluten)
Triticum Vulgare (wheat) Flour Lipids
Triticum Vulgare (wheat) Germ Extract

Barley Derived Ingredients
Amino Peptide Complex Hydrolyzed Malt Extract
Barley Extract Malt Extract
Hordeum Vulgare (barley) Extract Phytosphingosine Extract

Oat Derived Ingredients
Avena Sativa (Oat) Kernel Flour Hydrolyzed Oat Flour
Avena Sativa (oat) Kernel Protein Hydrolyzed Oat Protein
Avena Sativa (Oat) Kernal Extract Oat Beta Glucanoat Extract
Avena Sativa (Oat) Kernal Oil Oat Flour
Hydrolyzed Oats Sodium Lauroyl Oat Amino Acids

Soy Derived Ingredients
Glycine Soja (soybean)extract Peg-16 Soya Sterol
Glycine Soja (soybean)flour Peg-25 Soya Sterol
Glycine Soja (soybean) Oil Soy Phospholipids
Glycine Soja (soybean) Protein Soy Sterol
Hydrogenated Lecithin Soybean Extract
Hydrogenated Soy Glyceride Soybean Oil
Hydrolyzed Soy Protein Soybean Phospholipids
Lecithin Soybean Sterol
Mixed Soy Phospholipids Tocopherol
Peg-5 Soya Sterol Tocopheryl Acetate
Peg-10 Soya Sterol Tocopheryl Linoleate

Rice Derived Ingredients
Hydrolyzed Rice Extract Oryzanol
Oryza Sativa (rice) Bran Oil Rice Bran Oil
Oryza Sativa (rice) Starch Rice Starch

Yeast Derived Ingredients
Ceramide 2 Saccharomyces Extract
Ceramide 3 Saccharomyces Lysate Extract
Magnesium-Copper-Zinc Glycopeptides Saccharomyces Magnesium Ferment Extract
Saccaromyces/Magnesium Ferment Hydrolysate
Magnesium-Selenium-Copper-Zinc Glycopeptides Saccaromyces/Potassium Ferment Hydrolysate
Silicon-Zinc-Copper-Iron-Magnesium Yeast Glycopeptides Saccharomyces Zinc Ferment Extract
Saccharomyces Calcium Ferment Extract Yeast Extract Yeast Protein
Saccharomyces/Copper Ferment

Corn Derived Ingredients
Aluminum Starch Octenyl Succinate Corn Starch
Ascorbic Acid Corn Starch Modified
Ascorbyl Palmitate Corn (zea Mays) Oil
Caramel Hydrogenated Vegetable Oil
Corn Flour Sodium Ascorbate
Corn Oil Zea Mays (corn) Kernel Extract

Companies with Gluten-Free Products
Acure Organics Hugo Naturals
Afterglow Cosmetics - Gluten-Free by Gluten Free Certification Organization (GFCO) Intelligent Nutrients
Alterna John Masters
Arbonne Jonathan Product
BIOMEGA Costco's Kirkland
DermaOrganic Max Green Alchemy
Desert Essence Morrocco Method – Vegan/GF
Dove - Derivatives of gluten will be clearly labeled if present in the product. No Gluten Natural Girl Products
Ecco Bella Botanique
Finess Original Sprout
Garnier Renpure
Gluten-Free Savonerrie Sei Bella
Griffin Remedy Suave - Any wheat, barley, rye or oat ingredient will be clearly labeled.
HBL Surface – Salon quality
Head Organics Synergy

Maybelline Gluten Containing Ingredients
Avena Sativa (Oat) Bran Hydrolyzed Wheat Starch
Avena Sativa (Oat) Kernel Extract Hydroxypropyltrimonium Hydrolyzed Wheat Protein
Avena Sativa (Oat) Kernel Flour Laurdimonium Hydroxypropyl Hydrolyzed Wheat Protein
Avena Sativa (Oat) Kernel Oil Malt Extract
Cocodimonium Hydroxypropyl Hydrolyzed Wheat Protein Maltodextrin
Cyclodextrin Secale Cereale (Rye) Seed Flour
Dextrin Sodium C8-16 Isoalkylsuccinyl Wheat Protein Sulfonate
Dextrin Palmitate Sodium Lauroyl Oat Amino Acid
Disodium Wheat Germamphodiacetate Triticum Vulgare (Wheat) Germ Extract
Hordeum Vulgare Extract Triticum Vulgare (Wheat) Germ Oil
Hydrolyzed Malt Extract Triticum Vulgare (Wheat) Gluten
Hydrolyzed Oat Flour Triticum Vulgare (Wheat) Starch
Hydrolyzed Oat Protein Wheat Amino Acids
Hydrolyzed Oats Wheat Germ Glycerides
Hydrolyzed Wheat Flour Wheat Germamidopropalkonium Chloride
Hydrolyzed Wheat Gluten Wheat Protein
Hydrolyzed Wheat Protein Wheatgermamidopropyl Ethyldimonium Ethosulfate
Hydrolyzed Wheat Protein / PVP Crosspolymer Yeast Extract

Maybelline states they do not maintain a gluten-free list. Consumers need to read the ingredient lists of their products in order to determine the status.

Sources used in this post:


Gluten in Cosmetics: Results of Testing on Lipsticks and Lotions

´┐╝Inadvertent gluten ingestion from skin care products is a concern for those maintaining a gluten-zero lifestyle.

Two potential sources of ingestion are lotions and lipsticks. Tricia Thompson, MS, RD from Gluten-Free Watchdog and Thomas Grace decided to do gluten testing on two lotions and four lipsticks that contained gluten derived ingredients. This was a very small test, but I think the results will surprise you.

Sandwich and Competitive R5 ELISA test results on all six products returned less than 5 ppm and less than 10 ppm respectively. This means the products tested below detectable limits for each type of test.

To see the full results and get the authors' comments:



How many celiacs in Wisconsin?

I came across a Google Search looking for the number of celiacs in Wisconsin.

Now there could be a few variations of this question:

How many diagnosed celiacs?
How many potential celiacs?

Since I don't have time to research "How many diagnosed celiacs", I'm going to answer "How many potential celiacs?". Since we know the general prevalence of celiac, we can calculate an estimate.

First we start with population of Wisconsin

According to the
2010 US Census Bureau, Wisconsin has a population of 5,686,986.

Next we need the prevalence of celiac disease

2003 ground breaking medical study conducted by Dr. Fasano determined that ...

1 in 133 of normal, healthy people have Celiac Disease [most do not know it].
1 in 56 of those that have related symptoms.
1 in 39 of those that have a 2nd degree relative [aunt or cousin] with Celiac Disease.
1 in 22 in those that have a 1st degree relative [parent or sibling] with Celiac Disease.

Celiac Disease affects about
1% (3 million) of the population in the USA.

Time to fire up the calculator

If we apply the 1 in 133 - we get an estimate of 42,759 people
If we apply the 1% -
we get an estimate of 56,869 people that potentially could have CD

We can estimate the number of diagnosed. According to Dr. Peter Green
only about 10% of the 1% are actually diagnosed.

If we apply 10% to the 1% -
we get an estimate of 5,686 diagnosed celiacs in Wisconsin.

A bit more math reveals this:
approximately 51,183 people are currently undiagnosed.

Non-Celiac Gluten Sensitivity aka The Gluten Syndrome

Would you like to see an even larger number? It estimated that Non-Celiac Gluten Sensitivity affects anywhere from
6% to 40% of the population.

6% of 5,686,986 =
341,219 people that gluten affects adversely.
40% of 5,686,986 =
2,274,794 people that gluten affects adversely

That's a lot of people! Now, let's calculate the healthcare dollars chewed up because of gluten. Ooops, I don't have a calculator big enough for that task! "Hello NASA? Yeah, this is Al from GIG of ECW..."

If you'd like to calculate the numbers of your home town, check out our
Celiac Disease/Non Celiac Gluten Sensitivity Calculator.

Would you like to see these numbers broken down by county? Here ya go...
Wisconsin Counties
Estimated number of people with Celiac & NCGS
County 2010 Census

Est. # of Celiacs

Est. # of DX Celiacs

10% of 1%



Adams 20,875 209 21 1,253 2,088 8,350
Ashland 16,157 162 16 969 1,616 6,463
Barron 45,870 459 46 2,752 4,587 18,348
Bayfield 15,014 150 15 901 1,501 6,006
Brown 248,007 2,480 248 14,880 24,801 99,203
Buffalo 13,587 136 14 815 1,359 5,435
Burnett 15,457 155 15 927 1,546 6,183
Calumet 48,971 490 49 2,938 4,897 19,588
Chippewa 62,415 624 62 3,745 6,242 24,966
Clark 34,690 347 35 2,081 3,469 13,876
Columbia 56,833 568 57 3,410 5,683 22,733
Crawford 16,644 166 17 999 1,664 6,658
Dane 488,073 4,881 488 29,284 48,807 195,229
Dodge 88,759 888 89 5,326 8,876 35,504
Door 27,785 278 28 1,667 2,779 11,114
Douglas 44,159 442 44 2,650 4,416 17,664
Dunn 43,857 439 44 2,631 4,386 17,543
Eau Claire 98,736 987 99 5,924 9,874 39,494
Florence 4,423 44 4 265 442 1,769
Fond du Lac 101,633 1,016 102 6,098 10,163 40,653
County 2010 Census

Est. # of Celiacs

Est. # of DX Celiacs

10% of 1%



Forest 9,304 93 9 558 930 3,722
Grant 51,208 512 51 3,072 5,121 20,483
Green 36,842 368 37 2,211 3,684 14,737
Green Lake 19,051 191 19 1,143 1,905 7,620
Iowa 23,687 237 24 1,421 2,369 9,475
Iron 5,916 59 6 355 592 2,366
Jackson 20,449 204 20 1,227 2,045 8,180
Jefferson 83,686 837 84 5,021 8,369 33,474
Juneau 26,664 267 27 1,600 2,666 10,666
Kenosha 166,426 1,664 166 9,986 16,643 66,570
Kewaunee 20,574 206 21 1,234 2,057 8,230
La Crosse 114,638 1,146 115 6,878 11,464 45,855
Lafayette 16,836 168 17 1,010 1,684 6,734
Langlade 19,977 200 20 1,199 1,998 7,991
Lincoln 28,743 287 29 1,725 2,874 11,497
Manitowoc 81,442 814 81 4,887 8,144 32,577
Marathon 134,063 1,341 134 8,044 13,406 53,625
Marinette 41,749 417 42 2,505 4,175 16,700
Marquette 15,404 154 15 924 1,540 6,162
Menominee 4,232 42 4 254 423 1,693
County 2010 Census

Est. # of Celiacs

Est. # of DX Celiacs

10% of 1%



Milwaukee 947,735 9,477 948 56,864 94,774 379,094
Monroe 44,673 447 45 2,680 4,467 17,869
Oconto 37,660 377 38 2,260 3,766 15,064
Oneida 35,998 360 36 2,160 3,600 14,399
Outagamie 176,695 1,767 177 10,602 17,670 70,678
Ozaukee 86,395 864 86 5,184 8,640 34,558
Pepin 7,469 75 7 448 747 2,988
Pierce 41,019 410 41 2,461 4,102 16,408
Polk 44,205 442 44 2,652 4,421 17,682
Portage 70,019 700 70 4,201 7,002 28,008
Price 14,159 142 14 850 1,416 5,664
Racine 195,408 1,954 195 11,724 19,541 78,163
Richland 18,021 180 18 1,081 1,802 7,208
Rock 160,331 1,603 160 9,620 16,033 64,132
Rusk 14,755 148 15 885 1,476 5,902
St. Croix 84,345 843 84 5,061 8,435 33,738
Sauk 61,976 620 62 3,719 6,198 24,790
Sawyer 16,557 166 17 993 1,656 6,623
Shawano 41,949 419 42 2,517 4,195 16,780
Sheboygan 115,507 1,155 116 6,930 11,551 46,203
County 2010 Census

Est. # of Celiacs

Est. # of DX Celiacs

10% of 1%



Taylor 20,689 207 21 1,241 2,069 8,276
Trempealeau 28,816 288 29 1,729 2,882 11,526
Vernon 29,773 298 30 1,786 2,977 11,909
Vilas 21,430 214 21 1,286 2,143 8,572
Walworth 102,228 1,022 102 6,134 10,223 40,891
Washburn 15,911 159 16 955 1,591 6,364
Washington 131,887 1,319 132 7,913 13,189 52,755
Waukesha 389,891 3,899 390 23,393 38,989 155,956
Waupaca 52,410 524 52 3,145 5,241 20,964
Waushara 24,496 245 24 1,470 2,450 9,798
Winnebago 166,994 1,670 167 10,020 16,699 66,798
Wood 74,749 747 75 4,485 7,475 29,900
Totals 5,686,986 56,870 5,687 341,219 568,699 2,274,794