No, Gluten-Free Diets Do NOT Cause Diabetes: New “Study” Has Serious Flaws
By Lisa Egan
Take a look at some headlines that have been flooding the internet [recently]:
Gluten-Free Diets May Be Tied to an Increased Risk of Type 2 Diabetes
Going Gluten Free May Raise Your Risk of Type 2 Diabetes
Downside to Gluten-Free Diets: Diabetes Risk?
Type 2 Diabetes Linked to Low Gluten Diets
Gluten-Free Diets Could Lead to Deficiencies and Cause Illness
Low-Gluten Diet May Be Linked to Diabetes Risk
Gluten May Be Healthier For You Than You Think
Going Gluten-Free Might Actually Increase Your Risk of Diabetes
What were your first thoughts upon reading those headlines?
Did they make you think that avoiding gluten will increase your risk of developing one of the most dangerous chronic conditions that plagues humanity…and that maybe consuming gluten is actually GOOD for you?
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Here’s the source of disinformation those articles used as a reference:
Low Gluten Diets May Be Associated With Higher Risk of Type 2 Diabetes
There are many problems with this claim…first, this isn’t a study that is published…anywhere.
The “study” itself is filled with flaws, but none of the mainstream media outlets seemed to notice. All of them stuck with the narrative that was given. None questioned the veracity of the claims made.
The study comes from Harvard researchers, which may sound impressive, but they don’t always get things right. I’m not saying they are always wrong, but…Harvard “scientists” are largely to blame for the decades-long fear of fat trend that led people to believe that dietary fat causes disease. They also downplayed the role sugar plays in the development of heart disease.
An excerpt from my article Big Sugar Paid Harvard Scientists to Tell Big Fat Lies About Heart Disease summarizes the scandal:
In the 1950s, studies showing a link between coronary heart disease (CHD) and sugar intake started to emerge.
When the sugar industry (which many not-so-affectionately call “Big Sugar”) got wind of this not-so-sweet news, they paid scientists to downplay the link and promote saturated fat as the culprit instead.
Big Sugar paid Harvard scientists the equivalent of about $50,000 in today’s dollars to influence the review, and subsequently spent $600, 000 ($5.3 million in 2016 dollars) to teach “people who had never had a course in biochemistry… that sugar is what keeps every human being alive and with energy to face our daily problems.”
The studies used in the two-part review – which was published in the respected New England Journal of Medicine in 1967 – were handpicked by the sugar group.
Now, let’s define what gluten IS:
Gluten is a complex two-part protein found in grains such as wheat, rye, barley, and spelt. The two different proteins that comprise gluten are called glutelin and gliadin. Breads, cereals, and baked goods are obvious sources of gluten (unless they are labeled gluten-free), but they aren’t the only foods that contain the protein – it can be found in many items, even those you wouldn’t expect.
It is also important to explain a condition related to gluten called Celiac disease, because it is relevant to this story:
People who have celiac disease, a chronic autoimmune/inflammatory disorder, must avoid the consumption of gluten. Celiac disease originates in the gut, but affects the entire body when untreated. In people with celiac disease, the villi of the small intestine are damaged when gluten is consumed. When a person with celiac disease continues to eat gluten, serious health problems can develop, including neurological conditions, osteoporosis, other autoimmune disorders – and depression.
Now, back to this new “study” – let’s take a look at the flaws, and oh boy, there are many.
From the press release:
The researchers estimated daily gluten intake for 199,794 participants in three long-term health studies — 69,276 from the Nurses’ Health Study (NHS), 88,610 from the Nurses’ Health Study II (NHSII) and 41,908 from the Health Professionals Follow-up Study (HPFS) — from food-frequency questionnaires completed by participants every two to four years. The average daily gluten intake in grams was 5.8 g/d for NHS, 6.8 g/d for NHSII, and 7.1 g/d for HPFS, and major dietary sources were pastas, cereals, pizza, muffins, pretzels, and bread.
Over the course of the study, which included 4.24 million person-years of follow-up from 1984-1990 to 2010-2013, 15,947 cases of Type 2 diabetes were confirmed.
I hope you noticed a few red flags in that passage.
First, the researchers based their study on dietary recall questionnaires that were completed by participants. Those kinds of questionnaires are notoriously unreliable. The researchers “estimated” gluten intake based on those self-reported assessments.
This is casually mentioned in the press release:
Study participants reported their gluten consumption and the study was observational, therefore findings warrant confirmation by other investigations.
While their study size was massive -199,794 people is a lot – it still did not establish a cause-effect relationship.
At best, this kind of review can only suggest a potential association, but this particular study didn’t even achieve that (I’ll explain why later in the article).
In the Popular Science article Gluten-Free Diets Are Not Actually Linked to Diabetes, Sara Chodosh elaborates:
These large data sets are perfect for finding significant links between certain lifestyles and diseases. They’re not so great at finding causes—in that they cannot determine causality at all. For example, the data could tell you that there’s a statistically significant link between eating nuts and heart health, but it can’t tell you that eating nuts causes a healthier heart. It may be that people who eat nuts tend to exercise more, or that people who eat nuts also eat other foods that are good for the heart. Or maybe nuts really do directly improve your cardiac capabilities—we just can’t tell that from correlational data.
Let’s look at another passage from the press release:
In this long-term observational study, researchers found that most participants had gluten intake below 12 grams/day, and within this range, those who ate the most gluten had lower Type 2 diabetes risk during thirty years of follow-up. Study participants who ate less gluten also tended to eat less cereal fiber, a known protective factor for Type 2 diabetes development.
“Cereal fiber”? Why did they specify “cereal” fiber and not just…fiber?
It is an interesting choice of words, especially considering that the majority of the research supporting the benefits of dietary fiber come from epidemiological studies that link the consumption of fiber-rich fruits and vegetables with a lowered risk of certain diseases such as obesity, heart disease, and cancer (particularly colon cancer).
And, when tested in the lab, controlled intervention trials that simply add fiber supplements to an otherwise consistent diet have not shown these protective effects.
Fruits, vegetables, nuts, and seeds are all excellent sources of fiber, in varying degrees. In addition, they all naturally contain far more nutrients than cereal or other grain-based foods (especially the processed ones).
So, one can’t help but wonder why these “researchers” failed to point that out.
Also, why did Geng Zong, Ph.D, one of the researchers, say this?
“Gluten-free foods often have less dietary fiber and other micronutrients, making them less nutritious and they also tend to cost more. People without Celiac disease may reconsider limiting their gluten intake for chronic disease prevention, especially for diabetes.”
What does he mean by “gluten-free foods”? That is not specified in the press release.
I can’t help but wonder if this is intentionally misleading. Why not say something like, “People without Celiac disease (or heck, everyone) may consider consuming more fruits, vegetables, nuts, and seeds to increase their intake of dietary fiber and other micronutrients, and to prevent chronic disease and diabetes”?
This is strange, too: If the researchers truly believe that people who don’t consume enough “cereal fiber” might be at higher risk of developing diabetes, then why not recommend gluten-free grains that are high in fiber, like quinoa, amaranth, buckwheat, sorghum, gluten-free oats, and teff? Why did they specifically refer to “gluten intake?” Gluten itself is NOT a form of fiber – it is a protein.
Hmm. I wonder if the push to consume GLUTEN has anything to do with the fact that for Big Pharma and others who profit from unhealthy humans, type 2 diabetes is a goldmine.
Ironically, in 2016, Harvard shared a press release with the following headline:
Cost of Diabetes Hits 825 Billion Dollars a Year
Type 2 diabetes is largely caused by lifestyle factors – and is therefore avoidable, controllable, and even reversible in most cases.
For the majority of people, type 2 diabetes (and sometimes, type 1) is caused by the very dietary advice “experts” have been giving for decades, as Dr. Davis explains in Diabetes, Inc:
- Cutting dietary fat and cholesterol–as advised the U.S. Department of Health and Human Services, the USDA, the American Diabetes Association, the American Heart Association, and the Academy of Nutrition and Dietetics
- Increased consumption of grains–that raise blood sugar higher than table sugar, as also advised by the same agencies
- Big Food and the soft drink industry–who have made high-carb grain-based products and soft drinks the centerpiece of their business model, while paying the same above agencies/experts to divert attention away from carbs and sugar and advocate silly notions like “everything in moderation”
In fact, if you want to avoid type 2 diabetes, avoiding grains (and gluten!) altogether is a great idea!
Dr. Davis writes,
I’m sometimes accused of exaggeration when I say that conventional dietary advice to cut fat and increase consumption of “healthy whole grains” causes type 2 (as well as much type 1) diabetes. But I can say with complete confidence that any food that 1) raises blood sugar and insulin to high levels every time you consume it, 2) plays a dominant role in diet, 3) provokes inflammation via multiple mechanisms, 4) can trigger immune destruction of pancreatic beta cells that produce insulin, and 5) acts as an appetite-stimulant (via gliadin protein-derived opiate peptides and blockade of the leptin hormone) all adds up to an astoundingly powerful way to cause diabetes.
Speaking of diabetes and avoiding gluten, this is certainly interesting (emphasis mine):
Our group just published a research study that shows those with celiac disease are much less likely to get type 2 diabetes compared to people without celiac disease. This was an unexpected finding and to our knowledge is the first study looking at the prevalence of type 2 diabetes in celiac disease. While we found that people with celiac disease have substantial protection from type 2 diabetes, it’s not clear why. (source)
If those study participants were strictly following a gluten-free diet (as people with Celiac disease NEED to do), then…perhaps we can speculate that avoiding gluten is what protected them from developing type 2 diabetes.
It’s just an idea – an intriguing one, I think.
What else were the people who were studied eating, or not eating? That crucial bit of information is not shared with us.
Also – and this is a BIG problem – the researchers did not specifically 
study people on gluten-free diets. They only studied associations between eating less gluten and developing diabetes.
They even admit this in the press release:
Also, most of the participants took part in the study before gluten-free diets became popular, so there is no data from gluten abstainers.
The researchers claim a 13% difference in type 2 diabetes incidence, but that is minor, especially considering the inherent flaws associated with epidemiological studies. As Dr. William Davis explains, “…confident associations are typically much larger than this: 40% or 50%, for instance. This does not stop, of course, media people, who are journalists at best, paid marketing people for the grain industry at worst, to propagate their misinterpretations.”
As Chodosh points out:
It’s possible that gluten intake actually has nothing to do with diabetes risk, it’s that people who eat less gluten also eat less fiber, and the lack of fiber is what’s affecting the likelihood of getting diabetes. Maybe people who ate less gluten in the ’80s and ’90s also tended to eat worse overall. Maybe those people ate not just fewer whole grains, but also more sugar. Maybe gluten has nothing to do with it. We just don’t know yet.
All of this does raise an important question: COULD avoiding gluten lead to the development of type 2 diabetes?
Definitely – if you replace products that contain gluten with substitutes that are made with cornstarch, rice flour, tapioca starch, and potato flour. There are plenty of gluten-free junk foods on the market – cookies, brownies, cupcakes, crackers, chips, bagels, breads, pancakes, waffles, muffins – you name it, you can probably find a gluten-free version. Of course, many of these “food” items are also filled with sugar…and I think by now everyone knows sugar is linked with the development of type 2 diabetes (and a long list of other chronic, debilitating diseases).
Another deceptive claim…
In the beginning of the press release, the researchers make the claim that there “is lack of evidence that reducing gluten consumption provides long-term health benefits.”
I guess they haven’t been keeping up with research.
Maybe they should take a look at these studies…
Intestinal cell damage and systemic immune activation in individuals reporting sensitivity to wheat in the absence of coeliac disease (My article on this study: Trust Your Gut: Now There’s Proof That Non-Celiac Gluten Sensitivity Exists)
Non-celiac Gluten Sensitivity and Rheumatic Diseases
New study links protein in wheat to the inflammation of chronic health conditions
The Dietary Intake of Wheat and other Cereal Grains and Their Role in Inflammation
Diagnosis of Non-Celiac Gluten Sensitivity (NCGS): The Salerno Experts’ Criteria
There are many more.
Parting thoughts
Many people believe that “gluten free” is a silly diet trend and that there’s not a thing wrong with consuming products that contain gluten. It’s become fashionable to mock and belittle people who don’t have an official Celiac diagnosis, but decide to live a gluten-free lifestyle anyway.
But Celiac disease isn’t the only problem associated with gluten. Some have wheat allergies, and now researchers are trying to determine how to best diagnose people with a recently identified condition called Non-Celiac Gluten Sensitivity.
From the paper Spectrum of gluten-related disorders: consensus on new nomenclature and classification:
It is now becoming apparent that reactions to gluten are not limited to CD, rather we now appreciate the existence of a spectrum of gluten-related disorders. The high frequency and wide range of adverse reactions to gluten raise the question as to why this dietary protein is toxic for so many individuals in the world.
I have a few thoughts on this…
One: Why do those people care what other people eat/don’t eat? Is it somehow a threat to them?
Two: Why would people voluntarily restrict their diets if they weren’t actually feeling better and noticing improvements in health? I am one of the people who feels infinitely better on a gluten and grain-free diet, and I know many others.
Three: Products that contain gluten are not necessary for health anyway. There’s not a thing in them that you can’t get from other dietary sources.
Four: So what if there are a lack of studies that “prove” a particular food/ingredient is “bad” for us? Does it really matter? If a person feels better on a certain kind of diet, who is anyone else to say they are wrong?
In the article How to Avoid Clickbait on Nutrition Studies, Kamal Patel writes…
You don’t need a study for everything.
This cannot be repeated enough. Let’s say that you have a friend who SUPPOSEDLY developed a allergy to red meat a few years ago. But instead of it happening within minutes of eating the food, like a normal allergy, it happens hours after. Ridiculous! Preposterous! And there weren’t any studies on this supposed allergy when you looked it up … so it must be psychosomatic.
Wrong. Studies started being published in the last few years of red meat allergies caused by tick bites.
Humans are so sure of their limited cognitive abilities that they’ll disregard anything that doesn’t fit into their predefined mold. If someone reliably gets an allergic reaction after eating red meat, that’s a very valuable observation, and the starting point for further thought. It’s not something that has to be backed up by a study, because studies aren’t always available for what’s happening to you.
The body is infinitely more complex than we understand, and isolated trials will never be able to answer all the questions we want to know about. Your personal experiences are worth as much, and sometimes more, than the studies that are out there.
What does this mean for you?
If you believe you may have celiac disease, it is important to consult with your healthcare provider because of the seriousness of the disorder. If you don’t think you have celiac disease, but believe you might benefit from avoiding gluten, it couldn’t hurt to try. Humans don’t NEED to consume gluten, and many people report feeling better after going gluten-free. Just be sure to avoid gluten-free junk foods.
For those who are still skeptical (or want inspiration), please read my dear friend Melissa’s personal story about her battle with NCGS and the amazing health transformation she experienced when she removed gluten from her diet.
Let this study be a cautionary tale: always, always read press releases and associated articles with a critical eye.
Related Reading
Trust Your Gut: Now There’s Proof That Non-Celiac Gluten Sensitivity Exists
Can Gluten-Free Diets Help Tame Psoriasis?
Myths, Misconceptions, and Outright Lies About Nutrition Are Keeping People Fat and Sick
Depression Cause May Be Physical, Not Mental
Cancer, the Media, and the Misinterpretation of Studies: A Cautionary Tale
Lisa Egan Runs Nutritional Anarchy, where this article first appeared, and appears here with permission.
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