Another study was released recently that purports to “prove” that gluten-free diets are associated with increased risk for type 2 diabetes. As with many studies of this type, the findings were misinterpreted but fed into the media’s continual need for titillating headlines. I thought this hubbub would pass by now, but reports about this study (such as this piece of tripe from The Washington Post) seem to be gaining more traction than usual, fueling the misunderstanding and misinformation that plagues nutritional thinking. While I thought this would just pass, it looks like it will not and I’m therefore posting my comments.
First, a few words about epidemiological studies of the sort this group used, the Physicians’ Health Study population of health professionals. The participants were asked diet questions, then health status was tracked over several years. Putting aside the imprecision of such dietary recall questionnaires, we know that such studies simply cannot—no matter how large the study, no matter how meticulous the questions—establish cause-effect relationships; they can only suggest a potential association. The purported 13% difference in type 2 diabetes incidence is minor, given the dramatic imprecision of epidemiological studies; 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.
To further illustrate the problems inherent in epidemiological studies, let’s pretend that we want to establish whether a Toyota Prius is a safer car to drive than a Corvette. We therefore identify 1000 Prius drivers and 1000 Corvette drivers. We then ask the drivers every year whether they’ve had a car accident. What if we observe that people driving Corvettes are 30% more likely to have a high-speed car accident and 18% more likely to die in the accident? By these observations, should we conclude that Corvettes are far more dangerous cars than Priuses? Of course not. (I made these figures up, of course, just to illustrate, though I wouldn’t be surprised if such numbers approximate the real-life situation.) We can only say that there is an association between driving a Corvette and more accidents and fatalities. But we can most definitely NOT say that the increased dangers are due to the car per se, because it might be due to 1) the kinds of people who buy Corvettes (speed-hungry males), who are more likely to 2) drive aggressively, 3) drink and drive, and 4) ignore laws not to text or engage in other risky activities while driving, etc. You get the picture–it may have nothing to do with the car itself, even though there is an apparent association. But outlets like The Washington Post and others can still make ridiculous headlines claims like “Corvettes found to kill drivers.”
So it goes with trying to track the consequences of consuming more or less gluten. Reduced “gluten” consumption can be a marker for:
- Increased consumption of gluten-free foods made with cornstarch, rice flour, tapioca starch, and potato flour. I have discussed the dangers of these awful gluten-free replacements many times, as they are clearly associated with increased risk for type 2 diabetes, weight gain, inflammatory conditions, heart disease, cancer, and dementia. Sadly, most people who reduce or eliminate gluten gravitate towards such horrible replacement foods that yields an apparent association that cutting gluten increases type 2 diabetes.
- Reduced prebiotic fiber intake–Despite all the toxic components of wheat and grains, there is actually something good in them: prebiotic fibers. The average person obtains around 2-4 grams per day of the prebiotic fibers, arabinoxylan, amylose, and others, from fibers in grains, in addition to inert cellulose fibers. Reduced gluten is therefore a marker for a reduction in prebiotic fiber intake. This is what happens to the majority of people on low-carb, Atkins, and paleo diets if they are not informed about the importance of including plentiful prebiotic fibers in their daily diet. Obviously, you can easily compensate for the removal of grain-sourced prebiotic fibers by increasing consumption of legumes, root vegetables, and other sources. Because the concept of prebiotic fibers is so new, very few people have had a chance to take advantage of this strategy and it therefore will not show up in this epidemiological analysis, instead yielding the apparent low-gluten/more diabetes association.
Those two factors, in addition to other potential unidentified factors that can plague such study design and can only be speculated on, make it impossible to conclude that reduced gluten leads to increased type 2 diabetes or that increased gluten prevents diabetes. Yet that is what was reported.
If we believe the interpretations of the findings offered by the authors of the study, as well as by the generally naive media, then it appears that gluten or some other component of grains are therefore protective against developing type 2 diabetes. Of course, outside of prebiotic fiber intake associated with gluten intake, this is absurd—no such science exists.
The Washington Post, as well as the researchers themselves, were not the only people to misinterpret the findings so tragically. Fox News, ABC News, Boston Magazine and many others made the same absurd blunders. In fact, this silly piece of epidemiological semi-fiction received such favorable treatment in the media that it makes me wonder if there was some sort of financial catalyst, AKA the grain lobby, involved. I don’t know, but it looks and smells an awfully lot like a smoking gun.
I am really glad you addressed this. I read the article in WP and just assumed that the study did not account for the probability that people shifted from gluten-bearing grains to other processed foods using high carb grains such as corn. I feel like the media and public take particular evil joy in denouncing gluten-free–and refuse (or don’t know enough) to discriminate between grain free, low carb, and ingestion of unprocessed vegetables, proteins, fats, and fiber vs carb loaded gluten-free processed foods.
I can understand why the wheat industry promotes disdain for the grain free diet, but I don’t understand why so many regular people are openly disdainful. It is almost as if they want to knock my healthy eating (and I stay away from talking about it unless asked) to justify their love of processed high carb food–their addiction.
Anyway, thanks for being a voice of reason and positivity.
Which gluten free flours should we be trying to eat? I am in the U.K. And love this bread from Genius .
These are the Ingredients
Water, Maize Starch,Potato Starch, Mixed Seeds: Sunflower Seeds (4%), Linseeds (3%), Millet Seeds, Poppy Seeds (1%); Tapioca Starch, Rapeseed Oil, Humectant: Vegetable Glycerol; Psyllium Husk Powder, Yeast, Stabilisers: Hydroxypropyl Methyl Cellulose, Xanthan Gum; Ground Golden Flaxseed, Free Range Dried Egg White, Rice Flour, Fermented Maize Starch, Dextrose, Iodised Salt: Salt, Potassium Iodate; Partially Inverted Sugar Syrup, Calcium Carbonate, Niacin, Iron, Riboflavin, Thiamin, Folic Acid.
You want to eat that with all those ingredients! Why not try just eating food that has one ingredient? Broccoli, cabbage, egg, cream, butter etc.
Sarah wrote: «Which gluten free flours should we be trying to eat?»
Other than the Wheat Belly all-purpose baking mix, I’m not aware of any commercial mixes that are safe.
re: «…bread from Genius. These are the Ingredients…»
Maize is corn. In addition to being a high glycemic grain, it also contains an adverse protein (zein), and some risk of pesticide uptake, or being a pesticide in the case of Bt GMO corn.
Rice Flour, in addition to being a high glycemic grain, contains the adverse lectin wheat germ agglutinin, and depending on your national standards, is at some risk of high arsenic content.
Maize Starch, Potato Starch, Tapioca Starch, Rice Flour, Dextrose and Partially Inverted Sugar Syrup might as well be sugar, or actually are sugar. This is the top problem with most gluten-free products today.
Hydroxypropyl Methyl Cellulose and Xantham Gum are emulsifiers, and suspect gut flora antagonists.
Calcium Carbonate is an inappropriate form of something we don’t want to be supplementing anyway (calcium – get it from real food).
Iron and Folic Acid are fortification doubtless required by your national nutrition nannies, but they are inappropriate for a non-trivial fraction of the population.
The other ingredients are mostly harmless.
re: I am in the U.K. And love this.
The product was likely formulated with a primary goal of eliciting that reaction, and not in any consideration of your health, apart from not being instantly fatal to those with celiac disease.
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I am very happy that Dr. Davis wrote this blog post. I did not know about this research and media article until last night when I was at the gym. One couple who just started on the WB lifestyle told me about the article and said that they were doing it all wrong because the research now says gluten-free diets cause type-2 diabetes. Since I had not seen the article, I looked at them strangely and told them the likely cause of that was because people who ate gluten-free foods were likely consuming foods high in rice flour, tapioca starch, etc. I said they should stay on the WB lifestyle because it does work (they are diabetic with big belies) and that they should not buy foods labelled gluten-free and just stick to self-prepared single-ingredient foods. It is very disheartening to see such flawed research be produced and then propagated in the media. I also agree with Janine’s post that it seems that people want to discourage grain-free diets so they can justify their addiction to grain-based foods.
Keep doing what you’re doing, Dr. Davis – I bought so many copies of your book to give to family and friends … I am confident that eventually more people will be saved.
Jay
One additional comment. Even assuming that the study was remotely scientific, which it clearly wasn’t, when the study found people who fell into the two groups, a gluten-free group (that is, a group which had for some reason, chosen to go GF) and a standard American Diet group (AD), they did not investigate or analyze further into possible variables. One leaps to mind: the GF group might be a group in chronic ill-health, overweight, poor diet, so that they were, to put it mildly, unhealthy at the start. Because they were unhealthy they might have been more likely to go GF. I know very few people who went running to GF because they felt like a million dollars. They go there because the American diet is slowly killing them. The other group, fit and healthy with little dietary or weight issues might have been the AD group. So, measure an already “ill” group against a “nothing is wrong” group and what do you think you will find? [Every once in a while someone posts a study that says slightly overweight people are healthier than thin people, live longer, etc. What they don’t say is that, within that group of “thin” people, are people who are thin because their health is really poor.]
A coworker says she takes raw unfiltered apple cider vinegar as a prebiotic. Is raw unfiltered apple cider vinegar a good source for prebiotics?
Mike Panella wrote: «Is raw unfiltered apple cider vinegar a good source for prebiotics?»
It doesn’t appear so. Looking at the Nutrition Facts label for Bragg’s, the total carbohydrate content is nil, and they don’t even list fiber carbs – no fiber carbs means no prebiotic fiber.
It also may not have any direct probiotic value, although it’s being studied for that. The live Acetobacter aceti bacteria in the “mother” aren’t presently considered essential for gut flora. ACV contains none of the Lactobacillus or Bifidobacteria species we seek.
Nonetheless, ACV may have a role. It’s used in several Wheat Belly recipes, and is specifically mentioned in:
Gastrointestinal Recovery After The Wheat Battle Is Won
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Raw Apple Cider Vinegar is overrated. People are promoting it as a cure-all, which it is likely anything but. I do use it, but for taste and not hype. I don’t think there’s any prebiotic content in ACV.
I saw the headlines and immediately thought, “Well, sure, if you start building your diet around gluten-free bread, pasta, cookies, donuts, etc. Potato starch, corn starch, rice flour and tapioca flour ain’t exactly low GI.
Pardon me while I go make lamb burgers with an asparagus salad on the side.
It never ceases to amaze me the lengths people go to in order to substitute the foods that they are unable eat or have decided not to eat. Is this some kind of physiological condition? I cite vegetarians who seem to need ‘veggie sausages’, celiacs and people who have allergies around bread and cereals who seek out the same products supposedly ‘free from’. If you can’t tolerate bread then don’t eat it in any form. If you are allergic to nuts don’t eat nuts, if you are diabetic you cannot tolerate high GI carbohydrates so don’t eat them. Why are people duped by junk food manufacturers who use wholesome sounding product names to promote rubbish ‘food’.