Do you eat gluten-free?
If so, do you have celiac disease, or do you prefer to avoid gluten because you—like many other people—have found that you just feel better without it? Maybe your skin is clearer when you stay away from gluten, or you have fewer headaches, your moods are more stable, and your digestion and elimination (your poo!) are better. You know you feel better without gluten, but what if a study by Harvard researchers said, “the avoidance of gluten may result in reduced consumption of beneficial whole grains, which may affect cardiovascular risk. The promotion of gluten-free diets among people without celiac disease should not be encouraged.” Would you go with your gut (no pun intended), or would you take their word for it and ditch your gluten-free diet?
Let’s take a closer look at this. To be fair, some people are becoming overly and unnecessarily “afraid” of gluten. The growing popularity of Paleo diets as well as low-carb and ketogenic diets has put the potential negative impacts of gluten consumption front and center on people’s radar like never before. (Even though the latter two diets are not by definition gluten-free.) And while gluten does negatively impact people who don’t have celiac disease, but who have a milder form of gluten sensitivity, this doesn’t mean that everyone should avoid gluten on principle. For people who experience no adverse effects from consuming gluten, there’s no need to go out of their way to avoid every molecule of this grain-based protein. Some might enjoy a bagel or slice of pizza now and then, and they don’t need to worry about cross-contamination in restaurants or at social functions. So the demonization of gluten might indeed be going too far, but that doesn’t mean it’s completely benign—let alone protective—for everyone without celiac disease.
First of all, the study in question (published in BMJ, formerly the British Medical Journal) was an epidemiological survey. What this means is, researchers took data from food intake and tried to find associations between consumption of those foods and a particular health outcome. This study—like many others in nutrition research—was based on food frequency questionnaires (FFQs). There are different versions of FFQs, but they usually ask people to recall how much of a particular food they consumed over some defined period of time, or how often the food was consumed. Sometimes these questionnaires require people to think about their food intake going back years. If you can’t remember what you had for lunch five days ago, you’ll have some appreciation for how sketchy this data typically is. FFQs are unreliable at best, and at worst, they’re just plain useless. Epidemiological data can be used to generate hypotheses, but not to prove cause and effect. For example, the traditional Okinawan diet was rich in pork fat and sweet potatoes, and the Okinawans are renowned for their health and longevity. But unless we do far more precise clinical experiments, there’s no way to know whether the pork fat and sweet potatoes caused the Okinawans to have long, healthy lives. (Same goes for olive oil in the Mediterranean diet.)
So, regarding the food frequency questionnaires in the BMJ study, who consumed gluten? Who avoided it completely? Who ate only small amounts of it, and who ate wheat every chance they got? Who ate gluten and didn’t even realize it (hidden in sauces, marinades, etc.)? What else did they eat, and how much, how often? We can never really know what people eat unless they’re sequestered in a metabolic ward, where every morsel of food is weighed and measured, and the subjects have no access to any other food.
The study authors claim that people who follow a gluten-free diet might reduce their intake of whole grains, and a reduction in whole grain consumption might increase risk for cardiovascular trouble. Really? It could easily be argued that if people replace the gluten containing items with nutrient-rich non-starchy vegetables, quality proteins and healthy fats, they could just as well decrease their cardiovascular risk.
What, exactly, are these researchers afraid of? That individuals living with obesity, type-2 diabetes, and other effects of insulin resistance might do themselves harm by avoiding whole grain bread, pasta, muffins, fiber bars and breakfast cereal? There is nothing—not a single vitamin or mineral—present in gluten-containing grains that cannot be obtained from animal foods and non-grain plant foods, usually with a much lower glycemic impact, which is key for turning the tide on the exploding worldwide “diabesity” epidemic.
To its credit, BMJ published a well-written rebuttal to the study, whose authors noted, “Indeed, hominins consumed a grain-free diet from 2.6 million years ago to about 12,000 years ago, so it is highly unlikely that a gluten-free diet or Paleolithic diet is going to kill anyone long-term. In fact, grains are not essential, and contain no nutrient that cannot be obtained from other plant foods. Thus, it can be safely concluded that, whether gluten-free diet is indicated or not, it is not detrimental to avoid gluten.” Hard to say it any more clearly than that.
Bottom line: trust yourself. You know your own body better than anyone. If you feel better when you avoid gluten, don’t second-guess yourself based on scaremongering headlines.
- Lebwohl B et al. Long term gluten consumption in adults without celiac disease and risk of coronary heart disease: prospective cohort study. BMJ. 2017 May 2;357:j1892.
- Pijak M, Szantoova K, Vyjidak J. Letter to the editor: Are gluten-free diets among people without celiac disease „mass murder“? Re: Long term gluten consumption in adults without celiac disease and risk of coronary heart disease: prospective cohort study. BMJ 2017;357:j1892
- Catassi C, Bai JC, Bonaz B, et al. Non-Celiac Gluten Sensitivity: The New Frontier of Gluten Related Disorders. Nutrients. 2013;5(10):3839-3853.
- David Brady