BRIDGING THE GAP
RESEARCH and PRACTICALITY
To Wheat or Not to Wheat – A case for or against a gluten-free diet
The popularity of a gluten-free diet has increased dramatically in recent years, as evidenced by the rapidly-expanding $2.5 billion market for gluten-free products ( 1 ). Adoption of a gluten-free diet and use of their products are endorsed by slender, radiant celebrities like Gwyneth Paltrow, Julia Roberts, and Miley Cyrus who claim that eliminating gluten will improve skin, increase energy levels, and (most tantalizing) melt the pounds away. Gluten-free alternatives to everything from breads to protein bars have invaded store shelves, imparting the widespread conception that gluten-free foods are healthier alternatives to foods that contain gluten; yet most consumers are only superficially aware of what gluten is and what necessitates the adoption of a gluten-free diet. Contrary to popular belief, there is no published scientific evidence that gluten-free diets impart benefits to healthy individuals. In fact for the general population gluten-free diets may negatively impact health and weight (2-4).
Most people associate gluten with baked good containing wheat, but the scope of gluten-containing foods is much larger than simply baked goods. Gluten is a protein found in wheat, rye, and barley that was introduced to the human diet about 10,000 years ago with the advent of food cultivation during the agricultural revolution. A small portion of the population suffer distress after ingesting gluten due to differences in evolution (1). Because gluten is found in most processed foods and in foods made with gluten-containing cereals, the list of off-limit foods in a gluten-free diet is extensive including: prepared lunch meats, sausages, fried food, condiments (soy sauce, dressings, bouillon cubes), beer, hot chocolate, root beer, prepared/canned fruits and vegetables in sauces or syrups, and most processed foods (5).
Gluten avoidance is necessitated in a very small portion of the population that react adversely to gluten. Celiac disease, thought to affect 1% of the population, is an autoimmune disorder that damages the small intestine after the ingestion of gluten. Symptoms include chronic diarrhea, weight loss due to malabsorption of nutrients, anemia, and osteoporosis (1). The strict adherence to a gluten-free diet is the only treatment for Celiac disease (1, 4). Other reactions to gluten include wheat allergy (the ingestion of wheat causes an allergic reaction that affects skin, the gastrointestinal tract, or the respiratory tract) and gluten sensitivity. Gluten sensitivity has only recently been recognized by the medical community because it has no means of scientific diagnosis; sufferers of gluten sensitivity often have the same symptoms as those with celiac disease but without the damage to the small intestine. Gluten sensitivity is diagnosed by ruling out celiac disease and wheat allergy (both of which can be determined through medical tests) and noticeable improvement of symptoms after the elimination of gluten (1). Those affected with adverse effects in response to gluten consumption necessitate the adoption of a gluten-free diet, but there is no reason for healthy individuals to eliminate gluten in hopes of health benefits. Gluten-free diets may cause adverse health effects in the general population because they are often not nutritionally balanced (6). In fact, one study showed that half of celiac sufferers, who must adhere to gluten-free diets to avoid small intestine damage, suffer from deficiencies that may contribute to cardiovascular disease development (7). Contrary to popular belief, gluten plays an important role in digestive health, aids in the prevention of chronic diseases, and encourages weight loss (4).
The Danger of Eliminating Gluten
The internet is littered with websites decrying the evils of gluten and claiming that the elimination of gluten can “be of great benefit to those wishing to lose weight” and will “increase energy levels, lower bad cholesterol levels and even assist the body’s digestive processes” (8). Such claims are not supported by cited scientific research and are rationalized by the belief that gluten-free diets are low in carbohydrates and that the consumption of unhealthy processed foods is eliminated; however due to the growing gluten-free product market, gluten-free processed foods are readily available. Such gluten-free products are often higher in calories, fat, and sodium and lack the satiety-inducing fiber of their gluten-containing counterparts. In fact, there is no published scientific evidence that suggests gluten-free diets are beneficial for the general population (4).
Eliminating gluten-containing cereals like wheat, rye, and barley can cause nutritional deficiencies in folate, iron and dietary fiber because gluten-free products are often made from refined grains (9). Deficiencies are especially prone to those who eliminate nutritional whole grains, like whole wheat flour, and replace them with refined gluten-free products like potato flour or white rice flour (6). The refining process removes the outer layer of grains where most of the fiber and many nutrients are contained.
Gluten-free products often contain higher levels of saturated- and trans- fatty acids than gluten-containing products (2). Saturated and trans fats have been shown to increase the chance of developing chronic diseases like cardiovascular disease, type 2 diabetes, and obesity (10, 11). In a study of 28,100 women in the US without cardiovascular disease or cancer, saturated and trans fats were associated with increased risk of high blood pressure (a contributing factor to heart attacks and strokes) during 12.9 years of tracking (10). Another study of 85,095 women revealed a direct relationship between trans fats and higher risks of coronary heart disease (11). Gluten-free products often contain more fat, sugar and sodium and consequently should not replace gluten-containing products unless necessitated by a medical condition.
Benefits of Gluten
Gluten-containing whole grains like wheat, barley, and rye are shown to increase beneficial gut bacteria, protect against cardiovascular disease, protect against certain cancers, and aid weight loss (3, 4, 1214-). A study that looked at the effect of a gluten-free diet on gut bacteria suggests that the elimination of gluten upsets the balance of intestinal bacteria which may lead to a weakened immune system. Bacteria in the intestinal tract are largely influenced by their environment, particularly the ingestion of carbohydrates. Since switching to a GFD often causes a decrease in polysaccharide (starch and fiber) intake, one of the main food sources for beneficial bacteria, other types of bacteria (like E. coli) may increase (3).
Whole grain intake (such as whole wheat, barley, and brown rice) has also been shown to decrease systolic and diastolic blood pressure, reducing the risk of hypertension, heart attack and stroke (12, 14). The argument to consume gluten-containing foods is further strengthened by a study of 61,433 Swedish women that whole grain consumption, particularly of rye, may reduce colon cancer risk (13).
The fiber in whole grains also increases satiety, in turn reducing caloric intake and aiding in weight loss (4). Contrary to popular belief that carbohydrates lead to weight gain, the intake of whole grains supplies essential nutrients, fuel for the body, and fiber to curb appetite and facilitate weight loss (4).
There is no scientific evidence that eliminating gluten from the diet will contribute to weight loss. Possible weight loss can be explained by the elimination of unhealthy processed foods that are off limits since they contain gluten; however, any resultant weight loss is not due to the absence of gluten but to the emphasis on whole, fresh foods. Thanks to the rapidly growing gluten-free market, products that attempt to mimic off-limit processed foods are not healthier simply because they are gluten-free. In fact, the gluten-free parallel products are often higher in fat, sugar, and salt in order to compensate for the lost flavor that result from excluding gluten. Therefore, simply replacing processed foods containing gluten with gluten-free processed foods may result in weight gain and contribute to stroke, cardiovascular disease, type 2 diabetes, and obesity. For those without wheat allergy, celiac disease, or gluten sensitivity there is no need to exclude gluten. In fact, the exclusion may have detrimental health effects. If weight loss is the desired goal, focus on natural, low energy foods (vegetables and fruits), whole grains full of fiber and nutrients (wheat, quinoa, barley, brown rice), and legumes (beans, lentils). For individuals without adverse reactions, gluten is a healthy part of the diet.
Written by Anna Gregor with Eric Sternlicht PhD, Occidental College, Los Angeles, CA.
1. Sappone, Anne, Julio C. Bai, Carolina Ciacci, Jernej Dolinsek, Peter HR Green, Marios Hadjivassiliou, Katri Kaukinen, Kamran Rostami, David S. Sanders, Michael Schumann, Reiner Ullrich, Danillo Villalta, Umberto Volta, Carlo Catassi, and Alessio Fasano. "Spectrum of Gluten-related Disorders: Consensus on New Nomenclature and Classification." BMC Medicine 2012 (2012): n. pag. Print.
2. Caponio, Francesco, Carmine Summo, Maria Lisa Clodoveo, and Antonella Pasqualone. "Evaluation of the Nutritional Quality of the Lipid Fraction of Gluten-free Biscuits." European Food Research and Technology 227.1 (2008): 135-39. Print.
3. De Palma, Giada, Inmaculada Nadal, Maria Carmen Collado, and Yolanda Sanz. "Effects of a Gluten-free Diet on Gut Microbiota and Immune Function in Healthy Adult Human Subjects." British Journal of Nutrition 102.08 (2009): 1154. Print.
7. Hallert, C., C. Grant, S. Grehn, C. Granno, S. Hulten, G. Midhagen, M. Strom, H. Svensson, and T. Valdimarsson. "Evidence of Poor Vitamin Status in Coeliac Patients on a Gluten-free Diet for 10 Years." Alimentary Pharmacology and Therapeutics 16.7 (2002): 1333-339. Print.
10. Wang, L., J. E. Manson, J. P. Forman, J. M. Gaziano, J. E. Buring, and H. D. Sesso. "Dietary Fatty Acids and the Risk of Hypertension in Middle-Aged and Older Women." Hypertension 56.4 (2010): 598-604. Print.
12. Behall, K., D. Scholfield, and J. Hallfrisch. "Whole-Grain Diets Reduce Blood Pressure in Mildly Hypercholesterolemic Men and Women." Journal of the American Dietetic Association 106.9 (2006): 1445-449. Print.
13. Larsson, S. C., E. Giovannucci, L. Bergkvist, and A. Wolk. "Whole Grain Consumption and Risk of Colorectal Cancer: A Population-based Cohort of 60?000 Women."British Journal of Cancer 92.9 (2005): 1803-807. Print.
14. Tighe, P., G. Duthie, N. Vaughan, J. Brittenden, W. G. Simpson, S. Duthie, W. Mutch, K. Wahle, G. Horgan, and F. Thies. "Effect of Increased Consumption of Whole-grain Foods on Blood Pressure and Other Cardiovascular Risk Markers in Healthy Middle- aged Persons: A Randomized Controlled Trial." American Journal of Clinical Nutrition 92.4 (2010): 733-40. Print.