Link Between Gluten and Obesity Challenges “Classic” Picture

Historically, medical textbooks have presented Celiac disease patients as small, thin, anemic individuals–a depiction that still dominates many physicians’ views of gluten intolerance and the people who have it.

Recent research, however, is forcing a major re-thinking of that “classic” picture, and urging clinicians to be on the lookout for gluten sensitivity among people who are overweight or obese.

Described variously as an autoimmune disease or an allergy, Celiac disease affects the small intestine by reducing its total surface area. In sensitive individuals, presence of gluten in the gut instigates an inflammatory response, which over time destroys the fingerlike villi lining the inside of the small bowel.

Because the villi comprise most of the bowel’s surface area, damage caused by chronic inflammation can shrink the intestinal surface area–typically about the size of a major league baseball field, down to the size of an infield. This severely compromises the bowel’s ability to absorb nutrients. Micronutrient absorption is particularly compromised, meaning that gluten-sensitive people are usually deficient in iron, calcium, and other minerals absorbed via the gut.

Previously, problems with absorption were thought to result in the short stature, low body weight, and tendency towards anemia that characterize the classical description of Celiac disease.

A Surgeon’s View

A new understanding of gluten sensitivity suggests that the core issue is still one of malabsorption – but rather than inhibiting weight gain, the lack of nourishment instead motivates a drive to eat excessively.

One physician questioning the old image of gluten sensitivity is Phoenix, AZ-based bariatric surgeon, Terry Simpson, MD.

After years of working with gastric bypass surgery patients, Dr. Simpson noticed that many continued to suffer from chronic iron and calcium deficiencies following surgery. When no amount of iron or calcium supplementation seemed to help, he went back to take a closer look at the distal biopsy specimens he’d collected from their original surgeries.

He was struck when he found horribly flattened villi in most of these samples. Quickly he realized that this meant their ability to absorb nutrients had already been compromised long before undergoing surgery.

He said that many overweight individuals believe they have some type of intestinal disorder like irritable bowel syndrome or a “sensitive” stomach. They can tell from their own experience that something is not right with their digestive systems, but they don’t really know what.

Suspecting that undiagnosed gluten intolerance could be the true cause of their perceived bowel disorders, Dr. Simpson began putting his patients on a six-week gluten-free diet after surgery.

He finds that generally speaking, they feel better and have increased energy. The diet seems to positively impact their absorptive abilities; by doing nothing other than switching to gluten-free eating, his patients’ iron levels usually normalize and their anemia starts to resolve.

GF Diet Promotes Weight Loss

Surprised by these results, Dr. Simpson wondered how patients would fare if they adopted a gluten-free lifestyle before undergoing surgery.

He identified groups of morbidly obese patients whose preoperative labs indicated iron deficiency. Taking advantage of the six months during which insurance covers a pre-op, medically supervised diet, he asked them to go gluten-free.

In addition to resolving their anemia, those patients who eliminated gluten lost significantly more weight than those on the standard 1,800-calorie pre-surgery diet. Amazed by how much better they felt, the gluten-free patients also recovered from surgery more rapidly than those on the standard diet.

Increasingly, Dr. Simpson’s patients appeared to represent an important variant of the stereotypical image of gluten intolerance and celiac disease, so much so that he now recommends that all his bariatric patients get tested for gluten intolerance.

Even if the tests are negative, he still urges his patients to eat gluten-free for six weeks just to see how they feel. After six weeks, he asks them to eat a single Wheat Thin cracker. Among the gluten-sensitive, he says, “every one can tell you, that was the worst thing I ever ate.”

Dr. Simpson is not alone in advising gluten testing; the suggestion that “all patients candidate for bariatric restrictive or malabsorptive-combined surgery undergo Celiac disease screening tests prior to any surgical treatment” is becoming more widespread among obesity treatment providers (de’Angelis, et al. Obes Surg. 2012; 22: 995–996).

The Changing Shape of Gluten Sensitivity

When Celiac disease was first outlined in the medical tomes of the late 19th and early 20th century, the vast majority of people did not have access to the wide array of foodstuffs that we do today. During the Great Depression or World Wars I and II, food portions were much smaller and, consequently, obesity was rare.

“In those times,” Dr. Simpson explains, “if you ate a little plate of food and couldn’t absorb it, you were going to be thin.”

Contrast this to our modern food landscape of unlimited pasta bowls, where we can easily walk into most restaurants and order a salad with enough calories to fuel us for an entire day.

Even when the villi of the small bowel are damaged, as is the case in gluten-sensitive people, specialized cells in the large intestine can still absorb countless calories in the form of macronutrients like glucose. In order to take in adequate amounts of essential micronutrients, overweight individuals may have to consume a huge quantity of calories, which appears to be a potential cause of obesity.

Surrounded by mountains of cheap, processed foods, most people can now readily consume an unlimited amount of calories. Paradoxically, while many processed foods are fortified with vitamins and minerals, our bodies will absorb the macronutrients long before they absorb the micronutrients – leaving us overfed, yet undernourished.

In today’s food world, it’s not difficult for anemic individuals with uncontrolled gluten disease to acquire inexpensive double-decker hamburgers – from which they’ll take in plenty of calories, but won’t absorb the iron that their bodies so desperately need.

Cooking as Clinical Intervention

Dr. Simpson recommends a simple solution to the dual challenges of obesity and gluten sensitivity: teach people how to cook.

“When you get patients to cook,” he explains, “it takes a whole bunch of problems out of their diet.” Learning to prepare fresh, healthy, gluten-free meals at home eliminates potential allergens and reduces the amount of processed foods that one consumes. It also offers greater control over portion sizing, flavors, and food-related expenses.

Even for those who are profoundly impressed by their results, the transition to a gluten-free lifestyle can be challenging. Dr. Simpson has found that for most of his patients, the change is far easier to sustain when they avoid packaged products and favor home cooking over eating out.

While not everybody is gluten intolerant, and it’s certainly not the universal cause of obesity, we can all benefit from cooking our own food, Dr. Simpson believes. Rather than performing surgery, the most valuable service he offers to his patients is culinary education. “I spend more time teaching them how to cook than I do operating on them now.”

In some cases, surgery may still be necessary for patients who are really struggling to lose weight. But converting to a home cooked, gluten-free diet can ease the process – or perhaps even eliminate the need for surgery altogether.


Kristen Schepker holds a Master’s degree in Integrative Health Studies from the California Institute of Integral Studies. She is a certified yoga instructor and holistic health and wellness coach practicing in San Francisco, CA.

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