Going gluten-free is an ever-so-mockable decision, despite the fact that an estimated 18 million Americans suffer from some kind of gluten sensitivity that results in embarrassing and painful symptoms like gas, bloating, constipation and urgent diarrhea.
Unlike celiac disease, which is an autoimmune disorder that damages the small intestines if gluten is present, there’s no blood test to confirm gluten sensitivity -- which contributes to even more skepticism about the condition. Gluten-free diets undertaken by people without celiac disease have been called the “new, cool eating disorder” or, more seriously, have been accused of helping troubled people mask other eating disorders.
But emerging research shows that at least some of the millions of people who are keeping the $10 billion-dollar gluten-free industry afloat may actually have a serious medical condition known as an intolerance to Fermentable Oligo-Di-Monosaccharides and Polyols (FODMAP, for short) -- specific types of carbohydrates found in all different kinds of foods, including certain fruits and vegetables.
Treating both non-celiac gluten sensitivity and FODMAP intolerance calls for eliminating wheat, barley and rye from the diet, but for very different reasons. Cutting those grains out can help gluten sensitivity sufferers because it removes gluten, a type of protein that aggravates their condition. But the three grains also contain one of the FODMAP carbohydrates, which can also lead to an alleviation of symptoms. Figuring out which condition is which requires painstakingly-detailed adherence to a diet and support from a dietitian.
Neha Shah, M.P.H., R.D., a certified nutrition support clinician at the Digestive Health Center at Stanford Health Care, encounters both conditions on a regular basis in her practice, and has to work with patients to figure out whether they’re simply gluten sensitive or FODMAP intolerant.
"[FODMAPs] is something I keep in mind when patients are telling me they feel so much better taking the gluten out of the diet,” said Shah in a phone interview with the Huffington Post. "I wonder if they’re reacting to an intolerance of FODMAPs in the wheat, barley and rye versus the gluten itself.” Alternately, said Shah, if patients have eliminated gluten but are still experiencing bad gastrointestinal symptoms, she might explore eliminating even more FODMAP-rich foods from their diet to see if those carbs are the culprits.
Because there’s no official test for FODMAP intolerance, Shah has to use an elimination diet method to determine what patients are allergic to. For her practice, that means cutting out all FODMAP-rich foods for six weeks, and then slowly reintroducing certain foods back in to see which ones provoke a reaction. The re-integration phase is crucial, said Shah, because some people may be allergic to one type of FODMAP but not another, and it’s best to figure out which one it is so that patients can have the widest possible range in diet.
For patients suffering from these bowel conditions, or suspect that they might have FODMAP intolerance, Shah would first start by helping patients eliminate these carbohydrates from their diet: (source: Shah’s charts for Stanford Health Care)
Fructose: high fructose corn syrup, honey and certain fruits like apples, blackberries, boysenberries, dates and figs.
Lactose: in high-lactose dairy products like milk, soft cheese, sour cream, chocolate, buttermilk and custard.
Fructans: wheat, barley, rye, garlic, onions, and inulin (a type of carb found in bananas, leeks, artichokes, and asparagus).
Galactans: in legumes like beans, lentils and soybeans.
Polyols: in stone fruits like avocado, apricots, cherries, nectarines, peaches and plums, as well as artificial sweeteners with isomalt, mannitol, sorbitol and xylitol.
One theory behind FODMAP-caused irritation is that these carbs draw too much water into the intestines, which are then fermented by gut bacteria in the large intestine. The excess water causes diarrhea, while the fermentation causes gas and bloating.
The low-FODMAP diet also seems to have other health benefits too. Since 2005, research has shown that lowering FODMAPs in a diet alleviates irritable bowel syndrome symptoms in patients, and in fact works even better than just a gluten-free diet for IBS patients. IBS causes an estimated 2.4-3.5 million annual doctors visits in the U.S. every year, while inflammatory bowel diseases like ulcerative colitis and Crohn's disease affect an estimated 1-1.3 million Americans.
"There is some research to suggest that those who may have irritable bowel syndrome could have an underlying non-celiac gluten sensitivity or the person could also be intolerant to FODMAPs,” explained Shah. "That’s why a person with irritable bowel syndrome could experience a reduction of symptoms through the low-FODMAP diet.”
But there are still a lot of serious questions about trying to cut FODMAPs from your diet. For instance, even if patients’ gastrointestinal problems go away, it doesn’t necessarily mean that FODMAPs “worked.” Instead, the benefits of the extreme diet have to be weighed against its drawbacks: potential nutritional inadequacy and its yet-unknown effect on other diseases, said Prof. Peter Gibson, one of the pioneering FODMAPs researchers from Monash University in Melbourne, Australia, in a recent study review of FODMAPs.
And it definitely shouldn’t be undertaken by people who are simply trying to lose weight, said Shah, because it has nothing to do with counting calories or cutting “carbs” in the sense that most Americans know it.
“There’s many types of carbohydrates in a [normal] diet, but not all carbohydrates are FODMAPs,” explained Shah. "Even table sugar isn’t a FODMAP, but honey is.” Also, Shah added, the diet is simply too restrictive to sustain over the long term -- unless you saw a compelling change in painful gastrointestinal symptoms, like FODMAP-intolerant people do.
There's still a lot to learn about FODMAPs, said Shah, but the growing evidence is encouraging. She says that it could one day be a more comprehensive diagnosis that explains other dietary intolerances.
“Fructose malabsorption and lactose intolerance have been around for years,” said Shah. "It’s interesting that with this diet, it’s all grouped together now.”