Gluten intolerance

Gluten intolerance – mainly in the head?

Gluten-free food, once seen as fad, has evolved into a multi-billion dollar trend. Why, when scientific reasearch shows only one percent of the US population has celiac disease and only 0.5 percent is allergic to wheat. Like MSG, gluten intolerance looks to be only in the head and, as this article argues, that’s nothing to be ashamed of.

THANKS in part to celebrities such as Oprah Winfrey and Lady Gaga, nearly one-third of all consumers are now interested in gluten-free food, a multibillion dollar industry projected to exceed $10 billion by 2017. (Even children’s play sand now comes with a gluten-free guarantee!)

This is very perplexing, given that only 1 percent of the population has celiac disease and only 0.5 percent is allergic to wheat. What could possibly be causing widespread reports of non-celiac gluten intolerance, commonly blamed for a raft of symptoms including gas, bloating, diarrheoa, constipation, fatigue, goose bumps, dizziness, infertility, migraines, joint inflammation, and even mood disorders?

Scientists are applying themselves to the riddle, with a recent Italian study confirming the existence of gluten intolerance (“non-celiac wheat sensitivity”) as a “distinct clinical condition”.

In the study, one-third of patients who self-identified as gluten intolerant did in fact experience symptom relief after adopting a gluten-free diet. Case closed, right? Pass the gluten-free pasta. Not so fast. An important implication of the study is that two-thirds of people who think they are gluten intolerant really aren’t.

In light of this, it was suggested gently in a Slate report on the Italian study that “patients convinced they have gluten intolerance might do well to also accept that their self-diagnosis may be wrong”.

Predictably, the comment thread exploded with rebuttals: defensive anecdotes, doctrinal pronouncements about the evils of gluten, and accusations of corporate malfeasance, all of which bear a striking resemblance in tone and content to the rhetoric of anti-MSG advocates. For many, the truth of physiological gluten intolerance has now acquired a quasi-religious status.

No one likes to be told they are mistaken about the foundation of their most dearly held beliefs. It offended the faithful when Marx suggested that religions are psychological tools meant to placate the masses. Suggesting that gluten intolerance might have a psychological basis threatens a similarly foundational belief, namely that we are rational beings, competent interpreters of reality immune to mass hysteria and self-deception.

Obviously this is not the case. For one, our memories are notoriously unreliable. You may remember getting headaches from Chinese food when in fact those memories were created when you read about Chinese restaurant syndrome in the news.

The same is true for memories of gluten intolerance. And don’t forget, certainty about your memories is not sufficient evidence of their truth: “Look, I know that for the last 20 years, every time I ate gluten it gave me terrible gas.” Under oath, eyewitnesses constantly forget crucial details and replace them with their own fabrications. They aren’t liars — they’re just human.

One reason for this unreliability is that memory and perception are prone to confirmation bias. Once a bias is in place, we’ll selectively remember — and notice — whatever facts help confirm it.

Food historian, Ian Mosby, has explained the “success” of Chinese restaurant syndrome by connecting it to racialised discourse that drew on a vision of Chinese cooking as bizarre or extreme.

In the case of gluten intolerance, it doesn’t take much to come up with a plausible confirmation bias. Only nine years ago, one in every 11 Americans was on a low-carb diet. In a country terrified of weight gain and recently obsessed with the Atkins diet, gluten makes a great villain.

It’s hard not to notice the theme of weight loss on gluten-free sites. Pasta, bread, cake, cookies, pretzels — they don’t just make you fat, they make you sick! (Added bonus: Diets motivated by a medical condition are far more effective — ask any diabetic.)

Confirmation bias meets physiology in the placebo effect, a well-documented phenomenon in medical treatments ranging from sham drugs to sham acupuncture (where patients respond positively to sham needles) to sham knee surgery. People’s desire to believe in a cure actually affects their symptoms. That’s why placebo-controlled, double-blinded studies are integral to medical research. Without them, we’d be in constant danger of ascribing physiological causality to treatments that are actually psychological.

Needless to say, placebo effects aren’t always beneficial. Strong belief can also render a harmless substance poisonous, which is exactly what happened with MSG. Scientists refer to this as the nocebo effect, and it means that careful studies are necessary to distinguish between poisons and poisonous beliefs…..

Slate: Read the full article