Myth: Everyone should try giving up gluten for a week.
Truth: Gastroenterologists are nearly unanimous in their reluctance to recommend “trying out” a gluten-free diet. Stefano Guandalini, MD, medical director of the University of Chicago Celiac Disease Center, said flatly in 2013 that “it is not a healthier diet for those who don’t need it.” Millions who give up bread and hunt for gluten-free toothpaste, he opined, “are following a fad, essentially.”
It’s not just Dr. Guandalini who urges caution when it comes to going gluten-free. Physicians who actually focus on their patients’ wellbeing don’t want them to waste energy and money on a needless elimination diet. In a 2013 state-of-the-field collection of essays, A Clinical Guide to Gluten-Related Disorders, the authors recommend confirming a diagnosis of celiac disease (CD) before “embarking on treatment,” which can be “burdensome to follow and adds significantly to the cost of living.”
These experts are not pawns of Big Food — nor do they run websites that hawk dietary supplements and gluten-free cookbooks. A Clinical Guide was edited by gastroenterologist Alessio Fasano, MD, director of the Mucosal Immunology and Biology Research Center and the Center for Celiac Research and Treatment at Massachusetts General Hospital. He’s among the world’s most influential CD researchers.
Myth: Even if you don’t have celiac disease, there’s a good chance you could have gluten sensitivity.
Truth: Research suggests that almost one in a hundred Americans — 3 million — may be affected by celiac disease. Of these, only 17% are diagnosed, which means 2.5 million Americans might be living with undiagnosed CD. For these people, gluten and related proteins cause a dangerous autoimmune reaction. The symptoms range widely, from acute gastrointestinal pain and skin rashes to increased risk for certain cancers, infertility, and neurological disorders.
Then, there are the people who don’t have CD but may experience symptoms (usually joint pain, fatigue, “foggy mind,” or numbness of their extremities) after ingesting gluten. This is referred to as non-celiac gluten sensitivity (NCGS), a condition that remains a matter of considerable debate. One study about NCGS, conducted at Australia’s Monash University, received lots of attention. It was a double-blind, randomized, placebo-controlled study — the “gold standard” of dietary studies — and it found that “irritable bowel–like symptoms of gluten sensitivity” were more frequent in people treated with gluten (68%) than in the subjects who did not have gluten (40%). Many people took this to confirm that just because you don’t have CD, it doesn’t mean your “gluten sensitivity” is all in your head. But, the same researchers at Monash conducted another study that came to a remarkably different conclusion. Using an even more rigorous trial design, they found there were “no effects of gluten in patients with self-reported non-celiac gluten sensitivity.” The authors hypothesized that gluten sensitivity was actually being confused with sensitivity to special carbohydrates known as FODMAPs (short for fermentable oligo-, di-, mono-saccharides and polyols). While FODMAPs are found in grains such as wheat, rye, and barley, they also occur in a wide variety of “gluten-free” or “healthy” foods like broccoli, garlic, onions, apples, and avocados. In other words: Those who think they have NCGS may be reacting to what’s inside their sandwiches as much as the bread itself. Although more research needs to be done, the results of this second study suggest that some people who go gluten-free might be better off on a low-FODMAP diet.
Myth: Look at the science. One study found that a gluten-free diet reduces the pain of endometriosis. Another showed a link between eating gluten and depression. This research proves that gluten is “bad.”
Truth: The problem here is that running a few studies doesn’t “prove” or “conclusively show” anything. Good nutrition science depends on the long, slow accumulation of data over many, many studies — something scientists themselves know very well. They are (or should be) highly skeptical of single studies. Enthusiastic gurus who speak confidently on the dangers of grains are exaggerating the field — and exaggeration in science is nothing less than a lie.
Paradoxically, our faith in science makes it difficult to identify and dismiss lies about nutrition. Food seems so simple to study. If we can put a man on the moon, transplant a heart, and manipulate DNA, then surely we can unpack the relationship between eating vegetables and living longer. There’s no obvious difficulty in figuring out if wine decreases the risk of heart disease, or if red meat increases the risk of colon cancer. Just look at people who drink wine or eat red meat, and then compare them to those who don’t. Easy, right?
In fact, there is probably no branch of medicine more difficult or complicated than nutrition science, a complexity that plays out in the endless controversies about what — and how much — we should eat. High-quality studies of dietary practices are incredibly hard to design. How do you make a placebo piece of steak for your control group? Studies on the effect of diet and lifestyle in large populations are no less difficult. They depend on recollection and self-reporting, notoriously unreliable data. And, even if that data were accurate — well, just tweak an equation, exclude a set of data points, isolate a different factor, and suddenly vegetarianism goes from increasing longevity to decreasing bone density. This is why nutrition scientists who study “ideal diets” have made surprisingly little progress over the years.