More than 100 million Americans want to avoid gluten, and
they are in good company. Oprah’s 21-day cleansing diet is gluten-free.
Miley Cyrus tweeted: “everyone should try no gluten for a week! The change in
your skin, physical and mental health is amazing! U won’t go back!” In the
best-selling book Grain Brain,
neurologist David Perlmutter, MD, argues that gluten causes dementia and Alzheimer’s.
And, in Wheat Belly (over 1 million
copies sold), cardiologist William Davis, MD includes a section titled, in all-caps,
“BREAD IS MY CRACK!” Dietary demon, indeed.
It would be nice if our current food fears were based on
sound, settled science. But, most beliefs about gluten have little basis in
fact and everything to do with a powerful set of myths — like these three.
Myth: Everyone should
try giving up gluten for a week.
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
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
Myth: Even if you
don’t have celiac disease, there’s a good chance you could have gluten
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
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.”
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