Increasing numbers of people blame foods containing gluten for everything from asthma to dementia, and are now going gluten-free
How many people shun gluten?
Millions. A YouGov poll last year found
that one in ten UK households have at
least one supposedly gluten-intolerant
member, and that 60% of adults have
bought gluten-free products. According
to a US survey by the Consumer Reports
National Research Centre, a third of
Americans are trying to cut it out of their
diets. They have been encouraged in this
by two bestselling science books: Wheat
Belly by cardiologist Dr William Davis;
and Grain Brain by neurologist Dr David
Perlmutter. Both hold gluten responsible
for obesity, inflammation and a host of
other chronic health conditions. The
word has also been spread by a number
of celebrity gluten avoiders – the likes of
Victoria Beckham, Gwyneth Paltrow and
Lady Gaga. Novak Djokovic attributes
his dominance of world tennis in part to going gluten-free.
And are all these millions catered for?
They certainly are. Since the turn of the century, gluten-free has
gone from being an obscure niche to a multimillion-pound
enterprise. Supermarkets now stock a vast range of gluten-free
products, from gluten-free curry and gluten-free chicken nuggets
to gluten-free Easter eggs. In America, you can get gluten-free
vacations, wedding receptions and communion wafers. In 2014
The Wall Street Journal reported a rise in US sales of products
carrying the gluten-free label from $11.5bn in 2010 to $23bn.
But what exactly is gluten?
It’s the spongy complex of proteins, found in wheat, barley and
rye, that gives elasticity to dough and enables it to rise. When flour
is moistened and kneaded into dough, two proteins, gliadin and
glutenin, join together to form an elastic, microscopic latticework
that traps the carbon dioxide produced when yeast ferments,
causing dough to inflate. Baking hardens the gluten, which helps
the finished product keep its shape. Wheat – and thus gluten – is
ubiquitous in the Western diet, and not just in bread, pasta and
cakes; it’s a hidden ingredient in thousands of processed products
such as ice cream, soy sauce and dressings. Yet in evolutionary
terms, wheat is fairly new: it became
a large part of the human diet only
with the advent of agriculture about
10-12,000 years ago.
And why does that matter?
“For the previous 250,000 years, man
had evolved without having this very
strange protein in his gut,” explains
Dr Stefano Guandalini, expert in
digestive disease at the University of
Chicago. Humans simply don’t have
the enzymes to break down gluten, so
some peptides (partially digested bits
of the protein) remain in the intestine.
For most of us, this is insignificant:
they are simply eliminated. But for a
small minority, it causes coeliac
disease: the peptides cross the
intestinal barrier, triggering the
immune system. White blood cells go
on the attack, damaging the intestinal
wall. This results in stomach pain,
diarrhoea, bloating, fatigue, weight
loss and sometimes destruction of the
small intestine. Coeliac disease is a
serious autoimmune condition which
requires the elimination of all wheat, for
life. But many others today believe they
are allergic, or sensitive, to gluten, and
that giving it up improves their health.
Are people right to avoid it?
In most cases, no. Coeliac disease is rare,
affecting about 1% of people in
developed nations. A small number of
others may suffer from allergies or
sensitivities. But the vast majority do not
react badly to gluten – otherwise wheat
would never have become a leading food
source. You could get healthier on a
gluten-free diet because it might increase
your intake of fruit and veg, and reduce
consumption of refined carbohydrates
such as white bread, pizza and puddings.
But such a diet isn’t good for you per se. In fact, if you eat only
gluten-free products, you may be short of vitamins, nutrients and
fibre; they tend to be heavily processed, and can be loaded with
fat and sugar. Tesco’s Free From gluten-free brown bread has
twice as much fat as the normal alternative (and is much dearer).
So why do people like such diets?
Diet fads and phobias have a long history. Many symptoms
blamed on gluten – bloating, fatigue, “brain fog” and lack of
“wellbeing” – have, in the past, been blamed on fat, yeast and
monosodium glutamate. As the New Scientist puts it, we are
prone to “magical thinking” when it comes to diet. And we like
to “copy high-status individuals” like Djokovic. Besides,
psychological factors affect outcomes: the placebo effect and its
opposite, the nocebo effect (where an inert substance has a
damaging effect on a patient’s health) are known to be powerful.
So the benefits of going gluten-free are largely bogus?
The current epidemic of self-diagnosed gluten intolerance is based
on very little evidence. But there are complicating factors. Coeliac
disease is definitely on the rise: US tests show that it has grown
from around 0.2% of the population in the early 1950s to 1%
today. And a high proportion of sufferers are undiagnosed: in the
UK, tests have shown that one in 100
people have the disease, but only one
in 800 is diagnosed (it requires a
blood test and an endoscopy).
Besides, there are also other forms of
wheat allergy and sensitivity.
What are those?
There’s a rare wheat allergy, sometimes
called baker’s asthma, which
causes itching and sneezing. More
controversially, there is “non-coeliac
gluten sensitivity” or NCGS. Sufferers
have coeliac-like symptoms which
resolve themselves when they cut out
gluten. (But it’s not well understood,
very rare, and some scientists
question whether it exists at all.)
Finally, the NHS suggests that those
who suffer from bloating after eating
bread should avoid basic supermarket
loaves, made using fast-acting yeast
and added enzymes. These can cause
gas and indigestion, for reasons that
are nothing to do with gluten.
The rise of “clean eating”
The most recent incarnation of the anti-gluten
philosophy is the trend for “clean eating”. Its standardbearers
in Britain are young, attractive food bloggers
and cookbook authors such as Madeleine Shaw, Ella
Woodward, Tess Ward and the Hemsley sisters. They
encourage people to eat raw, natural foods and to
reduce – or eliminate – ingredients such as sugar,
dairy, wheat and, of course, gluten. Instead of wheat,
they sing the praises of courgetti (courgette spaghetti),
cauliflower rice and other exotic grain alternatives.
While people certainly benefit from eating less refined,
sugary food, questions have been raised about clean
eating. It is based on an irrational fear of gluten (which
Shaw calls “sandpaper for the gut”). Catherine Collins,
principal dietitian at St George’s Hospital, London,
worries that “clean eating plans” are “extremely lowcalorie
and lack important nutrients key for young
women such as iron, calcium and dietary protein”.
There is no such thing as “clean” or “dirty” food,
except in the obvious sense, and such ideas can be
dangerous. Since the 1990s, a condition dubbed
“orthorexia nervosa” has been identified, which
causes sufferers to progressively withdraw food types
– gluten, sugar, dairy – that they see as “wrong”.
