A couple of decades ago, if you brought up gluten in a conversation with friends, you’d likely have been greeted by blank stares.
Nowadays, everyone’s heard the word “gluten,” and in a similar conversation today, a couple of your friends would probably have strong opinions about it.
Gluten is a type of protein that naturally occurs in wheat, rye, and barley.
People with celiac disease — a serious condition that affects less than 1% of the United States population — have to cut out gluten for life.
Other people have gluten sensitivity or sensitivity to other compounds in wheat, like fructans. These folks might need to reduce their intake of gluten-containing foods.
But all of these individuals are in the minority. So, why are grocery stores packed with gluten-free options?
The rise of gluten-free
In the U.S., the number of people who avoid gluten but don't have celiac disease is slowly creeping up.
For instance, a study using data from the National Health and Nutrition Examination Surveys charts this steady rise. Here are the percentages of people without celiac disease who chose have gluten-free diets:
0.5% in 2009–2010
1.0% in 2011–2012
1.7% in 2013–2014
In other words, the number of people who chose to cut out gluten more than tripled in under a decade.
Similarly, a study involving more than 120,000 participants found that 1.4% of people without celiac disease were following a gluten-free diet in the United Kingdom.
In line with surging popularity, companies that make gluten-free foods have seen a similar growth in their profits.
Today, the gluten-free food market is worth almost $7 billion. Experts expect that to rise to $14 billion in the next 10 years.
A gluten-free diet doesn’t appear to have any health benefits if you don’t have issues with gluten.
According to Dr. Will Bulsiewicz, a board-certified gastroenterologist and ZOE’s U.S. medical director, there’s very little good evidence that gluten is bad for health “when real humans eat real food.” We’ll delve into what that means a little later.
Avoiding gluten can often mean opting for more ultra-processed products that contain high levels of sugar, salt, saturated fats, artificial colors, sweeteners, and other additives, which certainly isn’t better for your health.
Also, having this relatively restricted diet might mean that you miss out on some micronutrients and consume less gut-healthy fiber.
There’s also some evidence that people following a gluten-free diet have higher levels of heavy metals in their bodies.
So, with little evidence that gluten is bad for you and growing evidence that a gluten-free diet might be, how did gluten fall so dramatically from grace?
The birth of a fad
Scientists have known about celiac disease and its links to gluten since the 1950s. And researchers identified gluten sensitivity in some people without celiac disease in the 1970s.
But the gluten-free craze is much more recent.
If you look at Google search data, you can see that there was historically little interest in the search terms “gluten” and “gluten-free.” But around 2010, interest started to increase rapidly.
It’s impossible to pin down the precise moment of genesis, but it seems likely that a few factors converged to produce the perfect storm. We’ll unwind some of these threads here.
The rise of allergies
Only a few decades ago, a peanut allergy was rarely talked about. Today, it affects around 1 in 50 children in the U.S. That’s almost one child in every class.
In the U.K., the prevalence of peanut allergies in 2015 was more than six times higher than it had been in 2000. And in the U.S., the number of people with peanut allergies tripled between 1997 and 2008.
In general — although no one is exactly sure why — allergies appear to be on the rise in the Western world.
The increasing prevalence of allergies doesn’t fully explain why skipping gluten got fashionable. But it might have formed a backdrop in people’s psyche.
You can imagine people thinking, “If so many people have allergies, and I feel tired and bloated more often than I’d like, maybe I have one, too.”
To support this line of thinking, a study published in 2019 — including more than 40,000 people in the U.S. — found that around 1 in 10 people had a food allergy. But around 1 in 5 thought they had a food allergy.
Legitimizing gluten sensitivity
Medical experts argued long and hard about whether some people without celiac disease were sensitive to gluten.
In the 2010s, scientific consensus shifted, and gluten sensitivity became more widely accepted.
In 2011, a group of 15 experts met in London to discuss gluten-related disorders. Following the meeting, a consensus paper appeared in BMC Medicine. Gluten sensitivity was included.
A Second Expert Meeting was held in Germany in 2012. There, experts discussed these conditions further and floated the idea of an official name for gluten sensitivity: non-celiac gluten sensitivity (NCGS).
And in a 2014 paper outlining discussions at the 14th International Celiac Disease Symposium, the authors agreed that NCGS was the term to use.
This scientific recognition wasn’t the start of the craze — the gluten-free food industry made around $2.5 billion in sales in 2010. Still, it lent some legitimacy to avoiding gluten and gave fresh legs to the diet’s proponents.
Around the same time that the medical community recognized NCGS, some scientists were expressing other concerns about gluten. And these concerns surrounded “leaky” guts.
The wall of your intestines isn’t impenetrable. It needs to let nutrients, water, and other compounds into your blood.
Still, it does need to keep some molecules out of circulation.
So-called tight junctions in the membranes that coat the inside of your gut can alter its permeability. They make sure that only the right stuff gets through.
If your gut is too permeable, it lets unwanted compounds reach your blood, sparking inflammation. This is called a leaky gut.
In the early 2000s, scientists identified a compound called zonulin that alters this permeability — more zonulin means more leakiness.
What’s this got to do with gluten? Well, scientists also found that a compound in gluten activates zonulin, thereby increasing permeability and potentially increasing the risk of autoimmune conditions and inflammation.
We spoke to Dr. Will Bulsiewicz about this research. He explains that the conclusions about gluten increasing gut permeability were based on “mechanistic studies where gluten is being administered in isolation in a test tube or to an animal” rather than “studies where humans are eating bread or other gluten-containing foods.” He continued:
"I don't think it's fair to equate gluten in isolated form as the same as eating a slice of bread. Context is important. Food matrix structure and the other components are important."
Indeed, later work showed that although the theory is sound and works in the lab or in animals — in humans, gluten doesn’t affect gut permeability.
Dr. B outlines one study that demonstrates this real-world difference:
“The scientists fed people a low-gluten and high-gluten diet. Real humans eating real food. And when they looked, there was zero evidence in human blood work and testing that the high-gluten diet increased intestinal permeability, zonulin, inflammatory markers, or immune cells.”
Importantly, he continues, “When they looked in the test tube, they did notice some changes suggesting inflammation.” As ever, what happens in the lab doesn’t always match what happens in the body.
Meanwhile, other studies have since shown that eating whole wheat might improve intestinal wall integrity.
So, while those initial studies don’t relate to real-world diets, they may have helped boost an anti-gluten message at a time when its popularity was already on the rise.
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A hotbed of fad diets
Moving on from the impact of scientific research, we need to take a look at our culture and psychology.
It’s no secret that the U.S. and the West generally embrace fad diets. We’re all fans of a quick-fix, no-short-term-suffering-is-too-great-as-long-as-I-get-slimmer mentality.
That people often try multiple fad diets in adulthood is a pretty firm indicator that none of them work. But we keep going. And this isn’t a new phenomenon.
As one example of our long love affair with health fads, in the late 1800s, Horace Fletcher rose to fame with this unusual battle cry: “Nature will castigate those who don't masticate.”
Fletcherism, as it came to be known, claimed that if you chewed every mouthful of food up to 100 times — until it became a liquid — you’d reap health rewards. His book on the technique became a bestseller.
It’s easy to laugh looking back, but when you consider more modern fads, like coffee enemas and perineum sunning, perhaps we haven’t moved on so far.
Over the years, there have also been societal shifts in the nutrients we've demonized. We’ve tried to cut out fats, then lambasted carbs. Where to turn next? Society was looking for a nutritional nemesis, and gluten raised its head above the parapet.
And obesity rates continued to rise in Western populations, so it’s no surprise that people were increasingly eager to find ways to lose weight and feel healthier.
Our readiness to embrace quick-fix fads was just another thread that helped us weave a gluten-free revolution.
The power of popular books
As the gluten-free party began in earnest, a couple of books stirred up public interest further.
One, published in 2013, was called Grain Brain: The Surprising Truth About Wheat, Carbs, and Sugar — Your Brain's Silent Killers. It was written by Dr. David Perlmutter, a neurologist.
As you can glean from its title, this book singles out gluten as a cause of neurological issues. The author outlines 38 conditions or symptoms that we can blame on gluten — from infertility to schizophrenia.
To give you a little extra context, Dr. Perlmutter now advises The Dr. Oz Show. He also receives a mention on the “Promoters of Questionable Methods and Ideas” page of the Quackwatch website.
Grain Brain reached number one on The New York Times bestseller list.
Another book, published in 2016, was Wheat Belly: Lose the Wheat, Lose the Weight, and Find Your Path Back to Health. Its author, cardiologist Dr. William Davis, blames gluten for the rise in obesity.
Although arguments from both books have been dismissed by scientists in medical journals, these journals can't compete with the populist clout of bestsellers.
Where are you getting that info?
Ah, the internet. Depending on where you end up, you can dip your toe into the ever-expanding lake of scientific knowledge or wallow in a swamp of misinformation, disinformation, and scams.
Telling the difference is sometimes tricky because the dirtier end is highly financed and excellent at holding people’s attention with videos, likes, celebrities, and diet “hacks.”
It isn't always easy to tell whether you're seeing a medical doctor speak about solid scientific evidence or a medical doctor peddling shonky weight loss pills.
And when the latter is offering a quick fix, it can seem quite appealing.
Plus, these days, people have a great deal of trust in influencers. We can probably lay some blame at their feet, too.
Indeed, Gwyneth Paltrow claimed in The New York Times that her gluten-free cookbook, published in 2015, started the whole gluten-free craze.
Having read this far, you know that’s not true. But Paltrow’s business model is certainly not reliant on facts.
A number of other celebrities have sung the praises of gluten-free living, including Miley Cyrus, Victoria Beckham, Gerry Halliwell, Kim Kardashian, and Ryan Gosling.
Many sportspeople likewise celebrate a gluten-free lifestyle, including the tennis star Novak Djokovic.
In fact, a survey of almost 1,500 non-celiac sportspeople found that more than 40% had gluten-free diets at least some of the time.
Just as scientific journals can’t compete with bestselling anti-gluten books, the jazzy magnetism of celebrity endorsements is hard to counter.
Whether or not you have a gluten-free diet, you’ll have noticed the increase in gluten-free products. When companies see a trend taking off, they hop on and ride it into the sunset.
As gluten-free foods grew in popularity, so did their marketing budgets. And, whether we like it or not, marketing works.
Manufacturers could label foods as gluten-free and imply that they were better for you. And people are keen to eat foods that are healthy, especially if they’re also tasty.
In reality, many of these foods are ultra-processed and contain lots of sugar, salt, unhealthy fats, and additives.
Not really a fad
The gluten-free diet isn’t really a fad, because this would suggest that it’s short-lived. The diet has now been rumbling along for more than a decade. It’s become part of the fabric of people’s general understanding of food.
Because we’ve heard people badmouth gluten for so long, we tend to believe it.
A survey in 2013 found that 27% of people who chose gluten-free products did so because they thought it would help them lose weight. And 65% thought gluten-free products were better for them.
In seems that gluten isn't even necessarily linked with an allergy or intolerance anymore. It’s just considered a terrible thing that needs to be removed from your diet.
To sum up, multiple threads weaved together to produce a lasting distrust of gluten: a rise in allergies, a new understanding of gluten sensitivity, a long-standing love affair with fad diets, the internet, influencers, and the power of marketing dollars.
Can this poor protein ever shake off its bad name?
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