Could Sourdough Bread be the Answer to the Gluten Sensitivity Epidemic?

“I would bet that if you took a dozen people who claimed gluten intolerance and you gave them Richard’s bread, they’d be fine,” says Michael Pollan in the third episode of his new Netflix food documentary, Cooked. The bread he is referring to is a sourdough made the old fashioned way, with hours of fermentation and naturally occurring yeast found in the air by a baker named Richard Bourdon in rural Massachusetts. Bourdon and Pollan go on to explain the importance of proper fermentation of grains to aid in digestion. Pollan says a long fermentation process allows bacteria to fully break down the carbohydrates and gluten in bread, making it easier to digest and releasing the nutrients within it, allowing our bodies to more easily absorb them. Pollan hypothesizes that the speeding up of the bread-making process for mass consumption has so radically altered what we know as bread in the last century that it’s no longer as easily digested.

The idea of sourdough being easier to digest is an intriguing one, and has been making the rounds on blogs devoted to gluten-free eating. In 2011, a small study conducted in Italy tried giving volunteers with celiac disease a small amount of specially prepared sourdough bread. The subjects in the study seemed to react well to the sourdough, which had been fermented until the gluten within it was degraded. The study authors concluded it was not toxic to the celiac disease subjects.

So could bread prepared the slow old fashioned way, the way it was made before added gluten and fast-rising yeast became the norm, be a solution to the gluten intolerance epidemic? Maybe, is the short version of the complicated answer, according to leading celiac experts. For those with true celiac disease, it is too soon to extrapolate the findings of a small study to changes in diet, cautions Joseph Murray, professor of medicine at the Mayo Clinic. “It may provide options for celiacs in the future,” says Murray, adding that he is not hopeful because of the safety margins needed. Just baking sourdough would not be enough. For the bread to be an option, there would have to be a way to work out the baking process so that the gluten is guaranteed to have uniformly degraded to the point where the bread could be tolerated in each batch.

For those with a less severe reaction, with what Pollan calls “gluten intolerance”, which is more commonly known as non-celiac gluten sensitivity, the sourdough process may increase tolerance for consuming the bread, says Alessio Fasano, director of the Center for Celiac Research at Massachusetts General Hospital. The long fermentation process to make sourdough bread the old fashioned way does reduce some of the toxic parts of gluten for those that react to it, says Peter Green, director of the Celiac Disease Center at Columbia University.

While sourdough’s degraded proteins are promising, gluten sensitivity remains mysterious. It’s a relatively new concept, and experts still aren’t sure what causes it. Celiac disease, on the other hand, has been thoroughly studied, says Murray, who refers to it as one of the best understood autoimmune disorders. Gluten sensitivity is another matter. People claiming gluten sensitivity started showing up at celiac centers within the last ten years or so, says Green. When patients first started coming into the clinic, saying they got sick from eating gluten and felt better when they stopped consuming it, with no evidence that they have celiac disease, doctors were skeptical.

Raising awareness of celiac disease has been a blessing and a curse, says Fasano. “We created this monster,” he says, referring to what happened when doctors tried to educate the public about celiac disease. While people now understand the autoimmune disease, and gluten-free products are readily available, the idea that gluten could be responsible for myriad health problems has grown out of control, says Fasano. Celiac disease affects an estimated 1% of the population, though there is concern that the rate is rising. By comparison, an estimated 29% of people in the US are avoiding gluten in their diets. Gluten-free products are a huge business. Everywhere you go, everyone seems to know the name of a wheat protein no one outside the medical and science community could name twenty years ago. Seizing on growing public awareness of celiac disease, books like Wheat Belly: Lose the Wheat, Lose the Weight, and Find Your Path Back to Health, and Grain Brain: The Surprising Truth About Wheat, Carbs, and Sugar – Your Brain’s Silent Killers further popularized the idea that gluten was the culprit in many ills. Popular books like these tend to generalize and skimp on the science, says Murray.

When asked to comment on or review books like Wheat Belly, Murray simply says, “I am a scientist, it is not for me to make literary criticisms on works of fiction.” Public awareness and self help are not the only culprits. Another reason the gluten-free movement has taken off has been the appeal of the idea of a simple fix to so many health issues, says Fasano. The appeal lies in the fact that no diagnosis or pill is needed, he explains. All a person needs to do is go on a diet, without even needing to see a doctor. At the same time, many alternative practitioners have started to prescribe gluten-free diets to their patients for a variety of ills, touting its health benefits, says Fasano, further popularizing the idea that someone could be sensitive to gluten without having celiac disease. The bulk of people on a gluten-free diet don’t have a reason to be on it, says Green, who points out that eating a lot of bread can make a person bloated without it being a “disease state”. While a placebo effect seems to be at work for a lot of people, there are those that really do seem to be reacting to something in wheat without having celiac disease. Some people may experience bloating and flatulence in response to FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) instead of gluten. FODMAPs are a type of carbohydrates that are not well absorbed in the small intestine and are present in bread along with a number of other foods.

For people with irritable bowel syndrome, which has some overlap in gastrointestinal symptoms with celiac disease, FODMAPs can exacerbate symptoms, says Murray. The idea of FODMAPS as the possible culprit came from an Australian research group who accidentally helped popularize the idea of gluten sensitivity, adding fuel to the fire. In 2011, a study of people with irritable bowel syndrome found that subjects felt better when they ate a gluten-free diet. The same research group did a follow-up study, in which they put gluten sensitive subjects on a diet free of both gluten and FODMAPs until they felt better. They then gave some of the subjects gluten and found that they did not react to it, suggesting the problem was FODMAPs and not gluten. But, says Murray, by that time “it was too late to stop this gluten sensitivity train: it had left the station”.

Fermentation during the sourdough process, intriguingly, also reduces FODMAP levels, according to Monash University, where the Australian studies of FODMAPs and gluten sensitivity took place. Breads made in the traditional sourdough process that are made with flours that are low in FODMAPs, like spelt – which does contain gluten – can be tolerated by people who have been shown to have FODMAP sensitivity. FODMAPs may not be the only explanation for the rise in people claiming gluten sensitivity. Wheat itself has not changed in the past 100 years, says Fasano, but there are a lot of vital gluten and enzymes being added to food, so it may be something else in bread or highly processed food that might be causing sensitivity to gluten. There are also theories that changes in our gut microbes could be causing increased reactions to wheat.

Another theory is that people who claim gluten sensitivity are actually reacting to another protein in wheat – Murray points out that wheat is a “complicated food”, made up of many proteins. In the meantime, rates of diagnosed celiac disease are on the rise, according to Murray. People continue to show up at celiac centers saying they are sensitive to gluten, while scientists try to figure out what they could be reacting to and narrow down what has changed in our environment or food. Processed foods are not tested for their impact on human health, so when new additives are introduced, their effect on human health is unknown. The only decisive conclusion available about gluten sensitivity is that more research is needed.

This article was originally published in the US edition of  The Guardian

For more information about celiac disease, visit mayoclinic.org/celiac disease.

Dr. Murray is a gastroenterologist and celiac disease expert at Mayo Clinic.