November 2018 Issue
The Case for Bread
By Carrie Dennett, MPH, RDN, CD
Vol. 20, No. 11, P. 34
Is it the dietary devil it's made out to be?
If bread is the staff of life, why does it elicit so much fear and loathing? Bread's reputation has taken a double hit from the low-carbohydrate and gluten-free trends, blamed for everything from weight gain to celiac disease. Despite its long and revered history, today many people feel virtuous when they avoid the bread basket—or guilty when they eat a sandwich. Have we failed bread … or has modern bread failed us?
Bread's history dates back to the Fertile Crescent, where the world's first urban cultures developed.1 Archeologists have found starch from barley and possibly ancient wheat embedded in a grindstone at a Paleolithic site in Israel dating back approximately 23,000 years, along with evidence of a simple ovenlike hearth, which suggests that the flour made from the grain was baked.2 Both modern and traditional forms of wheat contain essential amino acids, minerals, and vitamins, as well as phytochemicals and fiber. Where modern wheat differs is that it contains fewer mineral micronutrients,3 largely because it's been bred for white flour—and white flour only—says Stephen Jones, PhD, a wheat breeder and director of The Bread Lab at Washington State University's Mount Vernon Northwestern Washington Research & Extension Center.
Jones says wheat is one of the most nutrient-dense foods on the planet, but what we do to wheat turns it into one of the least nutrient-dense foods on the planet. The bran and germ are stripped away, and what's left behind is primarily starch and gluten. "There has been zero effort to increase easy micronutrients like iron, zinc, and selenium," Jones says of modern wheat breeding, adding that how wheat is processed creates more problems. "Industrial plastic-wrapped bread can have over 25 ingredients. Bread needs four."
The Gluten Myth
It's a myth repeated so often that many people take it as truth: Modern bread wheat contains more gluten and is responsible for the increased prevalence of celiac disease and nonceliac wheat sensitivity (NCWS), and heirloom and ancient wheats are the answer.4 Those ancient wheats are einkorn (Triticum monococcum), a diploid wheat (two complete sets of chromosomes) with an AA genome, and emmer (Triticum dicoccoides), a tetraploid wheat with an AABB genome. Emmer evolved from the spontaneous hybridization of einkorn and wild grass. Common wheat, which refers to the hexaploid species with AABBDD genomes, is about 9,000 years old, the result of hybridization between emmer and wild "goat grass" (Triticum tauschii).3 It's the D genomes that contain most of the components that play a role in celiac disease.5,6
Heirloom wheats, also referred to as heritage wheats or landraces, are generally older, open-pollinated, genetically diverse varieties of common wheat, the results of natural evolution and adaptation that were saved by farmers and passed on. Wheat that has adapted to one part of the country likely won't perform well in another—say, the South vs the Great Plains or Arizona vs the Pacific Northwest.7 In addition to differences in their adaptation to different environments, common wheat species also vary in their composition of bioactive components, including gluten.4
Modern wheat debuted in the 1950s with a semidwarf wheat that wouldn't tip over from the weight of the large seed heads fostered by nitrogen-rich synthetic fertilizers.4,8 While wheat grows in 42 states, commodity wheat is grown in wheat belts in the western and plains states on 2,000- to 5,000-acre farms. While this wheat scores high marks for uniformity and high yield in ideal environments, it doesn't prioritize taste or nutrition—nor does it lend itself well to regional farming.8
But what about gluten content? Wheat contains many proteins—the main types being gluten, globulin, and albumin—any of which have the potential to cause an immune reaction. Within the gluten group of proteins are glutenins and gliadins. Gliadins are more likely to be a causal factor in celiac disease and some types of wheat allergy, but modern wheat hasn't been bred for higher gliadin content. It's been bred to encourage high–molecular weight glutenins, proteins that are essential for bread baking quality but carry low risk of causing celiac disease, wheat allergy, or NCWS, says Lisa Kissing Kucek, PhD, a plant breeder at Cornell University in Ithaca, New York.
"The gliadins are the types of proteins that are more likely to be reactive. The glutenins are more important for baking quality," Kucek says, adding that pastry baking calls for flour with more gliadins that have extensibility, or stretch, as opposed to glutenins, which offer the elasticity needed for bread baking. "Modern wheat breeders have been very good at increasing the types of glutenins that make good bread."
As lead author of the 2015 article, "A Grounded Guide to Gluten: How Modern Genotypes and Processing Impact Wheat Sensitivity," Kucek examined the relative immunoreactivity of ancient, heritage, and modern wheats.6 "We looked at hundreds of research papers to see what we could find about what the difference truly is, and we found there is a very tiny difference between modern and heritage wheat for most sensitivities, especially celiac and wheat allergies," Kucek says. "Depending on what type of sensitivity people have, heritage wheats are not going to be the answer most of the time."
Kucek points out that even if a wheat variety is known to be particularly low in immunoreactive proteins, it would be difficult to find that wheat—or bread baked from it—in the store. "Different varieties are grown in different regions, and many flours are blended in the mill. Getting a variety-specific flour is difficult." Plus, a variety that's better for someone with wheat allergy might not be better for someone with celiac disease. "I wish we had more data to say that these are the varieties that are better for this disease or that disease, but it would be a labeling nightmare for the industry."
Rather than looking back, Kucek says the best hope is looking forward—by identifying wheat genotypes that aren't immunoreactive and using them to guide future breeding. "There are efforts, at least with the low-hanging fruit, such as anaphylaxis," Kucek says. "The same thing is being researched for celiac disease, so when breeders develop varieties for different regions, they can screen for these genotypes."
Beyond Wheat Genetics
What Kucek and her coauthors did find was that a larger contributor to immunoreactive compounds is how the wheat is processed—from farm to mill.6 The nutrient composition of wheat, as with other crops, depends on the environment it's planted in and how it's grown. Higher application of nitrogen fertilizers leads to higher protein content overall, but it also specifically boosts gluten—and gliadins.3
Traditional methods such as sprouting and fermenting are largely missing from industrial bread. Sprouting grains, which actually soaks them just short of the sprouting point, activates enzymes in the grain that can break down difficult-to-digest proteins.6 "So does the sourdough fermentation process, which has been used for thousands of years and really changed in the 1920s and '30s," Kucek says. "That said, for people with celiac disease, even fermented and sprouted grains are not going to help them." However, she says these techniques reduce exposure to immunoreactive compounds, which may reduce new cases of celiac disease in genetically predisposed populations.6
Wheats developed before 1870 were grown for stone milling, which crush the germ (the fat- and vitamin B-rich embryo) into the endosperm, distributing both oils and flavor. Although much of the flour is sifted to create white flour from the starchy, protein-rich endosperm, some bran (the outer, fiber-rich skin) and germ remain. "Much less than 1% is stone milled today," Jones says. "It is increasing but slowly. A lot of people are stone milling commodity wheat."
With the Industrial Revolution, stone mills gave way to steel roller mills, which more precisely separate the bran, germ, and endosperm. The removal of the germ, along with the heat generated by the rollers, removes much of wheat's nutrients, one reason why most white roller-milled flour is enriched with iron, folic acid, thiamin, riboflavin, and niacin.9 The remaining micronutrients lost during milling—accounting for 60% to 90% of total nutrients—aren't replaced by fortification. Roller milling meant that the white flour desired by both home and commercial bakers could be produced efficiently. It also paved the way for the industrialization of bread baking. In 1890, 90% of households baked their own bread. By 1930, 90% of households bought industrial white bread.10
How did we get from hand-formed rustic bread made of whole wheat flour, water, salt, and maybe yeast to, as Jones puts it, "Whipped-into-a-frenzy dough that will become a fast-food hamburger bun"? One reason is that industrial baking needs standardized flour that works predictably in large volumes in mechanized assembly lines, which translates to white flour with high protein content and low mineral content. Why the low mineral content? Minerals are found in the bran, and less bran means more endosperm—and more white flour per seed.10
Unfortunately, white flour has fewer enzymes available to help break down the gluten, because most of those enzymes are in the bran.6 But wheat that's bred for white flour and industrial baking isn't optimal for whole wheat bread and natural fermentation because whole wheat dough has to be strong enough to carry the bran and the germ. As a result, many artisan bakers still use mostly white flour.10 Industrial bakers, on the other hand, strengthen whole wheat dough in a way that may have some unintended health effects.
"Whole grain bread started becoming more popular in the 1970s, but people didn't want dense bread; they wanted their fluffy bread," Kucek says. "The thing is with whole grain bread, you have the bran, and that bran can act like little razor blades." This disrupts gluten development and loaf volume. "It's tough to get the fluffy bread that people are used to for their sandwiches. Instead of being careful as with French processes or long fermentation, we started adding gluten after the fact to get the gluten structure that people have come to expect from good bread."
Visit the bread aisle in any grocery store and start picking up loaves of whole grain bread. On the ingredient list you'll see "wheat gluten" or "vital wheat gluten"—gluten separated from wheat flour by washing away the starch granules.5 This is true of both multigrain breads—which include flours from grains that don't contain gluten of their own—and whole wheat breads, even brands perceived to be more healthful. Unless a store stocks artisan breads, odds are good that every loaf will have added gluten.
One problem with adding gluten after the fact is that we don't know the concentration we're getting, Kucek says. Vital gluten intake may have tripled since the late 1970s,5 and consuming isolated gluten could create problems for some individuals. "There are enzymes within the wheat kernel that are important for helping us break down a number of compounds in wheat, including fructans and various gluten compounds," Kucek says.
"When we artificially separate the gluten and add it after the fact, we don't have these enzymes to help us process that. We also don't have that long fermentation to break down the glutens and fructans." Fructans are polysaccharides formed from fructose molecules.
"We can have whole wheat bread without adding wheat gluten if we will accept denser bread," Kucek says. However, there is also a wave of innovation in "postmodern" wheat breeding, selecting for and improving traits that will make it easier and more affordable for bakers to create slow-fermented whole wheat bread that's acceptable to consumers—no added gluten needed.10 Breeders such as Jones aren't using heirlooms wholesale. Instead, they're looking at what favorable traits—flavor, nutrition, high yield, disease, and pest resistance—heirlooms carry that may be adapted to a modern context.
Jones has been breeding wheat since he was an agronomy undergraduate in the late 1970s, growing five acres on a student farm. In the 1990s, after earning his PhD in genetics, he became a chief wheat breeder at Washington State University, unhappily improving commodity wheat that was designed for industrial milling. Today at The Bread Lab, he works with his graduate students to breed wheat and other grains to be used regionally on small farms in the coastal West and other areas of the country. What it means to "improve" wheat has shifted significantly over the years. "Then, it was 'How much white flour can we get per acre?' Yield of white flour is all that mattered," he says. "Now it is high-yielding wheats that are full of iron and zinc and taste great and perform well in whole wheat uses."
Even though Jones often talks about terroir and flavor, two "foodie" words, one of his overarching goals is to help make good bread accessible, affordable, and regional. "Affordable is part of a mature food system," he says. "Twelve-dollar loaves of bread don't help anybody out." That mature system, he says, has no place for ancient and heirloom wheats, because they yield too little. "We have wheat that is nutritious, non-GMO, nonpatented, tastes great, and works well in whole wheat products that will yield 10 times the old wheats. This brings the price point down. We are not interested in boutique wheats," Jones says.
Kucek agrees. "There can be a lot of nostalgic excitement about those old varieties, and they do serve a huge purpose in terms of biodiversity and flavor, but we've moved on from that," she says. "There's a reason we're not growing einkorn as much, and heritage varieties often don't have as much disease resistance."
Bread and Body Weight
If modern wheat itself can't account for the rise in cases of celiac disease and NCWS, what about weight gain? Is bread culpable, despite its role in many traditional diets, including the Mediterranean diet?11,12 In the Spanish arm of the PREDIMED study, researchers tracked bread consumption at baseline and each year for four years in 2,213 participants at high risk of CVD. Their findings suggest that bread consumption isn't associated with clinically relevant increases in weight and abdominal fat, although whole grain bread appeared to have an advantage over white bread for preventing weight gain.13 Researchers from the Spanish SUN study found similar results.14
In Norway, data from the HUNT study suggest that lower intake of bread, especially whole grain bread, was associated with central adiposity.15 A 2012 review published in Nutrition Reviews looked at evidence from 38 epidemiologic studies and found that dietary patterns that include whole grain bread don't contribute to weight gain, and that even white bread at worst shows a "possible relationship" with excess abdominal fat.16
When asked why bread isn't the devil, Jones says simply, "Bread is who we are." So how can dietitians help patients, clients, and consumers make the best possible choice?
"The best way to go about it if you don't have celiac disease but have it in the family or are worried about it is to go for long fermentation, avoid vital wheat gluten, and go for sprouted grains as much as possible," Kucek says. "It is very hard to avoid vital wheat gluten if you are shopping for bread in the grocery store."
— Carrie Dennett, MPH, RDN, CD, is the nutrition columnist for The Seattle Times, owner of Nutrition By Carrie, and author of Healthy for Your Life: A Holistic Guide to Optimal Wellness.
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2. Piperno DR, Weiss E, Holst I, Nadel D. Processing of wild cereal grains in the Upper Palaeolithic revealed by starch grain analysis. Nature. 2004;430(7000):670-673.
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