DON’T BE A PEST
If you’re a farmer, encountering a pest feasting on your wheat field is a feared development. And there are many of them, from fungal rusts to wheat curl mites to sawflies. Farmers and agricultural geneticists therefore work to develop wheat strains that have better pest-resistant properties.
Wheat comes with its own built-in pest-resistant protein called wheat germ agglutinin. The greater the wheat germ agglutinin content in a stalk of wheat, the greater its ability to fend off a pest trying to feast on it. After all, the plant cannot run away, or claw or bite the invader. When an insect eats a part of the wheat plant, wheat germ agglutinin attacks its gastrointestinal tract, either killing the creature or impairing its ability to generate offspring.
Modern wheat strains have therefore been chosen for greater wheat germ agglutinin content.15 This peculiar protein is completely indigestible to humans: What goes in the mouth as a component of pretzels or crackers comes out unchanged in a bowel movement. As we shall discuss in the next chapter, in its course from mouth to toilet, however, wheat germ agglutinin acts as an exceptionally potent bowel toxin, essentially ripping apart the intestinal lining when given to experimental animals in pure form, less dramatically but still quite damagingly so when ingested as crust on pepperoni pizza. The small quantity that enters the bloodstream in humans amplifies inflammation and is hormonally disruptive. More on this to come.
The enrichment of wheat germ agglutinin is yet another illustration that what’s good for the farmer and crop is not necessarily good for the consumer who feasts on onion bagels and penne pasta.
In the future, the science of genetic modification (GM) has the potential to change wheat even further. No longer do scientists need to breed strains or expose seeds or embryos to toxic chemicals or gamma rays, cross their fingers, and hope for just the right mix of chromosomal change. Instead, single genes can be purposefully inserted or removed and strains bred for disease resistance, pesticide resistance, cold or drought tolerance, or any number of other genetically determined characteristics. In particular, new strains can be genetically tailored to be compatible with specific fertilizers or pesticides. This is a financially rewarding process for Big Agribusiness and seed and chemical producers such as Cargill, Monsanto, BASF, and ADM, since specific strains of seeds can be patent protected and thereby command a premium and boost sales of the compatible chemical treatments. While no strain of GM wheat is yet on store shelves, nearly all corn is genetically modified and, to a lesser degree, rice, cousins of our favorite grass-to-bash, wheat.
Genetic modification is built on the premise that a single gene can be inserted in just the right place without disrupting the genetic expression of other characteristics. While the concept seems sound, it doesn’t always work out that cleanly. In the first decade of genetic modification, no animal or safety testing was required for genetically modified plants, since the practice was considered no different from the assumed-to-be-benign practice of hybridizing two strains of grasses. Public pressure has, more recently, caused regulatory agencies, such as the food-regulating branch of the FDA, to require testing prior to a genetically modified product’s release into the market. Critics of genetic modification, however, have cited studies that identify potential problems with genetically modified crops. Test animals fed glyphosate-tolerant soybeans show alterations in liver, pancreatic, intestinal, and testicular tissue compared to animals fed conventional soybeans. The difference is believed to be due to unexpected DNA rearrangement near the gene insertion site, yielding altered proteins in food with potential toxic effects, as well as the inclusion of herbicides tied to the GM crop such as glyphosate or the Bt toxin pesticide coded into the GM crop, now ingested by humans as hamburger buns and gluten-free cookies.16
It took the introduction of gene modification to finally bring the notion of safety testing for genetically altered plants to light. Public outcry prompted the international agricultural community to develop guidelines, such as the 2003 Codex Alimentarius, a joint effort by the Food and Agricultural Organization of the United Nations and the World Health Organization, to decide what new genetically modified crops should be subjected to safety testing, what kinds of tests should be conducted, and what parameters should be measured.
But no such outcry was raised years earlier as farmers and geneticists carried out tens of thousands of hybridization and chemical mutagenesis experiments. There is no question that unexpected genetic rearrangements that might generate some desirable property, such as greater drought resistance or better dough properties, can be accompanied by changes in proteins that are not evident to the eye, nose, or tongue, but little effort has focused on these side phenomena. Hybridization and other efforts continue, breeding new “synthetic” wheat. While they fall short of the precision of gene modification techniques, they still possess the potential to inadvertently “turn on” or “turn off” genes unrelated to the intended effect, generating unique characteristics, not all of which are presently identifiable.17
Thus, alterations of wheat that could potentially result in undesirable effects on humans are not due to gene insertion or deletion, but are due to manipulations that predate genetic modification. As a result, over the past sixty years, thousands of new wheat strains have made it to the commercial food supply and supermarket shelves without a single effort at safety testing. This is a development with such enormous implications for human health that I will repeat it: Modern wheat, despite all the genetic alterations to modify thousands of its genetically determined characteristics, made its way to the worldwide human food supply with nary a question surrounding its suitability for human consumption.
Because hybridization experiments did not require the documentation of animal or human testing, pinpointing where, when, and how the precise hybrids that might have amplified the ill effects of wheat is an impossible task.
The incremental genetic variations introduced with each effort at “improving” wheat strains can make a world of difference. Take human males and females. While men and women are, at their genetic core, largely the same, the differences clearly make for interesting conversation, not to mention romantic moments in dark corners. The crucial differences between human men and women, a set of differences that originate with just a single chromosome, the diminutive male Y chromosome and its few genes, set the stage for thousands of years of human life and death, Shakespearean drama, and the chasm separating Homer from Marge Simpson.
And so it goes with this human-engineered grass we still call “wheat.” Genetic differences generated via thousands of human-engineered manipulations make for substantial variation in composition, appearance, and qualities important not just to chefs and food processors, but also to human health.
CHAPTER 3
WHEAT DECONSTRUCTED
WHETHER IT’S A loaf of organic high-fiber multi-grain bread or a Twinkie, what exactly are you eating? We all know that the Twinkie is just a processed indulgence, but conventional advice tells us that the former is a better health choice, a source of fiber and B vitamins, rich in “complex” carbohydrates, and your ticket to a life of slenderness and freedom from diabetes, heart disease, and colon cancer.
Ah, but there’s always another layer to the story. Let’s peer inside the contents of this grain and try to understand why—regardless of shape, color, fiber content, organic or not—it potentially does peculiar and harmful things to humans.
WHEAT: SUPERCARBOHYDRATE
The transformation of domesticated wild grass of Neolithic times into modern Cinnabon rolls, French crullers, or Dunkin’ Donuts requires some serious sleight of hand. These modern configurations were not possible with the dough of ancient wheat.
An attempt to make a modern jelly donut with einkorn wheat, for example, would yield a crumbly mess that would not hold its filling, and it would taste, feel, and look like, well, a crumbly mess. In addition to breeding wheat for increased yield, geneticist
s have also sought to generate strains with properties best suited to become, for instance, a chocolate sour cream cupcake or a seven-tiered wedding cake.
Modern Triticum aestivum wheat flour is, on average, 70 percent carbohydrate by weight, with protein and indigestible fiber each comprising 10 to 15 percent. The small remaining weight of Triticum wheat flour is fat, mostly phospholipids and polyunsaturated fatty acids.1 (Interestingly, ancient wheat has higher protein content. Emmer wheat, for instance, contains 28 percent or more protein.)2
Wheat starches are the complex carbohydrates that are the darlings of dietitians. “Complex” means that the carbohydrates in wheat are composed of polymers (repeating chains) of the simple sugar, glucose, unlike simple carbohydrates such as sucrose that are one- or two-unit sugar structures. (Sucrose is a two-sugar molecule, glucose + fructose.) Conventional wisdom, such as that from your dietitian or the USDA, says we should all reduce our consumption of simple carbohydrates in the form of candy and soft drinks, and increase consumption of complex carbohydrates.
Of the complex carbohydrate in wheat, 75 percent is the chain of branching glucose units, amylopectin, and 25 percent is the linear chain of glucose units, amylose. In the human gastrointestinal tract, both amylopectin and amylose are digested by the salivary and stomach enzyme amylase. Amylopectin is efficiently digested by amylase to glucose, while amylose is much less efficiently digested, some of it making its way to the colon undigested. Thus, the complex carbohydrate amylopectin is rapidly converted to glucose and absorbed into the bloodstream and, because it is most efficiently digested, is mainly responsible for wheat’s blood-sugar-increasing effect.
Other carbohydrate foods also contain amylopectin, but not the same kind of amylopectin as wheat. The branching structure of amylopectin varies depending on its source.3 Amylopectin from legumes, so-called amylopectin C, is the least digestible. Undigested amylopectin C makes its way to the colon, whereupon the symbiotic bacteria happily dwelling there feast on the undigested starches and generate gases such as nitrogen and hydrogen—hence the schoolkids’ chant, “Beans, beans, they’re good for your heart, the more you eat, the more you…”—making the sugars unavailable for you to digest but forcing you to excuse yourself from a business meeting.
Amylopectin B is the form found in bananas and potatoes and, while more digestible than bean amylopectin C, still resists digestion to some degree. The most digestible form of amylopectin, amylopectin A, is the form found in wheat and its grain brethren. Because it is the most digestible, it is the form that most enthusiastically increases blood sugar. This explains why, gram for gram, wheat increases blood sugar to a greater degree than kidney beans or potato chips. The amylopectin A of wheat products, complex or no, is a supercarbohydrate, a form of highly digestible carbohydrate that is more efficiently converted to blood sugar than nearly all other carbohydrate foods, simple or complex.
This means that not all complex carbohydrates are created equal, with amylopectin A–containing wheat increasing blood sugar more than other complex carbohydrates. The uniquely digestible amylopectin A of wheat also means that the complex carbohydrate of wheat products, on a gram-for-gram basis, are no better, and are often worse, than simple carbohydrates such as sucrose.
People are often shocked when I tell them that whole wheat bread increases blood sugar to a higher level than sucrose.4 Aside from some extra fiber, eating two slices of whole wheat bread is really little different, actually worse, than drinking a can of sugar-sweetened soda or eating a sugary candy bar.
This information is not new. A 1981 University of Toronto study launched the concept of glycemic index, i.e., the comparative blood sugar effects of carbohydrates: the higher the blood sugar after consuming a specific food compared to glucose, the higher the glycemic index (GI). The original study showed that the GI of white bread was 69, while the GI of whole grain bread was 72 and Shredded Wheat cereal was 67, while that of sucrose (table sugar) was 59.5 Yes, the GI of whole grain bread is higher than that of sucrose. Incidentally, the GI of a Mars bar—nougat, chocolate, sugar, caramel—is 68. That’s better than whole grain bread. The GI of a Snickers bar is 41—far better than whole grain bread.
In fact, the degree of processing, from a blood sugar standpoint, makes little difference: Wheat is wheat, with various forms of processing or lack of processing, simple or complex, high-fiber or low-fiber, organic or non-organic, all generating similarly high blood sugars. Just as “boys will be boys,” amylopectin A will be amylopectin A. In healthy, slender volunteers, two medium slices of whole wheat bread increase blood sugar by 30 mg/dl (from 93 to 123 mg/dl), no different from white bread.6 In people with diabetes, both white and whole grain bread increase blood sugar 70 to 120 mg/dl over starting levels.7
One consistent observation, also made in the original University of Toronto study as well as in subsequent efforts, is that pasta has a lower two-hour GI, with whole wheat spaghetti showing a GI of 42 compared to white flour spaghetti’s GI of 50. Pasta stands apart from other wheat products, likely due, in part, to the compression of the wheat flour that occurs during the extruding process, slowing digestion by amylase. (Rolled fresh pasta, such as fettuccine, has similar glycemic properties to extruded pastas.) Pastas are also usually made from Triticum durum rather than aestivum, putting them genetically closer to emmer. But even the favorable GI rating of pasta is misleading, since it is only a two-hour observation and pasta has the curious ability to generate high blood sugars for four to six hours after consumption, sending blood sugars up by 100 mg/dl for sustained periods in people with diabetes.8, 9
These irksome facts have not been lost on agricultural and food scientists, who have been trying, via genetic manipulation, to increase the content of so-called resistant starch (starch that does not get fully digested) and reduce the amount of amylopectin. Amylose is the most common resistant starch, increased to as much as 40 to 70 percent by weight in some purposefully hybridized varieties of wheat.10
Wheat products therefore elevate blood sugar levels more than virtually any other carbohydrate, from beans to candy bars. This has important implications for body weight, since glucose is unavoidably accompanied by insulin, the hormone that allows entry of glucose into the cells of the body, converting glucose to fat. The higher the blood glucose after consumption of food, the greater the insulin level, the more fat is deposited. This is why, say, eating a three-egg omelet that triggers no increase in glucose does not add to body fat, while two slices of whole wheat bread increases blood glucose to high levels, triggering insulin and growth of fat, particularly abdominal or deep visceral fat.
There’s even more to wheat’s curious glucose behavior. The amylopectin A–induced surge in glucose and insulin following wheat consumption is a 120-minute-long phenomenon that produces the “high” at the glucose peak, followed by the “low” of the inevitable glucose drop. The surge and drop creates a two-hour roller coaster ride of satiety and hunger that repeats itself throughout the day. The glucose “low” is responsible for stomach growling at 9:00 a.m. that necessitates a snack, just two hours after a bowl of wheat cereal or an English muffin breakfast, followed by 11:00 a.m. prelunch cravings, as well as the mental fog, fatigue, and shakiness of the hypoglycemic glucose nadir.
Trigger high blood sugars repeatedly and/or over sustained periods, and more fat accumulation results. The consequences of glucose-insulin-fat deposition are especially visible in the abdomen—resulting in, yes, wheat belly. The bigger your wheat belly, the poorer your response to insulin, since the deep visceral fat of the wheat belly is associated with poor responsiveness, or “resistance,” to insulin, demanding higher and higher insulin levels, a situation that cultivates diabetes. Moreover, the bigger the wheat belly in males, the more testosterone is converted to estrogen by fat tissue, and the larger the breasts. In susceptible females, testosterone is increased, accompanied by facial hair and infertility. The bigger your wheat belly, the more inflammatory
responses that are triggered: heart disease, cancer, and dementia.
Because of wheat’s morphine-like effect (discussed in the next chapter) and the glucose-insulin cycle that wheat amylopectin A generates, wheat is, in effect, an appetite stimulant. Accordingly, people who eliminate wheat from their diet consume far fewer calories, something I will discuss later in the book.
If glucose-insulin-fat provocation from wheat consumption is a major phenomenon underlying weight gain, then elimination of wheat from the diet should reverse the phenomenon. And that is exactly what happens.
For years, wheat-related weight loss has been observed in patients with celiac disease, who must eliminate all foods containing gluten from their diets to halt an immune response gone awry, which in celiac patients essentially destroys the small intestine. As it happens, wheat-free, gluten-free diets are also amylopectin A–free, especially if other grains are eliminated.
However, the weight loss effects of wheat elimination are not immediately clear from clinical studies. Many celiac sufferers are diagnosed after years of suffering and begin the diet change in a severely malnourished state due to prolonged diarrhea and impaired nutrient absorption. Underweight, malnourished celiac sufferers may actually gain weight with wheat removal thanks to improved digestive function.
Wheat Belly Success Story: Kathleen
“Just came back from my annual physical, where I managed to shock the bejeezus out of my doctor, which is not an easy thing to do.
“She looked at my vitals and last year’s report, looked at me, and said in complete surprise, ‘What have you been doing?! What happened to last year’s issues?’ Meaning dangerously low blood pressure, heart palpitations, GERD (gastroesophageal reflux disease), Barrett’s esophagitis (a nasty little swallowing disorder), leg edema, unstoppable weight gain/BMI in the obese range, chronic fatigue and brain fog, and zero libido to be the frosting on that little cake of unpleasantness.
Wheat Belly (Revised and Expanded Edition) Page 5
