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CHAPTER 3

WHEAT DECONSTRUCTED

WHETHER IT’S A LOAF OF organic high-fibre multigrain bread or a mass-produced biscuit, what exactly are you eating? We all know that the biscuit is just a processed indulgence, but conventional advice tells us that the former is a better health choice, a source of fibre and B vitamins, and rich in ‘complex’ carbohydrates.

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, colour, fibre content, organic or not – it potentially does odd things to humans.

WHEAT: SUPERCARBOHYDRATE

The transformation of the domesticated wild grass of Neolithic times into the modern brownies, cupcakes or Victoria sponge requires some serious sleight of hand. These modern configurations were not possible with the dough of ancient wheat. An attempt to make a modern jam doughnut 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 hybridising wheat for increased yield, plant geneticists have also sought to generate hybrids that have properties best suited to become, for instance, a chocolate cupcake or a seven-tiered wedding cake.

Modern Triticum aestivum wheat flour is, on average, 70 per cent carbohydrate by weight, with protein and indigestible fibre each comprising 10 to 15 per cent. 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 per cent 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, which 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 sweets and fizzy drinks, and increase our consumption of complex carbohydrates.

Of the complex carbohydrate in wheat, 75 per cent is the chain of branching glucose units, amylopectin, and 25 per cent 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 – hence the schoolkid’s chant, ‘Beans, beans, they’re good for your heart, the more you eat ’em, the more you. . . .’ Undigested amylopectin 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, making the sugars unavailable for you to digest.

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. 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, say, kidney beans or crisps. The amylopectin A of wheat products, complex or no, might be regarded as 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. But 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 even simple carbohydrates such as sucrose.

People are usually shocked when I tell them that whole-wheat bread increases blood sugar to a higher level than sucrose.⁴ Aside from some extra fibre, eating two slices of whole-wheat bread is really little different, and often worse, than drinking a can of a sugar-sweetened fizzy drink or eating a sugary chocolate bar.

This information is not new. A 1981 University of Toronto study launched the concept of the glycaemic 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 glycaemic 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 and all – 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-fibre or low-fibre, all generating similarly high blood sugars. Just as ‘boys will be boys’, amylopectin A will be amylopectin A. In healthy, slender volunteers, two medium-sized 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, probably 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 glycaemic properties to extruded pastas.) Pastas are also usually made from Triticum durum rather than aestivum, putting them genetically closer to emmer. But even the favourable 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 periods of 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, comprising as much as 40 to 70 per cent by weight in some purposefully hybridised varieties of wheat.¹⁰

Therefore, wheat products elevate blood sugar levels more than virtually any other carbohydrate, from beans to chocolate 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 the 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 omelette 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 behaviour. 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 am, just two hours after a bowl of wheat cereal or an English muffin breakfast, followed by 11 am pre-lunch cravings, as well as the mental fog, fatigue and shakiness of the hypoglycaemic 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 oestrogen is produced by fat tissue, and the larger the breasts. The bigger your wheat belly, the more inflammatory responses that are triggered: heart disease and cancer.

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 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 coeliac disease, who must eliminate all foods containing gluten from their diets to halt an immune response gone awry, which in coeliac patients essentially destroys the small intestine. As it happens, wheat-free, gluten-free diets are also amylopectin A-free.

However, the weight-loss effects of wheat elimination are not immediately clear from clinical studies. Many coeliac sufferers are diagnosed after years of suffering and begin the diet change in a severely malnourished state due to prolonged diarrhoea and impaired nutrient absorption. Underweight, malnourished coeliac sufferers may actually gain weight with wheat removal thanks to improved digestive function.

But if we look only at overweight people who are not severely malnourished at the time of diagnosis who remove wheat from their diet, it becomes clear that this enables them to lose a substantial amount of weight. A Mayo Clinic/University of Iowa study of 215 obese coeliac patients showed 27.5 pounds of weight loss in the first six months of a wheat-free diet.¹¹ In another study, wheat elimination slashed the number of people classified as obese (body mass index, or BMI, 30 or greater) in half within a year.¹² Oddly, investigators performing these studies usually attribute the weight loss of wheat- and gluten-free diets to lack of food variety. (Food variety, incidentally, can still be quite wide and wonderful after wheat is eliminated, as I will discuss.)

Advice to consume more healthy whole grains therefore causes increased consumption of the amylopectin A form of wheat carbohydrate, a form of carbohydrate that, for all practical purposes, is little different, and in some ways worse, than dipping your spoon into the sugar bowl.

GLUTEN: WE HARDLY KNOW YA!

If you were to add water to wheat flour, knead the mixture into dough, then rinse the glob under running water to wash away starches and fibre, you’d be left with a protein mixture called gluten.

Wheat is the principal source of gluten in the diet, both because wheat products have come to dominate and because most Americans do not make a habit of consuming plentiful quantities of barley, rye, bulgur, kamut or triticale, the other sources of gluten. For all practical purposes, therefore, when I discuss gluten, I am primarily referring to wheat.

While wheat is, by weight, mostly carbohydrate as amylopectin A, gluten protein is what makes wheat ‘wheat’. Gluten is the unique component of wheat that makes dough ‘doughy’: stretchable, rollable, spreadable, twistable, baking gymnastics that cannot be achieved with rice flour, corn flour or any other grain. Gluten allows the pizza-maker to roll and toss dough and mould it into the characteristic flattened shape; it allows the dough to stretch and rise when yeast fermentation causes it to fill with air pockets. The distinctive doughy quality of the simple mix of wheat flour and water, properties food scientists call viscoelasticity and cohesiveness, are due to gluten. While wheat is mostly carbohydrate and only 10 to 15 per cent protein, 80 per cent of that protein is gluten. Wheat without gluten would lose the unique qualities that transform dough into bagels, pizza or focaccia.

Here’s a quick lesson in this thing called gluten (a lesson that you might categorise under ‘Know thine enemy’). Glutens are the storage proteins of the wheat plant, a means of storing carbon and nitrogen for germination of the seed to form new wheat plants. Leavening, the ‘rising’ process created by the marriage of wheat with yeast, does not occur without gluten, and is therefore unique to wheat flour.

The term ‘gluten’ encompasses two primary families of proteins, the gliadins and the glutenins. The gliadins, the protein group that most vigorously triggers the immune response in coeliac disease, has three subtypes: α/β-gliadins, Γ-gliadins and Ω-gliadins. Like amylopectin, glutenins are large repeating structures, or polymers, of more basic structures. The strength of dough is due to the large polymeric glutenins, a genetically programmed characteristic purposefully selected by plant breeders.¹³

Gluten from one wheat strain can be quite different in structure from that of another strain. The gluten proteins produced by einkorn wheat, for example, are distinct from the gluten proteins of emmer, which are, in turn, different from the gluten proteins of Triticum aestivum.^{14, 15} Because fourteen-chromosome einkorn, containing the so-called A genome (set of genes), has the smallest chromosomal set, it codes for the fewest number and variety of glutens. Twenty-eight-chromosome emmer, containing the A genome with the added B genome, codes for a larger variety of gluten. Forty-two-chromosome Triticum aestivum, with the A, B and D genomes, has the greatest gluten variety, even before any human manipulation of its breeding. Hybridisation efforts of the past fifty years have generated numerous additional changes in gluten-coding genes in Triticum aestivum, most of them purposeful modifications of the D genome that confer baking and aesthetic characteristics on flour.¹⁶ Indeed, genes located in the D genome are those most frequently pinpointed as the source of the glutens that trigger coeliac disease.¹⁷

It is therefore the D genome of modern Triticum aestivum that, having been the focus of all manner of genetic shenanigans by plant geneticists, has accumulated substantial change in genetically determined characteristics of gluten proteins. It is also potentially the source for many of the odd health phenomena experienced by consuming humans.

IT’S NOT ALL ABOUT GLUTEN

Gluten isn’t the only potential villain lurking in wheat flour.

Beyond gluten, the other 20 per cent or so of nongluten proteins in wheat include albumins, prolamins and globulins, each of which can also vary from strain to strain. In total, there are more than a thousand other proteins that are meant to serve such functions as protecting the grain from pathogens, providing water resistance and providing reproductive functions. There are agglutinins, peroxidases, α-amylases, serpins and acyl CoA oxidases, not to mention five forms of glycerinaldehyde-3-phosphate dehydrogenases. I shouldn’t neglect to mention β-purothionin, puroindolines a and b, and starch synthases. Wheat ain’t just gluten, any more than Southern cooking is just grits.

As if this protein/enzyme smorgasbord weren’t enough, food manufacturers have also turned to fungal enzymes, such as cellulases, glucoamylases, xylanases and β-xylosidases, to enhance leavening and texture in wheat products. Many bakers also add soya flour to their dough to enhance mixing and whiteness, introducing yet another collection of proteins and enzymes.

In coeliac disease, the one conventionally accepted (though much underdiagnosed) example of wheat-related intestinal illness, gluten protein, specifically α-gliadin, provokes an immune response that inflames the small intestine, causing incapacitating abdominal cramps and diarrhoea. Treatment is simple: complete avoidance of anything containing gluten.

Beyond coeliac disease, though, there are allergic or anaphylactic (a severe reaction resulting in shock) reactions to nongluten proteins, including α-amylases, thioredoxin and glycerinaldehyde-3-phosphate dehydrogenase, along with about a dozen others.¹⁸ Exposure in susceptible individuals triggers asthma, rashes (atopic dermatitis and urticaria), and a curious and dangerous condition called wheat-dependent exercise-induced anaphylaxis (WDEIA), in which rash, asthma or anaphylaxis are provoked during exercise. WDEIA is most commonly associated with wheat (it can also occur with shellfish) and has been attributed to various Ω-gliadins and glutenins.

In short, wheat is not just a complex carbohydrate with gluten and bran. Wheat is a complex collection of biochemically unique compounds that vary widely according to genetic code. Just by looking at a poppy seed muffin, for instance, you would be unable to discern the incredible variety of gliadins, other gluten proteins and nongluten proteins contained within it, many of them unique to the modern dwarf wheat that was your muffin’s source. On taking your first bite, you would enjoy the immediate sweetness of the muffin’s amylopectin A as it sends your blood sugar skyward.

Let’s next explore the incredible wide-ranging health effects of your muffin and other wheat-containing foods.