Wheat Belly Cookbook: 150 delicious wheat-free recipes for effortless weight loss and optimum health. Dr Davis William
Читать онлайн книгу.of that day was pretty much untouched by genetic changes, representing only the crude year-over-year efforts by farmers to select for qualities such as hardiness and ability to survive a cold spell. (Since then, kamut has been identified as another 28-chromosome form of wheat and spelt another variation on 42-chromosome wheat.)
It’s dinkel that now dominates the world’s wheat and has been the recipient of all the attentions of geneticists. With 42 chromosomes, dinkel proved to be better suited to the tinkering of geneticists. Now called Triticum aestivum, dinkel wheat is a hardy ‘hexaploid’ version, meaning it comes with three complete pairs of chromosomes (‘hex’ means six), unlike einkorn’s single and emmer’s two paired sets. The greater genetic potential of hexaploid Triticum aestivum means more adaptability and hardiness – and greater potential for genetic changes to be introduced by clever human geneticists.
So dinkel, 42-chromosome hexaploid Triticum aestivum, is the form of wheat that geneticists fiddled with, striving to increase yield-per-acre during the 1960s and 1970s. While the Cold War was smack in the centre of consciousness at that time, the full realization of the power of science to do both good and bad had not yet focused on agriculture. Agricultural science was still young and full of promise, not yet having acquired the tarnished reputation that was to come in the future with herbicides like 2,4-D and 2,4,5-T (the two main components of Agent Orange, used to defoliate the jungles of Vietnam, Laos and Cambodia, resulting in the maiming of hundreds of thousands of natives and American soldiers) and pesticides like DDT that were linked to infertility and birth defects.
During those years, agricultural geneticists worked free from concerns about toxicity and the implications for humans consuming the products of their genetic redesigns. It was still the age of science for the sake of science, with little to no thought devoted to potential consequences for exposed humans.
The techniques used to transform dinkel wheat involved plenty more than just mating two plants. The current strains of wheat – high-yield, semi-dwarf strains – were generated using repetitive hybridization (crossing two strains), wide crossing (crossing two very dissimilar plants, even distantly related wild grasses, to generate unique genetic combinations), repetitive backcrossing (repeatedly crossing to winnow out a specific genetic characteristic), embryo ‘rescue’ (artificially sustaining an embryo of a hybrid that would have died naturally due to mutations), and chemical, gamma ray and x-ray mutagenesis (the purposeful provocation of mutations, followed by cultivation of desired mutants). Most modern strains are the result of many, if not all, of these techniques.
Semi-dwarf wheat started with the 42-chromosome mutant spawn of the Norin 10 dwarf strain from Japan and the Brevor 14 strain from Washington. Progress in developing an especially high-yield strain of wheat was accelerated with the dedication and ingenuity of Dr Nor man Borlaug and colleagues working in Mexico City at the International Maize and Wheat Improvement Center (IMWIC). Thousands of hybridization experiments, crossing strains repeatedly, shuttling seeds back and forth between two very different climates (the high-temperature, low-altitude plains of the Yaquí Valley and the lower-temperature, high-altitude mountains of the Sierra Madre Oriental), helped create a unique, never-before-seen strain of wheat: exceptionally high-yield (tenfold greater yield-per-acre), short (1½ to 2 feet tall), with a thick stem and large seeds.
Mexican farmers quickly recognized the production advantages of this super-yielding strain. It was exported to other countries, including the United States, Canada, India, China and elsewhere. Adopted reluctantly at first in the United States and Canada in the late 1970s because farmers thought it looked peculiar, word spread quickly about this new odd-looking semi-dwarf strain once the remarkable yield-per-acre became evident, and it was embraced widely by the early 1980s. By 1985, virtually all wheat grown in the United States and Canada was the high-yielding semi-dwarf strain. Today, nearly all wheat grown worldwide is the semi-dwarf strain, with only small odd pockets of older strains still under cultivation in southern France, parts of Italy and the Middle East.
This brings us to the present. Today, the wheat products you are sold in the form of whole grain or white bread, bagels, biscuits, cakes, pretzels, pizza and breakfast cereals, as well as the myriad other clever ways food manufacturers have managed to transform this grain, originate with the semi-dwarf brainchild of genetics research. It’s not wild einkorn, it’s not biblical emmer, it’s not spelt or kamut of the Middle Ages, it’s not the dinkel of the 19th century. Modern wheat with its newly introduced genetic changes is uniquely and genetically suited to accommodate our demands for increased yield, more desirable baking characteristics and more pliable dough.
It’s just not perfectly suited for human consumption.
What Changed?
While wheat has been a problematic food for as long as humans have consumed it (with records suggesting coeliac disease, or intestinal damage from wheat gluten, for instance, as long ago as AD 100), modern changes introduced by geneticists made it much worse.
Now, if you take me at my word that wheat has been changed extensively at the hands of geneticists but don’t care to know all the details, then skim the heavy stuff over the next several pages. But if you desire a deeper understanding of what exactly changed, then pour yourself another cup of coffee and read on. Warning: The discussion unavoidably gets a bit complicated for the next several pages. But there are truly important details here for those of you who want to know just what happened.
So what exactly changed?
First, there are obvious outward changes visible to the naked eye. The knee-high semi-dwarf plant has a shorter stalk that diverts less fertilizer and nutrients from the seeds. This change in height is due to changes in Rht (reduced height) genes that code for the protein gibberellin, controlling stalk length (discussed later). The seedhead is larger, with seeds that are also bigger and different in shape. While there is variation among the 25,000 modern strains, semi-dwarf wheat also tends to have reduced protein content and higher carbohydrate content, and it yields different baking and texture characteristics.
The differences in outward appearance are accompanied by internal genetic and biochemical differences.
Gliadin
Gliadin is among the most interesting – and most destructive – of all the many components of modern wheat.
Gliadin is one of the proteins in the gluten family of proteins. Gluten is actually a combination of smaller gliadin proteins and lengthier glutenin molecules. While gluten is often fingered as the source of wheat’s problems, it’s really gliadin that is the culprit behind many health issues.
Gliadin can assume many forms, with more than 200 gene variants coding for as many variations of gliadin protein. The past 50 years of genetics research has introduced extensive changes into gliadin structure, but the full implications of these changes have not been fully mapped out, as they were assumed to be benign. And, after all, this research was performed by agricultural scientists, not doctors or people with insights into human health. Changes in gliadin have therefore been dismissed as harmless, despite the fact that gliadin is capable of increasing intestinal ‘leakiness’ to foreign proteins and triggering cross-reactions with human structures (i.e., triggering an abnormal immune response to similar, though not identical, proteins in the body, a process called molecular mimicry), such as nervous system proteins like synaptin, cells of the intestinal lining (enterocytes) or the ubiquitous calcium-modulating protein calreticulin, potentially triggering inflammatory and immune responses to these proteins.
The changes introduced over the past 50 years in particular have increased the expression of the Glia-α9 amino acid sequence within gliadin that has been most closely linked to triggering coeliac disease. While the genetic sequence coding for Glia-α9 was absent from most strains of wheat from the 19th and early 20th centuries, it is now present in nearly all modern varieties. Glia-α9 is a perfect fit for the transglutaminase enzyme that activates it into the form that strongly binds immune-activating (‘HLA DQ’) molecules lining the intestinal wall, activating the characteristic T-cell immune response that sets coeliac disease in motion. The dramatically increased presence of Glia-α9 likely explains why there has been a fourfold increase in coeliac disease since 1948. (Interestingly, the Glia-α9 sequence, coded for on the sixth chromosome of