Wheat Belly Total Health: The effortless grain-free health and weight-loss plan. Dr Davis William

Чтение книги онлайн.

СКАЧАТЬ coeliac disease, the destruction of the lining of the small intestine that occurs in people with genetic susceptibility from carrying HLA-DQ2 or HLA-DQ8 genes, coupled with positive tests for transglutaminase or endomysial antibodies and an abnormal biopsy of the small intestine. Coeliac disease affects around 1 per cent of the population and the gliadin, secalin and hordein proteins of wheat, rye and barley are issues only for these people, they argue. Just a few years ago, this represented a major concession from the defenders of grains.

      More recently, this notion has crumbled like stale bread as consensus has grown for the idea that there is another form of intolerance to these same proteins. Labelled non-coeliac gluten sensitivity (NCGS), it is believed to cause many of the same symptoms experienced by coeliac sufferers. Bloating, diarrhoea, abdominal pain, fatigue and headaches are experienced by these people in the absence of the markers for coeliac disease, yet they have symptoms reliably triggered by reexposure to grains. Because of differences in how this condition is defined, anywhere from a few per cent to 30 per cent of the population are estimated to have NCGS.⁸ Some coeliac disease experts have proposed that irritable bowel syndrome, a condition that affects 25 per cent of the population, should be regarded as the same condition as NCGS. People with NCGS have a greater likelihood of antibodies to gliadin; 56 per cent showed such antibodies in one analysis, suggesting that an autoimmune process is at work.⁹ The possibility that NCGS represents reactions to other components of grains, such as WGA or trypsin or amylase inhibitors, has not yet been fully explored. Nonetheless, the expanding world of grain intolerances has kept grain’s defenders busy, and they’ve had to concede that there may indeed be problems with grain consumption in more than the 1 per cent of people with coeliac disease.

      I don’t envy those in the position of having to defend grains. More recently, they have tried to put a positive spin on ‘gluten-free grains’, such as amaranth, rice and millet, hoping to maintain their market presence but deflect growing antigluten criticism. Defend the seeds of grasses as a dietary staple, and it should come as no surprise that you find yourself in an increasingly lonely corner.

      Fortification: Not Good Enough

      It should come as no surprise that, given the gastrointestinal disruption caused by grains, nutrient absorption can be impaired enough to create several common deficiencies. Of course, this is contrary to what we’re told will happen if we consume more ‘healthy whole grains’. Grains like wholemeal bread, stoneground oatmeal and multigrain muffins do indeed have a respectable profile of B vitamins, fibre and phytonutrients. But the nutrients of grains are accompanied by factors that impair the absorption of nutrients, which then cause nutritional deficiencies. This vicious cycle only ends when you remove grains from your diet and seek other sources of nutrients.

      IRON DEFICIENCY began when early humans first consumed the seeds of grasses. Iron deficiency can impair the ability to run, hunt, gather food or tolerate weather extremes, so it has a potential impact on survival. Because of this, it has exerted an evolutionary pressure over the last 10,000 years that led to the appearance of the gene for haemochromatosis, which partially counteracts the iron-impairing effects of grains.¹⁰ All grains contain high quantities of phytates, the component of grains responsible for impaired iron absorption. Ironically, many grain breeders select high-phytate strains of grains because they have improved pest resistance. Whole wheat, corn and millet, for instance, contain 800 milligrams (mg) of phytates per 100 grams (approximately 3½ ounces) of flour. It takes as little as 50 mg of phytates to slash iron absorption by 80 to 90 per cent.¹¹

      Because phytates essentially turn off the human capacity for iron absorption and most of us do not have haemochromatosis, consumption of grains is the most common explanation for iron deficiency anaemia in situations in which blood loss is not the cause.¹² Iron deficiency is a worldwide problem; it’s the most common cause of anaemia. In Egypt, for example, iron deficiency doubled between 2000 and 2005 as grain consumption of baladi bread increased.¹³ The ‘solution’? Fortify the bread with iron. It should come as no surprise that 46 per cent of people with coeliac disease show decreased iron stores (low ferritin levels) and anaemia from iron deficiency, though, because the effect is not mediated by gluten but by phytates, and grain-induced iron deficiency is exceptionally common in those who don’t have coeliac disease, as well.¹⁴ People who have Crohn’s disease, malabsorption and dysbiosis are also more prone to iron deficiency. Grains cause iron-deficiency anaemia with its associated symptoms of fatigue, light-headedness and breathlessness. Grains contain iron, but it is the less well-absorbed ‘non-haem’ form, rather than the more efficiently absorbed ‘haem’ form found in haemoglobin and myoglobin from animal products. Despite the fact that grains contain iron, the net effect of grain consumption is reduced iron status. Iron deficiency is therefore a common health price we pay when we consume the seeds of grasses.

      ZINC DEFICIENCY also develops in populations dependent on grain consumption.¹⁵ Deficiency of zinc was thought to be rare until 1958, when a severe case was diagnosed in an Iranian man who appeared to be around 10 years old at the age of 22. He had an enlarged liver and spleen, heart failure and an appetite for eating dirt. Characteristic of his culture, 50 to 90 per cent of his diet consisted of unleavened tanok bread, along with potatoes, fruit, vegetables and occasional meat. Zinc supplementation corrected his health problems.¹⁶ The component in wheat responsible for the deficiency was not clear, however, until chickens and pigs were diagnosed with zinc deficiency due to the phytate content of wheat fed to them. Zinc deficiency has since proven to be widespread.

      The phytates that block iron absorption are also responsible for blocking zinc absorption. The phytates contained in just 2 ounces of grain flour are sufficient to nearly completely block intestinal zinc absorption.¹⁷ And in the seemingly endless string of breeding blunders, here’s one more: modern breeding efforts have selected plants with higher quantities of phytates because of their pest resistance. The ever-resourceful grain industry has, not unexpectedly, manipulated grain crops to increase zinc content to compensate. (One method includes using fertilizers supplemented with zinc.)

      Zinc deficiency correlates with grain consumption: the more that’s consumed, the more likely zinc deficiency is to develop.¹⁸ This is a nutritional problem of growing worldwide significance, as increasing reliance on grains, especially wheat, corn and rice, has worsened zinc status in an estimated two billion people.¹⁹ Between 35 and 45 per cent of older adults are zinc deficient, and 67 per cent of people with untreated coeliac disease have zinc deficiency.²⁰

      Because zinc is essential for hundreds of different body processes, deficiency can manifest in varied ways. Mild deficiency typically shows as rashes, diarrhoea and hair loss. Vegans, vegetarians and people who limit consumption of animal products are especially prone to zinc deficiency, since plant products contain minimal zinc compared with the higher zinc content of meats, poultry, shellfish and organ meats.²¹ Combine the poor zinc content of plant products with the impaired absorption caused by grain phytates, and it’s not uncommon for vegans and vegetarians to develop difficulties even mounting a normal immune response. Additionally, fertility and reproduction are adversely impacted, children and adolescents can experience impaired growth, and neurological maturation is impaired, among other diverse effects of moderate to severe zinc deficiency. For this reason, the Institute of Medicine has estimated that vegans and vegetarians require 50 per cent more zinc than omnivores.²² Removing grains from the diet improves zinc status, and if lost grain calories are compensated for with an increase in zinc-rich foods, such as meats, there is a net increase in zinc intake and absorption. (Also, see here for more information on how to correct zinc deficiency.)

      VITAMIN B₁₂ DEFICIENCY is also common, affecting 19 per cent of people with coeliac disease and 16.6 per cent of people without coeliac disease.²³ B₁₂ deficiency is another signature deficiency of grain consumption, as several grain components collaborate to impair its absorption. Wheat germ agglutinin (WGA) blocks the intrinsic factor protein produced in the stomach and essential for B₁₂ СКАЧАТЬ