什麼是麩質?
What is gluten?

麩質 (Gluten) 是一種可在小麥（wheat）、大麥（barley）及黑麥（rye）找到的蛋白質，中文譯名包括小麥麩質、麵筋、麥膠蛋白、小麥蛋白等。中文名稱的「高筋粉」和「低筋粉」也是由此而來。
Gluten-free flour are made from plants that are naturally gluten-free. Since gluten is the skeleton of the dough, without this means you have to make adjustments in the portion of other ingredients. A usual way is to add starch, such as tapioca starch, to enhance the binding power of the dough and improve the skeleton. 

Image source: firsteat.in

麵筋是麵粉的柔軟骨架
Gluten is the soft skeleton of flour ​

小麥主要成分是澱粉質，其次是蛋白質，約佔12至14%，這些蛋白質也是做麵包或蛋糕的「筋」。做麵包要用高筋麵粉，其蛋白質含量可達16至18%，搓麵糰時開始有彈性、拉扯時呈一絲絲的狀態，即麵粉開始「起筋」。麵筋的作用，是為麵糰搭建立體層架，包裹酵母在發酵時產生的二氧化碳，讓麵包在烘焙時膨脹，形成鬆軟口感。所以，麥麩不僅是蛋白質的來源，在保持食物外觀與口感上也有作用。
Wheat mainly consists of starch, second comes the protein of around 12-14%. In bread flour the protein can be as high as 16-18%. The protein, i.e. gluten, helps form the “soft skeleton” of the dough. Under fermentation, yeasts produce carbon dioxide and such skeleton allows the gas to expand and get trapped under high temperature in the oven, resulting in a fluffy and light texture in breads. Not only proteins, gluten gives elasticity to baked goods and the ‘chewy' texture of many breads and products.

Photo source: Leite's Culinaria

我們吃的「小麥」不是小麥
The "wheat" we eat today is no longer wheat

市場上有抗殺蟲劑的小麥，那不是經過基因改造，而是通過一種稱為「化學誘變」的過程進行改變。(1)
這個過程涉及將種子暴露於超有毒化學物質以及輻射以引發突變。這一切都是不受政府管制的，不需要在產品上標記，也無需進行安全測試，因為它仍被歸納為「傳統育種方法」或「雜交」而不是基因改造，唯是後者受到更嚴格的監管。
William Davis博士撰寫的「小麥完全真相」一書中提到：
「現代小麥是40年遺傳學研究的產物，志在提高每畝產量。結果是一個基因獨特的植物，高18-24英寸，一個“半侏儒＂，而不是4 1/2英尺高的「琥珀色穀物」。傳統小麥早已不存在，這種產品從1985年左右開始就消失了。今天，幾乎所有用小麥粉製成的產品，無論是有機的，發芽的，雜糧等，都來源於這種高產﹑半侏儒的遺傳學研究。」(2)
There IS wheat on the market that is herbicide-resistant. It is not genetically modified but altered through a process called chemical mutagenesis. (1)
It involves exposing the seed to a super-poisonous chemical as well as radiation, with the intent of introducing a mutation. This is all unregulated and does not need labeling because it still counts as “traditional breeding methods” or “hybridization” rather than genetic modification, which is more highly regulated. No safety testing is required.
In the book “Wheat Belly” written by Dr. William Davis, he mentioned:
“Modern wheat is the product of 40 years of genetics research, intensive efforts aimed at increasing yield-per-acre. The result: a genetically unique plant that stands 18-24 inches tall, a “semi-dwarf” strain, not the 4 1/2-foot tall “amber waves of grain” we all remember. Traditional wheat is long gone, a product that has not been on store shelves since around 1985. Today, virtually all products made with wheat flour, regardless of whether it is organic, sprouted, multigrain, etc., originates from this high-yield, semi-dwarf creation of genetics research.” (2)

Image source: yoga-anatomy.com

「為了說明這件事，讓我們假裝你和我是邪惡的科學家。我們希望看到當我們與猩猩交配人類主體時會發生什麼。後代的結果是什麼？我不確定，因為可能有各種各樣的變化，讓我們稱之為實驗生物 “Homo orangatanus”。接下來，我們將這個生物與其他類似的生物繁殖幾代。然後，我們將子宮內的胚胎暴露於γ射線照射，高劑量X射線和誘變突變的化學物質（此稱為「化學誘變」），以產生各種突變，如身材矮小，體毛少，攻擊性更強，行為更快增長等。
經過幾十年此類的活動，我們得出什麼？我不確定，但它肯定不再是人類，也不再是猩猩，甚至遠離 “Homo orangatanus”。這是完全不同的東西，不像任何自然會發生的東西。如果沒有各種人工方法來維持生命，它甚至可能無法生存。」(3)
​“To illustrate just how far this thing has come, let’s pretend you and I are evil scientists. (Sorry, but this is kind of gross; read on at your own risk.) We want to see what happens when we mate a human subject with an orangutan. What offspring results? I’m not sure, since an infinite variety of variations are possible, but let’s call our experimental creature Homo orangatanus. Next, we cross this creature with other similar creatures over several generations. We then expose the embryos while in utero to gamma irradiation, high-dose x-ray, and mutation-inducing chemicals (“chemical mutagenesis”) to generate various mutations, such as short stature, less body hair, more aggressive behavior, more rapid growth, etc.
After several decades of such activities, what do we have? I’m not sure, but it certainly is no longer human, it’s no longer orangutan, even far removed from Homo orangatanus. It is something entirely different, unlike anything that occurs naturally. It may not even be able to survive without all manner of artificial methods to sustain its life.” (3)

這就是小麥發生的事情：重複的選擇性雜交（穿過不同的品種產生新的特徵，例如在後代中產生5％的蛋白質，在任一親本中都不存在），回交（重複雜交以獲得特定的性狀，例如身材矮小），與非小麥植物雜交（引入完全獨特的基因）和誘導突變（化學﹑γ-和X-射線誘變，即使用厭惡的刺激誘導突變，然後繁殖後代，例如BASF的Clearfield小麥是通過將種子和胚胎暴露於對人類具有高度毒性的工業化學品疊氮化鈉來生產的）。
This is what happened with wheat: Repeated selective hybridizations (crossing different strains to generate new characteristics; 5% of proteins generated in the offspring, for instance, are not present in either parent), backcrosses (repeated crossing to winnow out a specific trait, e.g., short stature), and hybridized with non-wheat plants (to introduce entirely unique genes), and induced mutations (chemical-, gamma-, and x-ray mutagenesis, i.e., the use of obnoxious stimuli to induce mutations that can then be propagated in offspring, e.g. BASF’s Clearfield wheat is produced by exposing the seeds and embryos to the industrial chemical, sodium azide, that is highly toxic to humans.). 

你今天吃的「小麥」甚至不應該被稱為小麥。
The “wheat” you eat today shouldn’t even be called wheat anymore.

麩質相關的疾病
Gluten-related sickness

麩質是小麥的主要蛋白質。此蛋白質有四種類型：球蛋白(Globulins)，白蛋白(Albumins)，麥谷蛋白 (Glutenins) 和麥醇溶蛋白 (Gliadins)。有害的蛋白質主要是麥醇溶蛋白和麥谷蛋白 (4)。2012年16位全球領先的麩質研究人員在一份共識聲明中總結了當前關於麩質相關疾病的科學觀點 (5)。麩質的反應形式主要分為三種：
1）過敏性（小麥過敏）與IgE抗體相關
2）自身免疫系統（乳糜瀉，麵筋共濟失調，皮膚炎）
3）可能的免疫介導（麩質敏感）
Gluten is the main protein complex of wheat. There are four types of proteins: Globulins, Albumins, Glutenins and Gliadins. The toxic proteins of gluten are mainly gliadins and glutenins (4).
In 2012 sixteen of the world’s leading gluten researchers summarized the present scientific view on gluten related disorders in a consensus statement (5). Three main forms of gluten reaction are recognized:
1) Allergic (wheat allergy) – IgE antibodies
2) Autoimmune (celiac disease, gluten ataxia, dermatitis)
3) Possibly immune mediated (gluten sensitivity)

麩質敏感
Gluten sensitivity

「小麥過敏」能夠透過血液檢測 IgE抗體。很多沒有檢測到麩質抗體的人在吃麩質後仍然會有嚴重的症狀，如腹痛，濕疹或皮疹，頭痛，疲勞，腹瀉，抑鬱症，關節痛等。這情況稱為「麩質敏感」。
"Wheat allergy" can be diagnosed by blood test and detection of IgE antibodies. Many people who show no positive antibody tests for gluten can still have severe symptoms after eating gluten, such as abdominal pain, eczema or rash, headache, “foggy mind”, fatigue, diarrgea, depression, joint pain etc. This condition is called "gluten sensitivity".

美國神經學家David Perlmutter在他的書“Gain Brain”中寫道，在他的經歷中，他那些被診斷患有多發性硬化症的病人在許多情況下都患有乳糜瀉，而無麩質飲食可能改善他們的症狀 (6)。他提出麩質敏感可能損害認知功能，導致癡呆。
A study by the American neurologist, David Perlmutter, stated in his book “Gain Brain” that in his experience his patients improved their symptoms with a gluten free diet (6). He suggested that gluten sensitivity can impair cognitive functions and cause dementia. A lethal disease triggered by gluten causing inflammation in the white matter of the brain is gluten encephalopathy.

腹脹是從麩質中獲得反應的症狀之一。
Bloating is one of the symptoms of getting a reaction from gluten. 
（Image source: Instagram @balanceforyou)

麩質敏感，乳糜瀉與自閉症
Gluten sensitivity and celiac disease in autism

乳糜瀉是遺傳易感個體中小腸的慢性免疫介導的炎症，具有如腹瀉，便秘，腹痛，腹脹，鈣，鐵等營養素缺乏等症狀。
麩質會引起腸道內的炎症反應，導致腸粘膜變平。麥醇溶蛋白使粘膜釋放一種稱為「連蛋白」(zonulin) 的物質，使粘膜變得滲漏，令未被消化的麩質和其它有害物質可直接穿過腸壁進入血流，粘膜也不能正常吸收營養。這被稱為「腸漏症」(5)。
Celiac disease is a chronic immune mediated inflammation of the small intestine in genetically susceptible individuals, with symptoms such as diarrhoea, constipation, abdominal pain, abdominal bloating, deficiency of nutrients such as calcium, iron, etc. Gluten cause an inflammatory reaction in the intestine membrane causing flattening of the intestinal mucosa. Gliadin causes the mucosa to release a substance called zonulin which cause the mucosa to become leaky so that undigested gluten and other harmful substance can cross the intestinal wall into the blood stream. The mucosa also becomes unable to perform a normal uptake of nutrients. This is being known as the “leaky gut” (5).

Image source: thepediablog.com

三十位自閉症兒童至少有一名可能患有乳糜瀉 (7)。 大多數自閉症兒童對麩質敏感。 由於麩質敏感與身體抗體無關，不能在血液中被檢測到，診斷這疾病的唯一方法是透過在飲食中消除麩質並觀察其健康狀況。
在兩項自閉症飲食干預的對照隨機臨床研究指出，兒童服用無麩質和無酪蛋白飲食後有顯著的改善，相反對照組則沒有任何變化 (8)；孩子的注意力提高，變得不那麼咄咄逼人，不那麼多動，開始聊得更多。 這飲食上的改變幫助了三分之二的兒童 (9)。在患有過度活躍症和自閉症的兒童中，無麩質飲食可能幫助改善他們行為和神經症狀。
At least one child with autism out of 30 could suffer from celiac disease (7). The majority of children with autism are gluten sensitive. Since gluten sensitivity is not related to antibodies and there are no biomarkers in blood, the only way to diagnose this condition is to study how health and well being improve by eliminating gluten.
Two controlled randomized clinical studies of diet intervention in autism have been published. Children in the diet group who put on a gluten and casein free diet showed significant improvement while there was no change in the control group (8). Children’s attention improved and they became less aggressive, less hyperactive and started to talk more. The diet helps two thirds of the children (9). In children with ADHD or ADD a gluten free diet often improves behavioural symptoms, and in autism behavioural and neurological symptoms usually improve.

無麩質飲食的誤解
Myth about gluten-free diet

1) 無麩質飲食可以減肥
Gluten-free diet can help you slim down

近年隨著無麩質食品逐漸興起，引身「無麩質飲食法」，聽起來像很健康，但分分鐘無麩質食物的卡路里比正常飲食更為高！全因無麩質產品為做出如用小麥製般的鬆軟質感，很多生產商會添加額外的糖和油！只看是否無麩質而不看營養標籤有機會令你減肥變增肥！選購時謹記得要看成分和營養標籤，看清楚糖和油含量，才好購買！

按此看低脂曲奇 Click to see low-calorie cookies

2) 無麩質食品較為健康?
Gluten-free food is healthier?

正如以上提及，生產商很多時加額外的糖和油，就算是無糖或低糖，也要留意營養標籤是否有化學代糖，例如：
E950 乙醯磺胺酸鉀 AcesulfameK (ACE-K)，
E954 糖精Saccharin，
E951/962 阿斯巴甜 Aspartame；
或含有化學添加劑，如乳化劑，膨脹劑，穩定劑：
E927a Azodicarbonamide (麵粉改良劑)，
E310/311/312 Propyl Gallate (穩定劑)。 

然而，不少天然無麩質穀物營養價值高，未必比麩質穀物差！如：
藜麥(Quinoa)：受聯合國糧食及農業組織認定為唯一的完美營養食品，含人體所需的全部9種氨基酸，更含豐富的礦物質。
畫眉草/苔麩 (Teff)：埃塞俄比亞的特產，是世界上最細小的殼物（100粒苔麩才等於1粒小麥！）不只低脂肪還富鐵質！
蕎麥 (Buckwheat)：含礦物質銅，有益心臟健康；錳，有利新陳代謝及發育生長；更有芸香醇/ 蘆丁(Rutin)，可幫助防止血栓形成)
另外，無麩質穀物多為非基因改造，適合喜歡天然自然的你！

要看 7+1 營養標籤啊!
Remember to read the nutritional labels!

3) 無麩質食品一定難食?
Gluten-free food tastes gross?

無麩質食品通常使用其他穀物取代小麥，例如：米﹑糙米﹑糯米﹑蕎麥﹑高梁﹑苔麩等。材料非傳統，但不一定代表難食呢！ 無麩質也可同樣造出蛋糕，曲奇和麵包，無敏都可以好好食！

由國際無敏食品協會主辦的無敏烘焙課程
Allergen-free baking course organized by Freefrom Foods International Association

加上無敏市場愈來愈流行和成熟，無麩質食品已進步了許多。日常生活其實很多美食都是無麩質（特別是中式食品），如湯圓﹑馬蹄糕﹑芋頭糕﹑白糖糕等。 不妨多認識嘗試不同的產品，找出心儀無麩質食品！

認識無麩質麵粉 About gluten-free flour

Reference:
​(1) Katie Kimball, Wheat is NOT Genetically Modified…so why so Many Sensitivities?, kitchenstewardship.com
(2) Dr. William Davis, Wheat: Up close and personal, 25/9/2011
(3) Dr. William Davis, Wheat is NOT "genetically-modified", 14/2/2012
(4) Harald Blomberg, Gluten-related disorders in children and adults, 2014
(5) Sapone A. et al. Spectrum of gluten-relate disorder: consensus on a new nomenclature and classification, BMC Medicine 2012 10:13
(6) ​David Perlmutter, Grain Brain: The Surprising Truth about Wheat, Carbs, and Sugar--Your Brain's Silent Killers, 2013
(7) Wakefield A, Waging war on the autistic child, 2012.
(8) Knivsberg A M, Reichelt KL, Hojen T el al.: A randomised, controlled study of dietary intervention in autistic syndromes. Nutritional Neuroscience 2002: 13:87-100
(9) Whiteley P, Haracopos D, Knivsberg AM et al. “The ScanBrit randomized, controlled, single-blind study of a gluten-and casein-free dietary intervention of children with autism spectrum disorders.” Nutritional neuroscience 2010; 13;87-100