同事帶來了布朗尼，女兒為假期的聚會做了曲奇餅，八杆子打不着的親戚也送來了糖果。到處都是糖。糖代表了慶祝，代表了節日，也代表了愛。
但糖也是一種危險。在最近的一項研究中，我們證明了糖分對心血管疾病的發展有推動作用，而且其影響或許比鹽分更大。也有越來越多的證據表明，吃太多糖會引發脂肪肝、高血壓、二型糖尿病、肥胖症和腎病。
然而人們無法抗拒。原因也相當簡單，糖分是有成癮性的。我們所說的「成癮」並不是人們談論美味時的那種意思，而是實實在在的，像毒品一樣的成癮性。而且食品工業正在竭盡所能，試圖把我們勾住。
直到幾百年前，濃縮糖實際上在人類的飲食中還不存在，除非偶然間找到少量野生蜂蜜。糖分在環境中是一種罕見的能量來源，對其產生強烈的渴望，對於人類的生存是有利的。對糖分的渴求會促使我們
尋找甜味的食物，也就是幫助我們堆積脂肪、積蓄能量，以備匱乏時期的那種食物。
今天，添加的糖分隨處可見，在美國買到的包裝食品中，有大約75%含有添加糖分。普通的美國人平均每天消耗的糖分在四分之一磅到半磅（約合110克至220克）之間。如果我們思考一下，今天一聽碳酸飲料里含有的添加糖分，可能高於幾百年前多數人一整年消耗的糖分，就能明白我們周圍的環境發生了多麼巨大的改變。渴求糖分曾經是我們的生存優勢，但現在卻對我們不利。
天然的糖分來源，如完整的水果和蔬菜，糖分濃度通常並不高，因為其中的甜味有水分、纖維和其他成分來緩衝。然而現代工業生產的糖分來源，卻濃重得不自然，很快就能提供巨大的衝擊。就說甜菜這樣的天然完整食品，其水分、纖維、維生素、礦物質，乃至其他所有有益成分都被剝離，用來生產純化的糖。剩下的就只有白色的、純粹的糖晶體。
在這裡與毒品相提並論並不過分。將其他植物，如罌粟和古柯轉變為海洛因和可卡因的提純過程，與上述程序是相似的。純化的糖分也會影響人的身體和大腦。
按照《精神障礙診斷與統計手冊》(Diagnostic and Statistical Manual of Mental Disorders)的定義，列明的11項癥狀中存在至少兩到三種，就構成了物質使用障礙。在動物模型中，糖分至少產生了三種與物質濫用和依賴相吻合的癥狀：渴求感、耐受性、戒斷癥狀。糖分其他與毒品相似的特性還包括（但不限於）交叉敏化、交叉耐受性、交叉依賴性、獎賞效應、阿片效應，以及
大腦中的其他神經化學變化。在動物實驗中，動物對糖的感受就像一種毒品，而且可能會對糖產生依賴。一項
研究顯示，如果提供了選擇，大鼠在實驗室的環境中會選擇糖而不是可卡因，因為前者的獎賞效應更強，即糖帶來的「興奮感」有着更高的愉悅度。
對於人類，這些情況可能也並沒有多大不同。就像鴉片類物質一樣，糖分也會刺激大腦迴路，而研究發現，糖分會
影響人類習慣的形成。糖分產生的渴求感與可卡因和尼古丁等成癮性物質所產生的渴求感可以相提並論。而儘管其他的食品成分也會讓人愉悅，但是在食品當中，糖分可能具有獨一無二的成癮性。例如，對飲用奶昔的人進行的功能性磁共振成像(fMRI)檢測顯示，讓人產生渴望的是糖分，而不是脂肪。食品企業在食品中加入糖分，目的是調整產品成分，使其儘可能地難以抗拒、成癮性儘可能地強。我們怎麼才能戒除這個習慣？一種途徑是通過提高稅收，讓含有添加糖分的食品或飲料更昂貴。另一種途徑則是要求學校、醫院等地，停止提供加糖增甜飲品，或者像監管煙酒一樣監管添加糖分的產品，例如對廣告加以限制，或者加註警示提醒。
但就像我們在兩篇論文——一篇發表在《開放心臟病學》(Open Heart)上，主題是
鹽和糖，另一篇發表在《公共健康營養學》(Public Health Nutrition)上，主題是
糖分和卡路里——里提出的，只是狹隘地關注添加糖分可能會產生始料未及的後果。這樣做可能會促使企業在加工食品中，加入同樣有害，甚至危害更大的其他物質作為替代。
擺脫糖分的更好途徑是，推廣食用未經加工的天然食品。用完整的天然食品替代工業生產的甜食，或許很難讓人接受，然而面對這樣一個利用我們的生物天性讓我們成癮的產業，這對那些渴求糖分攝入的人，或許是最好的方法。
翻譯：王童鶴
OP-ED CONTRIBUTORS
Sugar Season. It’s Everywhere, and Addictive.
By JAMES J. DiNICOLANTONIO and SEAN C. LUCAN December 25, 2014YOUR co-worker brought in brownies, your daughter made cookies for a holiday party and candy is arriving from far-flung relatives. Sugar is everywhere. It is celebration, it is festivity, it is love.
It’s also dangerous. In a recent study, we showed that sugar, perhaps more than salt, contributes to the development of cardiovascular disease. Evidence is growing, too, that eating too much sugar can lead to fatty
liver disease,
hypertension,
Type 2 diabetes,
obesity and kidney disease.
Up until just a few hundred years ago, concentrated sugars were essentially absent from the human diet — besides, perhaps, the fortuitous find of small quantities of wild honey. Sugar would have been a rare source of energy in the environment, and strong cravings for it would have benefited human survival. Sugar cravings would have promptedsearches for sweet foods, the kind that help us layer on fat and store energy for times of scarcity.Yet people can’t resist. And the reason for that is pretty simple. Sugar is addictive. And we don’t mean addictive in that way that people talk about delicious foods. We mean addictive, literally, in the same way as drugs. And the food industry is doing everything it can to keep us hooked.
Today added sugar is everywhere, used in approximately 75 percent of packaged foods purchased in the United States. The average American consumes anywhere from a quarter to a half pound of sugar a day. If you consider that the added sugar in a single can of soda might be more than most people would have consumed in an entire year, just a few hundred years ago, you get a sense of how dramatically our environment has changed. The sweet craving that once offered a survival advantage now works against us.
Whereas natural sugar sources like whole fruits and vegetables are generally not very concentrated because the sweetness is buffered by water,
fiber and other constituents, modern industrial sugar sources are unnaturally potent and quickly provide a big hit. Natural whole foods like beets are stripped of their water, fiber,
vitamins, minerals and all other beneficial components to produce purified sweetness. All that’s left are pure, white, sugary crystals.
A comparison to drugs would not be misplaced here. Similar refinement processes transform other plants like poppies and coca into heroin and cocaine. Refined sugars also affect people’s bodies and brains.
Substance use disorders, defined by the Diagnostic and Statistical Manual of Mental Disorders, exist when at least two to three symptoms from a list of 11 are present. In animal models, sugar produces at least three symptoms consistent with
substance abuseand dependence: cravings, tolerance and withdrawal. Other druglike properties of sugar include (but are not limited to) cross-sensitization, cross-tolerance, cross-dependence, reward, opioid effects and other neurochemical changes in the
brain. In animal studies, animals experience sugar like a drug and can become sugar-addicted. One
study has shown that if given the choice, rats will choose sugar over cocaine in lab settings because the reward is greater; the “high” is more pleasurable.
In humans, the situation may not be very different. Sugar stimulates brain pathways just as an opioid would, and
sugar has been found to be habit-forming in people. Cravings induced by sugar are comparable to those induced by addictive drugs like cocaine and
nicotine. And although other food components may also be pleasurable, sugar may be uniquely addictive in the food world. For instance, functional
M.R.I. tests involving milkshakes demonstrate that it’s the sugar, not the fat, that people crave. Sugar is added to foods by an industry whose goal is to engineer products to be as irresistible and addictive as possible. How can we kick this habit? One route is to make foods and drinks with added sugar more expensive, through higher taxes. Another would be to remove sugar-sweetened beverages from places like schools and hospitals or to regulate sugar-added products just as we do alcohol and tobacco, for instance, by putting restrictions on advertising and by slapping on warning labels.
But as we suggested in two academic papers,
one on salt and sugar in the journal Open Heart and the other on
sugar and calories in Public Health Nutrition, focusing narrowly on added sugar could have unintended consequences. It could prompt the food industry to inject something equally or more harmful into processed foods, as an alternative.
A better approach to sugar rehab is to promote the consumption of whole, natural foods. Substituting whole foods for sweet industrial concoctions may be a hard sell, but in the face of an industry that is exploiting our biological nature to keep us addicted, it may be the best solution for those who need that sugar fix.
James J. DiNicolantonio is a cardiovascular research scientist at Saint Luke’s Mid America Heart Institute.
Sean C. Lucan is an assistant professor at the Albert Einstein College of Medicine.
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