果糖的麻烦
"Fructose is astrange sugar." That's what I wrote here in2006年7月，我仍然认为这很奇怪。
但是当我写下我的早期文章有关果糖时，我并不了解它的一半。我不知道为什么这么奇怪。在这种情况下，“为什么”至关重要。
Fructose is strange because it is the sweetest sugar and yet has the lowest glycemic index, so it has little immediate effect on our blood glucose levels.
当我们为蔗糖（表糖）分配100的基线值时，那么果糖有一个sweetness factor of 173据加州大学旧金山大学儿科内分泌学教授罗伯特Lustig博士罗伯特Lustig。葡萄糖，我们甚至消化得更快，速度速度快74。Maltose, the highest glycemic sugar, is just 32, and high-fructose corn syrup, a mixture of fructose and glucose, has a sweetness score of 120.
Yet the glycemic index of fructose isonly 19。That's the average of six studies.
我经常想知道果糖是多么甜蜜，血糖如此低。我也想知道为什么这么多人认为高果糖玉米糖浆对我们来说不好。
Joe Anderson has studied the tight relationship between fructose and advanced glycation end products (AGEs). His disturbing report, "AGEs and Aging - Sweet Suicide," helped form my thinking about AGEs, which I wrote about here in可能2006那September 2006那and this可能。虽然接受了他对年龄的担忧，但我仍然质疑他对果糖的关注，因为我不明白。
现在，在本周阅读另外两位专家后，我明白了。第一个是科学作家加里Taubes。他的新书，Good Calories, Bad Calories那is really shaking up my thinking, even though I haven't finished reading it yet, much less having taken the time to digest his extensive and profound critique of the received wisdom that we must minimize the amount of fat that we eat.
Taubes的书是有争议的，并且迫切需要刺激争论多年来。Gretchen Becker，我的好朋友和同伴在这里，回顾了这本书10月28日and10月30日。
吉娜卡塔塔评论了它10月7日New York Times，Taubes回应了10月28日。
所有这些文章都非常值得阅读。此外，Taubes有agreed to answer our questions在HealthCentral.com关于他的新书。
果糖只是Taubes书的一小部分。然而，这是我的重要的醒目者。
“因为果糖几乎寄存在血糖指数中，它似乎是糖尿病患者的理想甜味剂，”Taubes在第197页的讨论开始附近写道附近。“通过在血糖指数的基础上将碳水化合物食品定义为好或坏，糖尿病学家和公共卫生当局有效地误解了果糖对人类健康的影响”（第199页）。
The trouble with fructose is its impact on the liver, which almost exclusively metabolizes it. That's the key point.
它与葡萄糖不同。糖直接进入我们的血液，以便我们的组织和器官可以使用它作为能量，只有30％至40％的通过肝脏。
“饮食中的果糖越多，随后的甘油三酯水平较高，”Taubes写道：第200页。While our health authorities have focused largely on the health risks of high LDL cholesterol levels, Taubes demonstrates that our triglyceride - fat - levels are even more important in terms of our risks for heart attacks.
特别是对糖尿病的人特别麻烦的是，高果糖饮食导致我们分泌更多的胰岛素，这又导致更多的胰岛素抵抗力。那是因为果糖似乎阻断了肝脏中葡萄糖的代谢以及葡萄糖的合成到糖原中，肝脏储存葡萄糖的方式。
Taubes写道，它更糟糕。果糖可能比葡萄糖在我们的身体形式年龄段的葡萄糖中差。
It happened that just as I was reading Taubes, my favorite Certified Diabetes Educator brought to my attention a thought-provoking interview with Dr. Lustig.这次采访那broadcast originally on Australia's ABC Ratio National, confirms the outlines of Taubes's brief against fructose.
"The only organ in your body that can take up fructose is your liver," Dr. Lustig told interviewer Norman Swan. The first thing that eating fructose does is causing an increase in uric acid, Dr. Lustig said. Fructose inhibits nitric oxide, which would otherwise reduce our blood pressure. "So fructose is famous for causing hypertension (high blood pressure)."
"The second is that fructose initiates what's known as de novo lipogenesis, excess fat production".And then the last thing that fructose does in the liver is it initiates an enzyme".What happens is that your insulin receptors in your liver stop working".That means your insulin levels all over your body have to rise."
当我写博士的女儿今天问他的名字of the enzyme that fructose initiates in the liver, he told me that they call it "c-jun N-terminal kinase-1" or just JNK-1 or Junk-1. "It serine phosphorylates a protein in the liver called IRS-1 (insulin receptor substrate-1), thereby rendering it inactive. This induces hepatic insulin resistance."
Dr. Lustig also sent me a PDF of a slides for a talk he recently gave that he called "The trouble with fructose." I swear that this just happens to be the same title I had already decided to use for this article. I have uploaded他的文章到我的网站。
Damning stuff, this. In fact, "we're being poisoned to death," Dr. Ludwig concludes.
当果糖近期麻烦的触发开始于1978年，当时高果糖玉米糖浆进入市场。最常见的形式HFCS-55是55％的果糖和45％的葡萄糖。
HFCS现在是美国最常见的甜味剂。它已经取代蔗糖（表糖），特别是在软饮料中，但也在许多其他食物中。
But HFCS is only the tip of the sugar crystal. Sucrose is half fructose and half glucose.
Sucrose goes by a lot of names on the nutrition labels of the products that we buy in supermarkets and natural food stores. Probably no ingredient is more ubiquitous or goes by so many names as sugar. Sucrose includes white sugar, brown sugar, granulated sugar, turbinado sugar, and most of the sugar in regular and blackstrap molasses and almost all of the sugar in maple syrup. One of the trickiest names is "organic dehydrated cane juice." I'm sure that it fools a lot of people into thinking they aren't getting sugar. Sucanat is another name for dried sugarcane juice. So-called raw sugar includes demerara, muscovado, and turbinado. More than 100 different sucrose substances exist.
Even the天然甜味剂that I have been using occasionally have lots of fructose. From 90 to 97 percent of the sugar in agave nectar is fructose. Up to half of the sugar in some varieties of honey is fructose.
甚至果实，蔬菜和肉类含有一些果糖，两者都直接和这些食物中的一半蔗糖。Among meats，咸牛肉和养猪似乎具有最多的果糖，通过它们增加的蔗糖含量。但果实，蔬菜和肉类并不多的果糖问题，因为我们得到这种方式的总量是最小的。
在1970年到2003年之间的平均消费ructose increased from less than half a pound per year to 56 pounds per year, according to the interview with Dr. Lustig. "We were never designed to take in so much fructose."
Now we know why we need to avoid this added fructose in our diet. But let's not go to extremes. Our bodies were designed to eat the fructose in fruit and vegetables. That naturally-occurring fructose is not the problem. The trouble with fructose is all the fructose and sucrose that we have been adding to our food.
更新：2009年9月16日：一位记者只是通过Lustig博士提出了这个视频。它在YouTube上http://www.youtube.com/watch?v=dbnniua6-om.当你有时间时，值得关注。
