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A group of Nestle SA researchers here are on an unusual mission: They hope to create new foods based on gut instinct.
Not the type of instinct one normally equates with intuitive decision-making, but the sophisticated processes that take place in our digestive tracts to let us know when we're hungry. There, a collection of nerve cells work together and communicate much as the neurons in our brain do. It's essentially an autonomous and self-governing second brain that we all carry in our belly.
The 'gut brain,' formally known as the enteric nervous system, is made up of some 500 million nerve cells, as many as there are in a cat's brain. They help to control muscular contractions in the gut as well as the secretions of glands and cells. And they help balance hunger and satiety, or the sense of being full, communicating those states to the big brain.
Nestle, one of the world's largest food companies, hopes to develop new types of foods that, essentially, seek to trick the gut brain. The foods could make people feel full earlier, or stay full longer, in order to curb the desire to eat more. For example, cooking french fries in oil that gets digested more slowly than regular oil could confer a longer-lasting sense of satiety, researchers speculate.
'This means that people will report a sense of fullness more quickly,' says Heribert Watzke, a senior food scientist at Nestle. 'That tells the big brain to stop eating.'
Nestle says products using its new science could be available within five years. Widely known for its chocolate, the company makes a broad array of foods including cereal, drinks, coffee, frozen meals, bottled water and pet food.
This avenue of food science, which is also being pursued by other food companies, could represent a fresh assault in the fight against flab. One in four Americans is obese, and obesity rates are also rising dramatically in parts of Europe, Asia and the Middle East. Although food companies have long tried to make effective fat-fighting food, their results have been modest.
Nestle and other food giants are now on a push to decipher the language of satiety -- the complex signals our gut brain sends to the big brain -- and use that knowledge to make better satiety-inducing foods, or foods that make you feel full longer. Nerve cells in the gut are located in the tissues lining the esophagus, stomach, small intestine and colon. Like the central nervous system, the gut brain makes use of neurotransmitters such as serotonin and dopamine.
Tracking the movement of food in a person's gastrointestinal tract isn't easy. So at a 'digestion lab' -- part of Nestle's sprawling research and development center here -- scientists use a million-dollar model of the human gut.
The machine is about the size of a large refrigerator. It has several compartments linked by valves, and it is carefully calibrated to the body's temperature. The entire setup is controlled by a computer. The front is glass, allowing observers to watch as food travels through the system.
On a recent day, the 'stomach' section at the top slowly squeezed and churned a salt solution, just like the real thing. The liquefied result then wended its way down the other tubes, representing other sections of the digestive tract. At each stage, tiny valves released the appropriate salt, bile and enzymes, which helped to digest the food.
The body is in a state of continual hunger -- its default position. But several factors work to curtail the hunger instinct, such as the presence of food in the digestive tract, or the flow of nutrients in the blood. When these satiety factors dissipate, the body again demands food.
In the quest to balance hunger and satiety, the gut brain and big brain communicate via neural signals. When food enters the stomach, the stomach stretches, and the gut brain sends a neural message to the big brain. The gut brain also knows when there are nutrients in the gastrointestinal tract, stimulating the release of peptides into the blood and resulting in another message to the brain.
A peptide release is also part of the 'ileal brake' mechanism. The ileum is the lower part of the small intestine. Fat penetrates there when there's too much for the body to process, triggering an 'I'm full' message to the big brain.
Nestle has run some early-stage experiments on foods using its artificial gut model. In a paper published in the journal Food Biophysics last year, Dr. Watzke and colleagues described one such experiment using olive oil. They first measured how long it took the artificial gut to digest olive oil at the natural rate. Then, they added a compound called monoglyceride, which formed a protective coat around the oil molecules, making it harder for the gut's juices to break through and digest the oil.
The Nestle scientists monitored the oil's progress as it gradually went through the system. They found it took eight times longer for the machine to 'digest' the olive oil-monoglyceride combination compared with the olive oil alone. This resulted in more undigested oil reaching the small intestine. In the human body, this could lead to a stronger ileal brake signal of fullness to the big brain.
参考译文：
雀巢公司（Nestle SA）的研究人员正在瑞士沃韦(Vevey)执行一项不寻常的研究任务：根据肠胃本能开发出新型的食品。
这种本能并不是通常相当于直觉决策的那种本能，而是一种在我们的消化道中发生的复杂过程，它让我们知道自己何时饿。在消化道中，一群神经细胞就像大脑中的神经元那样共同协作、相互交流。它基本上可说是我们每个人腹中都有的自主自治的第二个大脑。
“肠脑”的正式名称是肠道神经系统，它由约5亿个神经细胞组成，和猫脑中的神经细胞一样多。它们帮助控制肠道的肌肉收缩、腺体分泌和细胞。它们还帮助平衡饿感与饱腹感，并将这些状态的信息传输给大脑。
雀巢公司是世界上最大的食品公司之一，目前正致力于开发可欺骗肠脑的新型食品。这种食品可以使人们提早感到吃饱，或延长饱腹时间，以抑制进食欲望。例如，研究人员推测，用消化速度慢于普通油的油炸出来的薯条可以产生更长时间的饱腹感。
雀巢公司的高级食品科学家黑里贝特?瓦茨克（Heribert Watzke）说，这意味着人们会更快地感到吃饱了。这会告诉大脑该停止进食了。
雀巢公司称，使用该新科技的产品将于五年内面世。这家因巧克力广为人知的公司还生产许多种食品，包括麦片、饮料、咖啡、冷冻食品、瓶装水和宠物食品。
这种其他食品公司也在开发的食品科技代表着对抗肥胖的战斗中的一股新鲜力量。每四个美国人中就有一个肥胖者，而在欧洲、亚洲和中东的部分国家，肥胖率也在显著上升。尽管食品公司很久以来一直试图生产出能有效对抗肥胖的食品，但收效甚微。
现在，雀巢公司和其他食品业巨头正在努力破译饱腹感语言——肠脑向大脑发出的复杂信号——并利用该知识生产出更好的引发饱腹感或延长饱腹感的食品。消化道中的神经细胞位于食道、胃、小肠和结肠的组织中。和中枢神经系统一样，肠脑利用了羟色胺和多巴胺等神经递质。
跟踪食物在人胃肠道中的运动并不容易。因此，在一间“消化实验室”（雀巢公司庞大的研发中心的一部分）中，科学家们使用了一个价值100万美元的人类消化道模型。
这个机器和一台大冰箱差不多大。它由几个用阀门相连的隔间组成，并细致地调节至人体温度。机器的整体设置由一台电脑控制。机器前方是玻璃屏，让观察者能够看到食物通过该系统的过程。
最近的某一天，机器顶部的“胃”部分缓慢地挤压翻搅着一剂盐溶液，就像真的胃一样。液化产物慢慢下行到代表消化道中其他部分的其他管道里。在每个阶段中，小阀门都会适当地释放出盐、胆汁和酶，帮助消化食物。
身体处于持续饥饿状态之中——这是预设状态。但有几种因素会限制饥饿直觉，例如消化道中有食物存在，或血液中有营养物质流动。当这些导致饱腹感的因素消失后，身体就会再度产生对食物的需求。
在追求饿感和饱腹感的平衡时，肠脑和大脑通过神经信号交流。当食物进入胃时，胃会扩张，肠脑向大脑发出神经信息。肠脑还知道当胃肠道中有营养物质时，主动刺激多肽类物质向血液中的释放，并向大脑发出另一种信息。
释放肽也是“回肠刹车”机制的一部分。回肠是小肠靠下的部分。当这里堆积了太多身体难以处理的食物时，脂肪就会渗入，向大脑发出“我吃饱了”的信息。
雀巢公司用人造消化道模型进行了一些初期食品试验。在去年发表于《食品生物物理学》（Food Biophysics）杂志的一篇论文中，瓦茨克博士及其同事介绍了一项用橄榄油进行的此类实验。他们首先测量了人造消化道在自然速度下消化橄榄油需要多久。然后，他们加入了一种叫单甘油酯的混合物，它在油分子周围形成了一层保护膜，使消化液更难溶解并消化油分子。
雀巢公司的科学家们监测了橄榄油逐渐通过这个系统时的变化过程。他们发现，机器“消化”橄榄油-单甘油酯混合物时花的时间是只加入橄榄油时的八倍。这导致更多未消化的橄榄油到达小肠。在人体中，这可能导致肠脑向大脑发出更强烈的饱腹感“回肠刹车”信号。
