How does food affect mood and mind？ The answer may lie in the chemistry of the brain and nervous system. Molecules① called neurotransmitters are chemical messengers. They carry a nerve impulse across the gap between nerve cells. The release of neurotransmitter② molecules from one neuron and their attachment to receptor sites on another keep a nerve impulse moving.
Nerve impulses carry messages from the environment to the brain for example， the pain you feel when you stub your toe. They also carry messages in the other direction， from the brain to the muscles. That’s why you back away from the obstacle③ that initiated the pain signal and exclaim， “Ouch！”
“Many neurotransmitters are built from the foods we eat，” says neuroscientist Eric Chudler of the University of Washington. Too little or too much of a particular nutrient in the diet can affect their production， Chudler says. For example， tryptophan from foods such as yogurt④， milk， bananas， and eggs is required for the production of the neurotransmitter serotonin. Phenylalanine from beets， almonds， eggs， meat， and grains goes into making the neurotransmitter dopamine.
Dozens of neurotransmitters are known； hundreds may exist. Their effects depend on their amounts and where they work in the brain. The neurotransmitter serotonin， for example， is thought to produce feelings of calmness， relaxation， and contentment. Drugs that prevent its reuptake (into the neuron that released it) are prescribed to treat depression. In at least some healthy， nondepressed people， carbohydrate foods seem to enhance serotonin production and produce similar effects. “It is the balance between different neurotransmitters that helps regulate mood，” Chudler says.
Proper nutrition may also enhance brainpower. Choline⑤ is a substance similar to the B vitamins. It’s found in egg yolks， whole wheat， peanuts， milk， green peas， liver， beans， seafood， and soybeans. The brain uses it to make the neurotransmitter acetylcholine. To test the effects of choline on memory and learning， researchers at the Massachusetts Institute of Technology gave memory tests to college students before increasing the amount of choline in their subjects diets. Later， they retested. On the average， memories were better， and the students learned a list of unrelated words more easily.
① moleculesn. 【化】【物】分子； 微小颗粒
② neurotransmittern. 神经传递素
③ obstaclen. 障碍(物)；妨碍［(+to)］
④ yogurtn. 酸奶；酸乳酪
⑤ cholinen. 【生化】维生素B复合体之一(胆碱)
食物与大脑
食物如何影响情绪和思维？答案可能要到大脑和神经系统的化学结构中去找。被称为神经递质的分子是化学信使。它们把神经冲动带到神经细胞之间的空隙中。神经递质分子从一个神经元释放后，附着到另一个接受点，令神经冲动保持运动的状态。
神经冲动能够把周边环境的信息带到大脑中——例如，当你脚趾被绊了一下时，你会感到疼。它们也能从反方向传递信息，比如说从大脑到肌肉。这就是为什么当障碍物产生疼痛的信号时，你就会躲开障碍物，并且喊：“哎哟！”
华盛顿大学的神经科学家埃里克·查德勒说：“许多神经递质是靠我们所吃的食物形成的。” 查德勒指出过多或过少地通过饮食摄入一种营养素可以影响这些神经递质的形成。例如，来自诸如酸奶、牛奶、香蕉和鸡蛋的色氨酸会产生神经递质的血清素。来自甜菜、杏仁、鸡蛋、肉和谷物中的苯基丙胺酸会形成神经递质的多巴胺。
我们已知的神经递质有几十种，实际存在的可能有几百种。它们产生的效果取决于本身的数量和它们在大脑中工作的位置。例如，神经递质血清素被认为会产生平静、放松和满足的感觉。治疗情绪低落时，大夫就开出一些能够防止它返回（即进入到释放出它的神经元中）的药。至少在一些健康和情绪不低落的人当中，碳水化合物食物似乎能够促进血清素的生成并能产生类似效应。查德勒说：“不同神经递质之间的平衡帮助调节人的情绪。”
恰当的营养能提高人的大脑思考能力。胆碱是一种类似于维生素B的物质。它存在于蛋黄、全麦、花生、牛奶、菜豆、肝、蚕豆、海鲜和黄豆中。大脑利用这种物质生成神经递质的乙酰胆碱。为了检测胆碱对记忆和学习的影响，麻省理工学院的研究者们对大学生进行了记忆测验。随后，他们在被试验者的饮食中增加胆碱的量，重新做了实验。从总体上来看，学生的记忆力有所提高，能够更加容易地学会一系列不相关的单词。