Departments of Biology and Neuroscience and Behavior, Barnard College, Columbia University, New York, NY, USA.
Handb Exp Pharmacol. 2022;275:321-351. doi: 10.1007/164_2021_451.
One of the distinctive features of the human taste system is that it categorizes food into a few taste qualities - e.g., sweet, salty, sour, bitter, and umami. Here, I examined the functional significance of these taste qualities by asking what they tell us about the nutritional composition and toxicity of foods. I collected published data on the composition of raw and unprocessed foods - i.e., fruits, endosperm tissues, starchy foods, mushrooms, and meats. Sweet taste is thought to help identify foods with a high caloric or micronutrient density. However, the sweetest foods (fruits) had a relatively modest caloric density and low micronutrient density, whereas the blandest foods (endosperm tissues and meats) had a relatively high caloric and high micronutrient density. Salty taste is thought to be a proxy for foods high in sodium. Sodium levels were higher in meats than in most plant materials, but raw meats lack a salient salty taste. Sour taste (a measure of acidity) is thought to signify dangerous or spoiled foods. While this may be the case, it is notable that most ripe fruits are acidic. Umami taste is thought to reflect the protein content of food. I found that free L-glutamate (the prototypical umami tastant) concentration varies independently of protein content in foods. Bitter taste is thought to help identify poisonous foods, but many nutritious plant materials taste bitter. Fat taste is thought to help identify triglyceride-rich foods, but the role of taste versus mouthfeel in the attraction to fatty foods is unresolved. These findings indicate that the taste system provides incomplete or, in some cases, misleading information about the nutritional content and toxicity of foods. This may explain why inputs from the taste system are merged with inputs from the other cephalic senses and intestinal nutrient-sensing systems. By doing so, we create a more complete sensory representation and nutritional evaluation of foods.
人类味觉系统的一个显著特征是，它将食物分为几种味道质量，例如甜、咸、酸、苦和鲜味。在这里，我通过研究这些味道质量告诉我们食物的营养成分和毒性，来研究它们的功能意义。我收集了已发表的关于生的和未加工的食物（即水果、胚乳组织、淀粉类食物、蘑菇和肉类）的组成数据。人们认为甜味有助于识别高热量或高微量营养素密度的食物。然而，最甜的食物（水果）的热量密度相对适中，微量营养素密度低，而最无味的食物（胚乳组织和肉类）的热量和微量营养素密度都相对较高。咸味被认为是高钠食物的代表。肉类中的钠含量高于大多数植物材料，但生肉缺乏明显的咸味。酸味（酸度的衡量标准）被认为表示危险或变质的食物。虽然情况可能如此，但值得注意的是，大多数成熟的水果都是酸性的。鲜味被认为反映了食物中的蛋白质含量。我发现游离 L-谷氨酸（典型的鲜味味觉物质）的浓度与食物中的蛋白质含量独立变化。苦味被认为有助于识别有毒食物，但许多有营养的植物材料味道苦。脂肪味被认为有助于识别富含甘油三酯的食物，但味觉与口感在吸引脂肪食物方面的作用仍未解决。这些发现表明，味觉系统提供的关于食物营养成分和毒性的信息不完整，或者在某些情况下是误导性的。这也许可以解释为什么味觉系统的输入与其他头部感觉和肠道营养感应系统的输入相结合。通过这样做，我们创建了一个更完整的食物感官表示和营养评估。
