Iron is a micronutrient. Micronutrients are important substances that are found in small amounts in foods.

VOA: special.2011.01.05

The micronutrients, which are available in food but in smaller amounts, are vitamins, minerals, and water.

微量营养素,在膳食中所占比重较小,它们是维生素,矿物质和水

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Now, moving on to the micronutrients, the vitamins, minerals and water; these become pretty interesting.

再说说微量元素,维生素,矿物质和水,这很有趣

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The micronutrients, the vitamins part of the micro nutrients, would fall into several categories.

微量元素,微量元素之一的维生素,各自属于不同的分类

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The macronutrients, protein, carbohydrate and fat; the micronutrients vitamins, minerals and water.

大量营养素,蛋白质,碳水化合物和脂肪,微量营养素,维生素,矿物质和水

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

They appear in food in pretty small amounts which is why they're the micronutrients;, but they're vital for health, so if you're deficient in micronutrients you've got big problems.

它们在食物中所占比重很小,这也是称它们为"微量元素"的原因,但它们对健康的意义却是至关重要的,如果缺乏微量元素的话会很糟糕

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

There are macronutrients and micronutrients and you've heard of both.

可以分为大量营养素和微量营养素两类

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选