Mineral nutrients are fundamentally metals and other inorganic compounds. The life cycle of these mineral nutrients begins in soil, their primary source. Soil provides minerals to plants and through the plants the min...Mineral nutrients are fundamentally metals and other inorganic compounds. The life cycle of these mineral nutrients begins in soil, their primary source. Soil provides minerals to plants and through the plants the minerals go to animals and humans; animal products are also the source of mineral nutrients for humans. Plant foods contain almost all of the mineral nutrients established as essential for human nutrition. They provide much of our skeletal structure, e.g., bones and teeth. They are critical to countless body processes by serving as essential co-factors for a number of enzymes. Humans can not utilize most foods without critical minerals and enzymes responsible for digestion and absorption. Though mineral nutrients are essential nutrients, the body requires them in small, precise amounts. We require them in the form found in crops and they can be classified into three different categories： major, secondary, and micro or trace minerals. This classification is based upon their requirement rather than on their relative importance. Major minerals such as potassium （K） and phosphorus （P） are required in amounts of up to 10 g d-1. The daily requirement of secondary and micro minerals ranges from 400 to 1 500 mg d-1 and 45 ~tg d-1 to 11 mg d-1, respectively. To protect humans from mineral nutrient deficiencies, the key is to consume a variety of foods in modest quantities, such as different whole grains, low fat dairy, and different meats, vegetables and fruits. For insurance purposes, a supplement containing various mineral nutrients can be taken daily.展开更多
Early pottery sherds excavated in northern China date back to more than 11,000 cal a BP,and are presumed to have been used as cooking vessels.There has been,however,no direct evidence to demonstrate this function.Here...Early pottery sherds excavated in northern China date back to more than 11,000 cal a BP,and are presumed to have been used as cooking vessels.There has been,however,no direct evidence to demonstrate this function.Here we report ancient starch grains recovered from carbonized residues adhering to the bases of flatbottomed vessels excavated from the Zhuannian site dating more than 10,000 cal a BP in the North China Plain.This evidence demonstrates that early pottery was being used to cook cereal grains,particularly millets,and acorns.Because millets were in the process of domestication at thistime,we propose that pottery invention in northern China may have been related to early farming activities.展开更多
文摘Mineral nutrients are fundamentally metals and other inorganic compounds. The life cycle of these mineral nutrients begins in soil, their primary source. Soil provides minerals to plants and through the plants the minerals go to animals and humans; animal products are also the source of mineral nutrients for humans. Plant foods contain almost all of the mineral nutrients established as essential for human nutrition. They provide much of our skeletal structure, e.g., bones and teeth. They are critical to countless body processes by serving as essential co-factors for a number of enzymes. Humans can not utilize most foods without critical minerals and enzymes responsible for digestion and absorption. Though mineral nutrients are essential nutrients, the body requires them in small, precise amounts. We require them in the form found in crops and they can be classified into three different categories： major, secondary, and micro or trace minerals. This classification is based upon their requirement rather than on their relative importance. Major minerals such as potassium （K） and phosphorus （P） are required in amounts of up to 10 g d-1. The daily requirement of secondary and micro minerals ranges from 400 to 1 500 mg d-1 and 45 ~tg d-1 to 11 mg d-1, respectively. To protect humans from mineral nutrient deficiencies, the key is to consume a variety of foods in modest quantities, such as different whole grains, low fat dairy, and different meats, vegetables and fruits. For insurance purposes, a supplement containing various mineral nutrients can be taken daily.
文摘维生素A（vitamin A，VA）指可提供视黄醇（retino1）生物活性的两类化合物。其一是视黄醇、其代谢产物及具有相似结构的合成类似物，可称类视黄醇（retinoids）或预先形成的维生素A（preformed vitaminA），主要膳食来源为动物性食物中的视黄醇和视黄酰酯。其二是VA原类胡萝卜素（provitamin A carotenoids），指来自植物性食物、在体内可转化为视黄醇的类胡萝卜素。
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05130603 and XDA05130402)the National Natural Science Foundation of China(40771205 and 41371217)
文摘Early pottery sherds excavated in northern China date back to more than 11,000 cal a BP,and are presumed to have been used as cooking vessels.There has been,however,no direct evidence to demonstrate this function.Here we report ancient starch grains recovered from carbonized residues adhering to the bases of flatbottomed vessels excavated from the Zhuannian site dating more than 10,000 cal a BP in the North China Plain.This evidence demonstrates that early pottery was being used to cook cereal grains,particularly millets,and acorns.Because millets were in the process of domestication at thistime,we propose that pottery invention in northern China may have been related to early farming activities.
