Chapter Thirteen – Kiwifruit and Mineral Nutrition第十三章猕猴桃与矿物质营养

Chapter Thirteen - Kiwifruit and Mineral Nutrition第十三章猕猴桃与矿物质营养

Abstract
Dietary minerals are essential nutrients that drive key cellular and physiological functions. Each mineral is absorbed in the gut via unique, complex pathways that can involve a cascade of receptors and binding proteins. Foods can both provide dietary minerals and contain components that impact the bioavailability of minerals in the digestive system. Kiwifruit exceeds most other fruits in its content of key micronutrients including potassium, phosphorus, magnesium, calcium, iron, and folate. It also contains exceedingly high levels of ascorbic acid, which increases the bioavailability of nonheme iron and can impact on calcium absorption. Recent research in cells, animals, and humans has demonstrated that kiwifruit, particularly the gold variety, can increase the uptake and retention of the essential dietary minerals iron, calcium, phosphorus, and magnesium.

▲A kiwi orchard with abundant fruits

摘要
膳食矿物质是驱动关键细胞和生理功能的必需营养素。每种矿物质都通过独特而复杂的途径被肠道吸收，这些途径可能涉及一系列受体和结合蛋白。食物既能提供膳食矿物质，又含有影响消化系统矿物质生物利用度的成分。猕猴桃在钾、磷、镁、钙、铁和叶酸等关键微量营养素的含量上超过了大多数其他水果。它还含有极高水平的抗坏血酸，这增加了非血红素铁的生物利用度，并可能影响钙的吸收。最近对细胞、动物和人类的研究表明，猕猴桃，特别是黄金品种，可以增加对必需膳食矿物质铁、钙、磷和镁的吸收和保留。

▲Kiwi Pollination

Introduction
Dietary minerals are inorganic elements that are required in small quantities but are essential for health. They have a number of functions within the human body. Some, such as copper and magnesium, stabilize the structure of proteins and DNA. Other minerals, such as calcium and phosphorus, are themselves important structural components of bone. A number of minerals are enzyme cofactors or are involved in redox reactions and electrical gradients (Fleet, Replogle, & Salt, 2011). Key dietary minerals include iron, magnesium, calcium, copper, and potassium. Even people who consume high-energy Western diets may be deficient in minerals such as iron and calcium, while illness can contribute to deficiencies in potassium and magnesium. New research continues to refine and evolve our understanding of the mechanisms through which dietary minerals are independently or synergistically absorbed and utilized in the body.

▲Red kiwifruit

Mineral uptake is dependent on the level in the diet and the needs of the body but is also modulated by other factors. Dietary minerals must be bioavailable: that is, they must be present in a form in which the digestive system is able to remove them from food and absorb them into the bloodstream for use in the body. Antinutritional factors can lower the bioavailability of a mineral by chelating it and making it insoluble; conversely, some food components can enhance bioavailability by making favorable changes to the gut microenvironment (Hunt et al., 1995, Hurrell, 2003, Lopez et al., 2003, Record et al., 1996, Song et al., 2012). Similarly, processing, refinement, and cooking or storage procedures used on a food can affect its mineral content and bioavailability (Kimura and Itokawa, 1990, Reddy and Love, 1999). In addition, interactions occur between minerals in the body so that a deficiency or excess of one mineral can affect the status of another mineral (Lonnerdal, 2010, Pepin and Shields, 2012).
Kiwifruit both contain minerals and impact the absorption of several dietary minerals. These include iron, magnesium, calcium, copper, and potassium, which are discussed individually in more detail below.

▲佳沛在国内销售的进口红心猕猴桃

介绍
膳食矿物质是少量必需的无机元素，但对健康至关重要。它们在人体内具有多种功能。一些，如铜和镁，可以稳定蛋白质和DNA的结构。其他矿物质，如钙和磷，本身就是骨骼的重要结构成分。许多矿物质是酶辅因子或参与氧化还原反应和电梯度（Fleet、Replogle和Salt，2011）。关键的膳食矿物质包括铁、镁、钙、铜和钾。即使是食用高能量西方饮食的人也可能缺乏铁和钙等矿物质，而疾病也可能导致钾和镁的缺乏。新的研究继续完善和发展我们对膳食矿物质在体内独立或协同吸收和利用的机制的理解。
矿物质吸收取决于饮食水平和身体需求，但也受到其他因素的调节。膳食矿物质必须具有生物可利用性：也就是说，它们必须以消化系统能够将其从食物中清除并吸收到血液中以供体内使用的形式存在。抗营养因子可以通过螯合矿物质并使其不溶来降低矿物质的生物利用度；相反，一些食物成分可以通过对肠道微环境进行有利的改变来提高生物利用度（Hunt等人，1995，Hurrell，2003，Lopez等人，2003，Record等人，1996，Song等人，2012）。同样，食品上使用的加工、精炼、烹饪或储存程序会影响其矿物质含量和生物利用度（Kimura和Itokawa，1990，Reddy和Love，1999）。此外，体内矿物质之间会发生相互作用，因此一种矿物质的缺乏或过量都会影响另一种矿物的状态（Lonnerdal，2010，Pepin和Shields，2012）。
猕猴桃既含有矿物质，又影响几种膳食矿物质的吸收。这些包括铁、镁、钙、铜和钾，下文将分别详细讨论。

▲KiwiPollen

Essential Dietary Minerals
The human body contains 2–4 g of iron (Bothwell, Charlton, Cook, & Finch, 1979). The majority of this iron is found in hemoglobin, the erythrocyte protein responsible for transporting oxygen from the lungs to the body's tissues. Much of the remaining iron in the body is found in myoglobin, a protein important for the storage of oxygen in muscle tissue. Iron acts as a transport medium for electrons in cells and is an important component of many enzymes, playing a role in oxidative metabolism and Mineral Absorption in the Digestive System

必需膳食矿物质
人体含有2-4g铁（Bothwell，Charlton，Cook，&Finch，1979）。大部分铁存在于血红蛋白中，血红蛋白是负责将氧气从肺部输送到身体组织的红细胞蛋白。体内剩余的大部分铁存在于肌红蛋白中，肌红蛋白是一种对肌肉组织中氧气储存很重要的蛋白质。铁在细胞中充当电子的运输介质，是许多酶的重要组成部分，在氧化代谢和消化系统中的矿物质吸收

▲新建的黄心猕猴桃果园

The pH of the digestive system differs in each compartment, and the mechanisms and locations of a mineral's absorption are partly determined by the pH at which the mineral is soluble. Some minerals, such as magnesium and calcium, are soluble within a wide pH range and thus remain as free ions through the entire digestive system. Others, such as iron and copper, are soluble only under acidic conditions and form insoluble precipitates in nonacidic compartments of the digestive system (Powell,

消化系统的pH值在每个隔室中都不同，矿物质吸收的机制和位置部分取决于矿物质可溶的pH值。一些矿物质，如镁和钙，在很宽的pH范围内是可溶的，因此在整个消化系统中保持游离离子状态。其他物质，如铁和铜，仅在酸性条件下可溶，并在消化系统的非酸性室中形成不溶性沉淀物（Powell，

▲准备开始加工猕猴桃花粉的鲜花

Iron
Dietary iron is found in two well-characterized forms: heme and nonheme iron. Heme iron is found in red meat, chicken, and fish. Heme iron is well absorbed (15–35% absorbed from meals), with dietary factors and an individual's iron status having only a small effect on absorption (Gibson, Donovan, & Heath, 1997). Most dietary iron is in the form of nonheme iron, which is present in meats, eggs, cereals, legumes, pulses, fruit, and vegetables. However, the absorption of nonheme iron is poor
铁
膳食铁有两种特征明显的形式：血红素铁和非血红素铁。血红素铁存在于红肉、鸡肉和鱼中。血红素铁吸收良好（从膳食中吸收15-35%），饮食因素和个人的铁状态对吸收的影响很小（Gibson，Donovan和Heath，1997）。大多数膳食铁以非血红素铁的形式存在，存在于肉类、蛋类、谷物、豆类、水果和蔬菜中。然而，非血红素铁的吸收较差

▲where are zespri kiwi grown

Minerals in Kiwifruit
Kiwifruit is popular with consumers because it has a pleasant taste and texture, and because, being approximately 90% water, it is low in energy. It is also viewed as a “healthy” food: it is nutrient dense, containing complex carbohydrates and dietary fiber, as described in earlier chapters of this volume. Kiwifruit are relatively rich in minerals and other nutrients compared with other fruits. (Note: In this chapter, “kiwifruit” generally refers to green kiwifruit, Actinidia deliciosa cv.

▲Kiwi Pollen

猕猴桃中的矿物质
猕猴桃之所以受到消费者的欢迎，是因为它有着令人愉悦的味道和质地，而且因为它含有约90%的水分，能量低。它也被视为一种“健康”食品：它营养丰富，含有复合碳水化合物和膳食纤维，如本卷前几章所述。与其他水果相比，猕猴桃富含矿物质和其他营养物质。（注：在本章中，“猕猴桃”一般是指绿色猕猴桃，美味猕猴桃品种。
Kiwifruit Components Facilitate Mineral Uptake
For an individual to obtain all the essential nutrients, it is recommended that nutrient-dense foods are included in the diet. Components in food may influence dietary mineral absorption. Ideal foods are both nutrient dense and contain bioactive factors that enhance mineral absorption.
The mechanism by which ascorbic acid enhances iron absorption is well established (Fairweather-Tait, 1995). As kiwifruit is a rich source of ascorbic acid, consuming kiwifruit with a dietary source of iron has the

▲红心猕猴桃种植

猕猴桃成分促进矿物质吸收
为了使个人获得所有必需营养素，建议在饮食中加入营养丰富的食物。食物中的成分可能会影响膳食矿物质的吸收。理想的食物既营养丰富，又含有增强矿物质吸收的生物活性因子。
抗坏血酸增强铁吸收的机制已经得到很好的证实（Fairweather-Tait，1995）。由于猕猴桃富含抗坏血酸，食用含有铁的猕猴桃会产生

▲New Zealand's newly built Sunshine Golden Fruit Orchard

Conclusions
Kiwifruit is a nutrient-dense food, containing nutritionally significant amounts of several key micronutrients often found to be deficient, even in high-energy Western diets. High levels of ascorbic acid in kiwifruit have been shown to aid mineral uptake and retention both in vitro and in vivo. Consumption of kiwifruit can therefore make an important contribution to an individual's diet and health.

结论
猕猴桃是一种营养丰富的食物，含有大量营养丰富的几种关键微量营养素，即使在高能量的西方饮食中也是如此。猕猴桃中高水平的抗坏血酸已被证明有助于体外和体内矿物质的吸收和保留。因此，食用猕猴桃可以对个人的饮食和健康做出重要贡献。

▲贵州高山金果猕猴桃

▲Zunyi Bohong Kiwi Fruit Industry Co., Ltd. is the largest kiwi fruit industry company in Guizhou Province, planting 1200 acres of high-altitude kiwifruit. It is a leading agricultural enterprise in Zunyi City and an advanced poverty alleviation enterprise at the municipal level. The kiwi pollen project is the largest single area macaque peach blossom pollen orchard in China, with a single pollen collection area of 400 acres. During the high-yield period, 400 kilograms of pollen are produced, providing high-quality, high ploidy, and high activity kiwi pollen that can meet the pollen needs of 30000 acres of orchards. Contact WeChat 18030405084 tel 86 18030405084