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1.
《Field Crops Research》1999,60(1-2):93-113
Within the scientific agricultural community it is widely known that the total micronutrient content of soils is not a useful measure of the amount of `available' micronutrients to plants. Thus, soil tests have been developed to determine the amounts of micronutrients in soils available to plants for growth. This same concept applies to plant foods eaten by humans because not all of the micronutrients in plant foods are available (i.e. bioavailable) for absorption and or utilization. Antinutrients and promoter substances within plant foods that can either inhibit or enhance the absorption and/or utilization of micronutrients when eaten. As a result, numerous techniques have been developed to determine the amounts of bioavailable micronutrients present in plant foods when consumed in mixed diets with other dietary constituents that can interact and affect the micronutrient bioavailability. Unfortunately, micronutrient bioavailability to humans fed mixed diets is still a confusing and complex issue for the human nutrition community. Our understanding of the processes that control micronutrient bioavailability from mixed diets containing plant foods is relatively limited and still evolving. It remains the subject of extensive research in many human nutrition laboratories globally. This article reviews some of the numerous methodologies that have arisen to account for the bioavailability of micronutrients in plant foods when eaten by humans. 相似文献
2.
《Journal of Crop Improvement》2013,27(1-2):31-53
SUMMARY This chapter reviews current knowledge and experience with using food-based approaches in reducing vitamin A and iron deficiencies. It reviews recently published literature, highlights some lessons learned, and identifies knowledge gaps and research priorities. The main strategies reviewed are food-based interventions that aim at: (1) increasing the production, availability, and access to vitamin A and iron-rich foods through the promotion of home production and (2) plant breeding strategies that have the potential to increase the content of vitamin A and iron in diet as well as their bioavailability. The review highlights the fact that significant progress has been achieved in the past few decades in the design and implementation of food-based approaches. Evaluations however remain weak, and without rigorous, carefully conducted evaluations the real potential of food-based approaches in addressing micronutrient malnutrition cannot be fully understood. Plant breeding strategies, although they are at a much earlier stage of development, hold great promise because of their enormous potential to improve the dietary quality of populations relying mainly on cereal staples. Studies on human bioavailability are the next crucial step to help understand the potential contribution of plant breeding towards alleviating micronutrient malnutrition. Our review suggests that food-based interventions could be an essential part of the long-term global strategy for the fight against micronutrient malnutrition, but their real potential is still to be explored. 相似文献
3.
《Journal of Crop Improvement》2013,27(1):87-131
Summary Within the last three decades, the rice-wheat cropping system has triggered, and with time, aggravated soil micronutrient deficiencies in the Indo-Gangetic Plains (IGP). This has largely been due to the shift from an earlier rice and wheat monoculture with low yielding, long duration indigenous varieties, to an intensive rice-wheat rotation cropping system with short duration modern high yielding varieties on the same piece of land. The problems related to micronutrient deficiency in the IGP are more due to the size of its available pools in the soil rather than its total contents and are greatly influenced by crop management, or rather its mismanagement. Deficiency of zinc is widespread in the IGP, but with the extensive use of zinc sulfate, zinc deficiency has reduced in some areas of the region. Meanwhile, the deficiency of Fe, Mn and B has increased in the IGP. Deficiency of Cu and Mo is location specific and can limit rice and wheat yields. The adoption and spread of the rice-wheat system in permeable coarse textured soils, particularly in the western IGP, not only caused iron deficiency in rice but also resulted in the emergence of manganese deficiency in wheat. In highly calcareous and acidic soils, boron is the next limiting micronutrient in crop production after zinc. Bumper rice and wheat harvests in the past decade, the declining use of organic manures in the region and except for the widespread use of zinc sulfate, a general lack of awareness amongst farmers on micronutrient deficiency problems has contributed to micronutrients limiting rice and wheat yields in the IGP. Approaches to alleviating micronutrient deficiencies include matching the crop removals of the micronutrients with its replenishments through their respective external carriers, supplementation through organic sources and mobilization/utilization through cultivation of micronutrient efficient crop cultivars. Identification of efficient micronutrient carriers and finding the optimum rate, mode and time of its application is important in ameliorating the micronutrient deficiencies. This article reviews the extent of micronutrient deficiency and discusses various management options available to reduce micronutrient deficiency induced crop yield reduction for rice and wheat in the Indo-Gangetic Plains. 相似文献
4.
《Journal of Crop Improvement》2013,27(1-2):119-144
SUMMARY More than twenty cropping systems are practiced in India. Rice-wheat and rice-rice are the major cropping systems practiced in an estimated 120 districts and 50 districts of the country, respectively. The rice-wheat cropping system (RWCS) of the Indo-Gangetic Plains (IGP) region of South Asia (Bangladesh, India, Nepal, and Pakistan) is the creation of the agricultural green revolution. Higher production of rice and wheat was necessary to meet the calorie needs of an increasing population in this region; as a result, the percent of malnutrition amongst children and adults decreased during the green revolution era. However, in recent years, there has been a reduction in both the rate of malnutrition decline and of the partial and total factor productivity of the RWCS in India. One of the many reasons for the decreased rate of malnutrition decline is micronutrient deficiency. Malnutrition amongst children and adults is a silent emergency in South Asia, including India. This review compares the food consumption habits, nutritional status, and cropping system practiced for different states of India to provide reasons for shifting the rice-wheat cropping system through crop diversification. Diversification of the RWCS will increase the supply of legumes and vegetables, help to diversify the diets consumed, and increase micronutrient intake. This approach is important for a largely vegetarian population of India, and is therefore, considered to be one of several important Food Systems strategy to address the silent emergency of malnutrition in the region. 相似文献
5.
J.I. Ortiz-Monasterio N. Palacios-Rojas E. Meng K. Pixley R. Trethowan R.J. Pea 《Journal of Cereal Science》2007,46(3):293
More than half of the world's population suffers micronutrient undernourishment. The main sources of vitamins and minerals (iron, zinc, and vitamin A) for low-income rural and urban populations are staple foods of plant origin that often contain low levels or low bioavailability of these micronutrients. Biofortification aims to develop micronutrient-enhanced crop varieties through conventional plant breeding. HarvestPlus, the CGIAR's biofortification initiative, seeks to breed and disseminate crop varieties with enhanced micronutrient content that can improve the nutrition of the “hard to reach” (by fortification or supplementation programmes) rural and urban poor in targeted countries/regions. In attempting to enhance micronutrient levels in maize and wheat through conventional plant breeding, it is important to identify genetic resources with high levels of the targeted micronutrients, to consider the heritability of the targeted traits, to explore the availability of high throughput screening tools and to gain a better understanding of genotype by environment interactions. Biofortified maize and wheat varieties must have the trait combinations which encourage adoption such as high yield potential, disease resistance, and consumer acceptability. When defining breeding strategies and targeting micronutrient levels, researchers need to consider the desired micronutrient increases, food intake and retention and bioavailability as they relate to food processing, anti-nutritional factors and promoters. Finally, ex ante studies are required to quantify the burden of micronutrient deficiency and the potential of biofortification to achieve a significant improvement in human micronutrient status in the deficient target population in order to determine whether a biofortification program is cost-effective. 相似文献
6.
《Journal of Cereal Science》2008,47(3):293-307
More than half of the world's population suffers micronutrient undernourishment. The main sources of vitamins and minerals (iron, zinc, and vitamin A) for low-income rural and urban populations are staple foods of plant origin that often contain low levels or low bioavailability of these micronutrients. Biofortification aims to develop micronutrient-enhanced crop varieties through conventional plant breeding. HarvestPlus, the CGIAR's biofortification initiative, seeks to breed and disseminate crop varieties with enhanced micronutrient content that can improve the nutrition of the “hard to reach” (by fortification or supplementation programmes) rural and urban poor in targeted countries/regions. In attempting to enhance micronutrient levels in maize and wheat through conventional plant breeding, it is important to identify genetic resources with high levels of the targeted micronutrients, to consider the heritability of the targeted traits, to explore the availability of high throughput screening tools and to gain a better understanding of genotype by environment interactions. Biofortified maize and wheat varieties must have the trait combinations which encourage adoption such as high yield potential, disease resistance, and consumer acceptability. When defining breeding strategies and targeting micronutrient levels, researchers need to consider the desired micronutrient increases, food intake and retention and bioavailability as they relate to food processing, anti-nutritional factors and promoters. Finally, ex ante studies are required to quantify the burden of micronutrient deficiency and the potential of biofortification to achieve a significant improvement in human micronutrient status in the deficient target population in order to determine whether a biofortification program is cost-effective. 相似文献
7.
8.
《Journal of Crop Improvement》2013,27(1):133-165
Summary Results of field experiments across the Indo-Gangetic Plains (IGP) region indicates that soil B deficiency induces sterility in wheat and results in poor crop yields of legumes and cereals. The deficiency of soil B and the response of crops to applied B generally increases from the northwestern to the eastern end of the IGP, this trend being influenced by the distribution of the soil parent material and the variation in the climatic conditions within the IGP. An earlier FAO study rated Nepal as the lowest of thirty countries in its soil B status and showed that a higher soil B deficiency problem exists in the eastern half of the Indian-IGP, therefore crop response to applied B is more likely in these areas. Few studies have made qualitative and quantitative assessment of sterility in wheat in the IGP and the positive response of other crops to B application also suggest B deficiency related sterility problems in these crops. Micronutrient research in the IGP often rates Zn followed by Fe and Mn deficiencies in some instances, as its major soil micronutrient deficiency problems. However, the deficiency of B perhaps is as important if not more, than Fe and Mn deficiency. The awareness of soil B deficiency is not as widespread as its occurrence in the IGP region. This article reviews and discusses the sterility problems in wheat and the response of several field crops to applied B to highlight the growing importance of soil B deficiency in the IGP. 相似文献
9.
《Field Crops Research》1999,60(1-2):165-173
The combining of benefits for human nutrition and agricultural productivity, resulting from breeding staple food crops which are more efficient in the micronutrient metal uptake from the soil, and which accumulate more micronutrients into their seeds, results in extremely high ex ante estimates of benefit/costs ratios for investments in agricultural research in this area. This finding derives from the confluence of several complementary factors:
- •Rates of micronutrient malnutrition are high in developing countries, as are the consequent costs to human welfare and economic productivity.
- •Because staple foods are eaten in large quantities every day by the malnourished poor, delivery of enriched staple foods (fortified by the plants themselves during growth) can rely on existing consumer behavior.
- •A significant percentage of the soils in which these staple foods are grown are `deficient' in these micronutrient metals, which has kept crop yields low. In general, these soils in fact contain relatively high total amounts of micronutrient metals. However, because of binding to soil constituents, these nutrients have poor soil availability to staple crop varieties that are currently available to farmers.
- •Adoption and spread of nutritionally-improved varieties by farmers can rely on profit incentives, either because of agronomic advantages on trace mineral-deficient soils or incorporation of nutritional improvements in the most productive varieties being released by agricultural research stations.
- •Benefits to relatively small investments in agricultural research may be disseminated widely, potentially accruing to hundreds of millions of people and millions of hectares of cropland.
- •Benefits from breeding advances, derived from initial, fixed costs, typically do not involve high recurring costs, and thus tend to be highly sustainable as long as an effective domestic agricultural research infrastructure is maintained.
10.
《Field Crops Research》1999,60(1-2):11-26
Soils vary widely in their micronutrient content and in their ability to supply micronutrients in quantities sufficient for optimal crop growth. Soils deficient in their ability to supply micronutrients to crops are alarmingly widespread across the globe, and this problem is aggravated by the fact that many modern cultivars of major crops are highly sensitive to low micronutrient levels. Original geologic substrate and subsequent geochemical and pedogenic regimes determine total levels of micronutrients in soils. Total levels are rarely indicative of plant availability, however, because availability depends on soil pH, organic matter content, adsorptive surfaces, and other physical, chemical, and biological conditions in the rhizosphere. Micronutrient availability to plants can be measured in direct uptake experiments, or estimated with techniques that correlate quantities of micronutrients extracted chemically from soils to plant uptake and response to micronutrient fertilization. Rational management of micronutrient fertility and toxicity requires an understanding of how total and plant-available soil micronutrients vary across the land. A variety of approaches have been used to survey and map the geographic distribution of soil micronutrient content and availability at scales ranging from global to sites within single production fields. Soil micronutrient maps covering large areas improve our understanding of the nature and extent of micronutrient problems, and aid in determining their relationships with climate, soil properties, and soil genetic characteristics determined at similar scales, for example, Soil Taxonomy to the order, sub-order, or great group levels. Intermediate scale maps can be useful in delineating specific areas where deficiencies or toxicities are likely for agriculture, and in determining localized soil characteristics that may be associated with such problems. Highly detailed maps of soil micronutrient content and availability in individual fields are being developed for site-specific precision agriculture. Soil micronutrient maps have fostered discovery of relationships between soil micronutrient content and availability and some human and livestock health problems such as goiter, Keshan and Kaschin–Beck diseases, and cancer. Advances including the global positioning system (GPS), geographic information systems (GIS), inductively coupled plasma (ICP) spectrometry, geostatistics, and precision agriculture facilitate soil micronutrient mapping and provide quantitative support for decision and policy making to improve agricultural approaches to balanced micronutrient nutrition. 相似文献
11.
《Journal of Crop Improvement》2013,27(1-2):339-363
SUMMARY Fortification of foods has been a successful strategy for the delivery of micronutrients in developed countries. Fortification requires modest investments, is cost effective, can build on existing technologies facilitated by the globalization of the food industry, supports other public health strategies to combat micronutrient deficiency induced malnutrition, and enhances sustainability. In developing countries, the success of food fortification has been encouraging, but varied, due to the decentralized food processing process and issues of quality control. Food fortification is an integral part of any food systems strategy and the choice of the appropriate food vehicle and its fortificant can be tailored to meet the local needs. This article discusses various aspects of food fortification: existing and future opportunities for food fortification, cost effectiveness, food fortification success stories with examples from different regions, and impact on nutritional status of humans. 相似文献
12.
Iron Uptake and Loading into Rice Grains 总被引：3，自引：1，他引：2
Iron (Fe) is an important micronutrient for living organisms. Fe deficiency severely impairs plant growth and is a widespread human dietary problem, with particularly high numbers of affected children and females. Rice (Oryza sativa) is a source of energy for more than half of the world’s population. Thus, understanding the mechanisms of Fe uptake and translocation in rice is of utmost importance in the development of rice varieties that are tolerant to low Fe availability and with high seed levels of Fe. In recent years, the mechanisms underlying Fe transport and homeostasis have been revealed, providing opportunities to increase the Fe content of rice grain. As excess Fe is toxic to cells, plants have developed sophisticated mechanisms to control Fe flow, making it difficult to alter Fe transport. Thus, choosing appropriate chelators and Fe transporters driven by appropriate promoters seems to be the key in developing rice that is tolerant to low Fe availability and which accumulates high grain levels of Fe. Many recent studies have been aimed at increasing the Fe content of rice. Here, we summarize these efforts and review recent progress in understanding the mechanisms of Fe transport. 相似文献
13.
Lectins are carbohydrate-binding proteins present in most plants. They play a role in protecting plants against external pathogens, like fungi, and other organisms. Some common dietary staples, such as cereal grains and legumes, have relatively high concentrations of a variety of lectins. A part of the proteins present in wheat germ is characterized as wheat germ agglutinin (WGA), in this respect. Authors of popular nutritional plans propose adverse health effects of this wheat lectin. With the use of different arguments, the consumption of foods high in lectins is discouraged. In this context, we discuss the effects of lectins from wheat on human health. Up-to-date research findings on mechanisms that wheat lectins have effects on health factors, such as obesity, autoimmune disease, and celiac disease, are critically reviewed. We conclude that there are many unsubstantiated assumptions made. Current data about health effects of dietary lectins, as consumed in cooked, baked, or extruded foods do not support negative health effects in humans. In contrast, consumption of WGA containing foods, such as cereals and whole grain products, has been shown to be associated with significantly reduced risks of type 2 diabetes, cardiovascular disease, some types of cancer, as well as a more favourable long-term weight management. Research is recommended to define actual active lectin contents in wheat-based foods after heat preparation for human consumption. 相似文献
14.
Dr. C. E. Bodwell 《Plant foods for human nutrition (Dordrecht, Netherlands)》1979,29(1-2):135-162
In most countries of the third world, foods of plant origin are the primary sources of dietary protein; in many of these countries, dietary protein often is supplied solely from plant sources. Under these conditions, the nutritive value of the protein in the diets may be low due to amino acid deficiencies or imbalances. Alternately if the protein level is low in the plant sources, then the total amount of dietary protein may be inadequate. Various approaches have been used to increase the amount of utilizable protein. Those discussed include amino acid fortification, uses of protein mixtures (protein supplementation and complementation), and genetic alterations of food crops. The need for nutritional improvement of plant proteins is considered in relation to the current questions about protein requirements and the adequacy of plant foods in meeting protein requirements. The dependence for success of any protein-improvement upon non-nutritional, socio-economic factors is noted. 相似文献
15.
《Journal of Crop Improvement》2013,27(2):165-195
Summary Micronutrient fertilizer sources are mostly sulfates for Zn, Cu, and Mn, but chelates are the usual Fe source, and borax and sodium molybdate are used for B and Mo, respectively. Soil pH is the soil property that most influences micronutrient availability, and for all but Mo, the higher the soil pH, the lower is the plant availability. For Mo, liming can actually prevent deficiencies. Other soil properties that are important in bioavailability are organic matter content, especially for Cu, oxidation/reduction conditions, especially for Fe and Mn, soil texture, Fe and Al oxide content and soil moisture conditions. 相似文献
16.
Rice-wheat cropping system(RWCS) is one of the most important cropping systems in South Asia. However, sustainability of this system is under threat owing to several factors, of which deficiency of micronutrients particularly zinc(Zn), boron(B) and manganese(Mn) is one of the major problems. Continuous rotation of rice and wheat, imbalanced fertilizer use and little/no use of micronutrient-enriched fertilizers induce deficiencies of Zn, B and Mn in the RWCS of South Asia. Here we review that(i) imbalanced fertilizer use and organic matter depletion deteriorate soil structure resulting in low efficiency of applied macro-and micro-nutrients in RWCS.(ii) The micronutrients(Zn, B and Mn) are essentially involved in metabolism of rice and wheat plants, including chlorophyll synthesis, photosynthesis, enzyme activation and membrane integrity.(iii) Availability and uptake of Zn, B and Mn from rhizosphere depend on the physico-chemical soil properties(which differ under aerobic and anaerobic conditions) including soil p H, soil organic matter, soil moisture and interaction of these micronutrients with other nutrients.(iv) Plant ability to uptake and utilize the nutrients is affected by several plant factors such as root architecture, root hairs, transport kinetics parameter and root exudates.(v) Crop management and application of these microelements can help correct the micronutrients deficiency and enhance their grain concentration. 相似文献
17.
《Field Crops Research》1999,60(1-2):115-141
Plant foods can be improved as sources of essential micronutrients either by increasing the concentrations of nutrients in the food, increasing the bioavailability of micronutrients in the food, or both of these. Quantities of minerals in edible portions of crops are influenced by numerous complex, dynamic and interacting factors, including plant genotype, soil properties, environmental conditions and nutrient interactions. Similarly, numerous dietary and host factors interact to affect the bioavailability to animals and people of mineral nutrients in plant foods. Micronutrient bioavailability apparently can be improved by either increasing the quantity of substances within plant foods that enhance the absorption and utilization of micronutrients or by decreasing the quantity of dietary antinutrients that inhibit micronutrient absorption; however, processes that control and regulate the bioavailability of trace elements in plant foods consumed in mixed diets are not fully understood. Use of either stable or radioactive isotopes incorporated intrinsically into edible portions of plant foods during plant growth will likely provide the most reliable estimates of the bioavailability of micronutrients consumed in mixed diets. Increasing the dietary supply of staple plant foods rich in trace elements combined with increased knowledge of micronutrient bioavailability from these foods will meaningfully improve the nutritional health and well being of people. 相似文献
18.
《Journal of Crop Improvement》2013,27(1-2):145-176
SUMMARY Vegetables are a major source of dietary micronutrients, but abiotic and biotic constraints limit vegetable production and consumption in Asia. Per capita vegetable consumption in Asia is far below the required level to satisfy the recommended dietary micronutrient intakes. Empirical evidence and discussion in this article show that enhanced vegetable production and consumption in Asia can play a catalytic role in the overall economic development by improving the nutritional status, learning capabilities and managerial capacities of farmers, generating incomes and jobs in both the farm and non-farm sectors, and improving resource use efficiency in agriculture. Rapid urbanization, higher incomes, and greater awareness amongst consumers and producers to diversify their food and production systems have increased the demand for vegetables in Asia. To realize this potential demand, especially during the off-season of vegetable production, trade-oriented and production enhancement strategies are suggested in this article. The trade-oriented policies can help link the favorable vegetable producing areas with consumption centers, and production oriented policies can overcome the biotic and abiotic constraints of vegetable production by developing economically viable, socially acceptable, and environmentally friendly technologies. Both the strategies require government support and increased allocation of research funds and manpower for vegetable cultivation. Government policies to stabilize vegetable production and trade, can mitigate the risk inherit in vegetable production. 相似文献
19.
Katie L. Moore Fang-Jie Zhao Cristina S. Gritsch Paola Tosi Malcolm J. Hawkesford Steve P. McGrath Peter R. Shewry Chris R.M. Grovenor 《Journal of Cereal Science》2012
Insufficient iron (Fe) is one of the most prevalent micronutrient deficiencies in humans, with billions of people affected. Cereal grains are an important source of Fe for humans but the bioavailability of Fe in cereals is generally low. Information regarding the cellular and sub-cellular localisation of Fe in wheat grain will aid optimising nutrient delivery for human health. In this study high resolution secondary ion mass spectrometry (NanoSIMS) was used to map the distribution of Fe in the aleurone layer and in the endosperm of immature wheat grain. Iron was shown to be localised strongly in the phytin globoids in the aleurone cells and to a lesser extent in the cytoplasm around the starch granules in the endosperm. 相似文献
20.
Developments in genetics, agronomics and processing has positioned staple cereals as important sources of iron, zinc and provitamin A (pVA) carotenoids for nutritionally vulnerable populations. Significant effort has been placed on understanding the bioavailability of these micronutrients from cereal foods, including the exploration of underlying mechanisms by which their bioavailability can be modified. While micronutrient bioavailability is preferably assessed in clinical trials, relevant in vitro digestion and intestinal cell culture models have been applied to study effects of genetic, agronomic, post-harvest and food processing on micronutrient bioavailability. This review (1) critically assesses the application of in vitro models in the exploration of mechanisms associated with iron, zinc and provitamin A carotenoid bioaccessibility and intestinal absorption from cereal foods, and (2) identifies remaining gaps in order to frame future strategies to improve the nutritional impact of cereal foods. 相似文献