富硒植物与人体健康

硒是生态环境中的一个重要微量元素。1957年施瓦茨发现,硒有抗氧化作用,并首次提出硒是人体的必需元素。同年,谷跳甘肽过氧化物酶被发现。1971年,Rotz－uch证明,硒是该酶的组成成分。1973年,世界卫生组织宣布硒是人体生命的必需元素。近年,德国植物营养学家已将硒列于植物有益元素的行列。硒通过生物地球化学营养链：岩石一土壤和水一植物一动物和人给人和动物以影响。几十年来的研究结果表明,人和动物的四十多种疾病与体内硒缺乏有关,典型疾病如地方性克山病、大骨节病、牲畜的白肌病。禽类的渗出性素质等,而硒制剂对这些疾病均…     

人体硒代谢与硒营养研究进展

硒是人体所必需的重要微量营养元素,综述了当前国内外人体硒代谢与硒营养的研究进展,包括硒源形式与吸收、人体的硒含量与分布、硒的代谢途径、硒的生物活化形式、硒与疾病、硒中毒和硒的安全摄入量。在此基础上,提出了针对我国硒资源分布、硒反应症分布和居民膳食结构硒摄入量的研究建议,为满足居民通过膳食和补充剂补硒预防和治疗疾病提供理论和实践指导。     

水的营养与人体健康

1　水的重要作用水不仅有营养 ,而且它在人的生活中是非常重要的营养素。在 7大营养素中 ,水被国际营养学界列为首位。一个人 ,不给任何食物 ,只供饮水 ,最长能活 59天。相反 ,如果不供水 ,只给食物 (食物中的水被除掉 ) ,一般 5天即死 ,最长记录只活 17天。可见 ,水比任何营养物质都重要。由于地震等原因 ,人若被埋在地下时 ,只要想法能喝到一些水 ,就能维持较长的生命。为什么水在人的生活中那么重要呢 ?这是因为 :1)水是一切营养素和代谢废物的溶剂 ,体内没有充足的水分 ,一切营养物质 ,就不能被溶解吸收和利用 ,废物也不能被排出 ,生命…     

土壤硒及其与植物硒营养的关系

综述了土壤中Se的形态分布、有效性及其与植物关系研究方面的进展。论述了不同形态的Se在土壤中分布情况、对植物的有效性与土壤pH值、化学及矿物学组成、吸附表面、氧化还原状态等物理化学性质的关系;Se在植物中的富集、转化及其对植物的抗氧化、促进生长、提高产量和质量等各种生物学效应;并在此基础上对Se的应用前景做了展望。     

人体发硒水平影响因素研究进展

利用头发无损、便捷、安全地监测身体中微量元素硒水平状况,具有重要的健康意义。综述了膳食硒摄入量、健康状况、性别、年龄等因素对人体头发中硒含量的影响,为利用发硒水平监测人体硒水平与健康状况提供了科学参考与依据。     

保健饮料与人体健康

保健饮料是属于保健食品的一部分,目前国际上尚无统一的定义。重点阐述了国际、国内公认的八类保健饮料的主要成分、特点及其与人体健康的密切关系。指出了我国目前保健饮料存在的主要问题。     

马铃薯抗营养因子与人体健康

综述马铃薯抗营养因子的营养价值及对新育种体系的需求。通过利用现存的种质资源,结合二倍育种和基因编辑等新技术手段可以进一步改善未来的品种并提供其他选择,以帮助满足不断变化的市场需求。     

Selenium in human nutrition: dietary intakes and effects of supplementation

The dietary selenium intakes of a young couple residing in Southern California were determined to be 107 and 99 micrograms/day for the husband and the wife, respectively, on the basis of a 30 day study. For other young adult Californians, the selenium intakes were estimated from 90 to 168 micrograms/day. The highest intakes were observed in individuals subsisting on diets rich in whole wheat grain cereal products and seafoods. The selenium concentrations in whole blood of the subjects under study correlated with the dietary selenium intakes directly (P less than 0.001). The administration of 150 micrograms of selenium/day in the form of commercially available supplements increases the blood selenium concentrations. After 3 weeks of supplementation, the selenium concentrations in whole blood of our subjects reached 0.21 micrograms/ml. Prolonged supplementation at higher Se dosage levels causes further increases of the blood concentrations: Two individuals who had been ingesting 350 and 600 micrograms/day for 18 months exhibited blood selenium levels of 0.35 and 0.62 micrograms/ml. The blood selenium concentration of all subjects declined slowly after cessation of supplementation. Selenium uptake from the supplements was not affected by the joint administration of zinc supplements at 15 mg zinc/day. Glutathione peroxidase blood levels did not correlate with blood Se concentrations.     

Selenium in total parenteral nutrition

In clinical practice, selenium deficiency may arise under conditions of chronic malnutrition and especially after long-term total parenteral nutrition (TPN). In infants receiving long-term TPN, we observed plasma selenium levels as low as those previously reported in Chinese children with Keshan disease. Low plasma selenium levels were also usually associated with very low activities of glutathione peroxidase. Although clinical symptoms of selenium deficiency did not occur in our patients, several cases have been described in the literature, indicating the need for supplementation in TPN. In order to derive at the appropriate dosage, it is proposed to correlate it with the total protein supply. According to our present knowledge, .5–1.0 μg selenium/g of protein appears to be adequate to keep patients in Se balance. For Se repletion of body stores, this dosage has been increased up to 3 μg of Se/g of protein. Advantages and disadvantages of selenite and of selenomethionine as possible supplemental forms of Se for TPN solutions are discussed.     

Phytoferritin and its implications for human health and nutrition

Background

Plant and animal ferritins stem from a common ancestor, but plant ferritins exhibit various features that are different from those of animal ferritins. Phytoferritin is observed in plastids (e.g., chloroplasts in leaves, amyloplasts in tubers and seeds), whereas animal ferritin is largely found in the cytoplasm. The main difference in structure between plant and animal ferritins is the two specific domains (TP and EP) at the N-terminal sequence of phytoferritin, which endow phytoferritin with specific iron chemistry. As a member of the nonheme iron group of dietary iron sources, phytoferritin consists of 24 subunits that assemble into a spherical shell storing up to ∼ 2000 Fe^3 + in the form of an iron oxyhydroxide-phosphate mineral. This feature is distinct from small molecule nonheme iron existing in cereals, which has poor bioavailability.

Scope of review

This review focuses on the relationship between structure and function of phytoferritin and the recent progress in the use of phytoferritin as iron supplement.

Major conclusions

Phytoferritin, especially from legume seeds, represents a novel alternative dietary iron source.

General significance

An understanding of the chemistry and biology of phytoferritin, its interaction with iron, and its stability against gastric digestion is beneficial to design diets that will be used for treatment of global iron deficiency.     

Haematococcus astaxanthin: applications for human health and nutrition

The carotenoid pigment astaxanthin has important applications in the nutraceutical, cosmetics, food and feed industries. Haematococcus pluvialis is the richest source of natural astaxanthin and is now cultivated at industrial scale. Astaxanthin is a strong coloring agent and a potent antioxidant - its strong antioxidant activity points to its potential to target several health conditions. This article covers the antioxidant, UV-light protection, anti-inflammatory and other properties of astaxanthin and its possible role in many human health problems. The research reviewed supports the assumption that protecting body tissues from oxidative damage with daily ingestion of natural astaxanthin might be a practical and beneficial strategy in health management.     

Toward the implementation of metabolomic assessments of human health and nutrition

Metabolomics is emerging as an exciting post-genomic science with applications that span the scope of biotechnology and medicine. Although metabolomics is still in its infancy, it has already been used to identify the function of genes, describe the effects of toxicological, pharmaceutical, nutritional and environmental interventions, and to build integrated databases of metabolite concentrations across human and research animal populations. Metabolomics provides nutrition with an invaluable tool for determining the distributions of metabolite concentrations in humans, the relationship of these metabolite concentrations to disease, and the extent to which nutrition can modulate metabolite concentrations.     

Selenium depletion in patients on home parenteral nutrition

Severe selenium (Se) depletion was found in nine patients receiving long-term home parenteral nutrition because of short bowel syndrome. Plasma Se ranged from 0–0.51 (median 0.21 μmol/L) and erythrocyte Se ranged from 0.7–2.6 (median 1.8 μmol/gHgb), which was significantly lower than in the controls. Glutathione peroxidase (GSHPx) in plasma and erythrocytes was also decreased. After bolus injections with 200 μg Se/d in the form of sodium selenite for 4 mo, followed by 100 μg/d for 8 mo, plasma Se increased to values slightly but significantly higher than in the controls. Erythrocyte Se reached normal levels in most of the patients after 4 mo substitution, but it remained lower than in the controls. Following Se supplementation, plasma and erythrocyte GSHPx did not differ between patients and controls. These data suggest that all patients receiving long-term parenteral nutrition because of short bowel syndrome should receive at least 100 μg sodium selenite/d when given as bolus injections to avoid Se depletion.     

Phenotypic flexibility as key factor in the human nutrition and health relationship

Metabolic adaptation to a disturbance of homeostasis is determined by a series of interconnected physiological processes and molecular mechanisms that can be followed in space (i.e., different organs or organelles) and in time. The amplitudes of these responses of this “systems flexibility network” determine to what extent the individual can adequately react to external challenges of varying nature and thus determine the individual’s health status and disease predisposition. Connected pathways and regulatory networks act as “adaptive response systems” with metabolic and inflammatory processes as a core—but embedded into psycho-neuro-endocrine control mechanisms that in their totality define the phenotypic flexibility in an individual. Optimal metabolic health is thus the orchestration of all mechanisms and processes that maintain this flexibility in an organism as a phenotype. Consequently, onset of many chronic metabolic diseases results from impairment or even loss of flexibility in parts of the system. This also means that metabolic diseases need to be diagnosed and treated from a systems perspective referring to a “systems medicine” approach. This requires a far better understanding of the mechanisms involved in maintaining, optimizing and restoring phenotypic flexibility. Although a loss of flexibility in a specific part of the network may promote pathologies, this not necessarily takes place in the same part because the system compensates. Diagnosis at systems level therefore needs the quantification of the response reactions of all relevant parts of the phenotypic flexibility system. This can be achieved by disturbing the homeostatic system by any challenge from extended fasting, to intensive exercise or a caloric overload.