Interaction of chemical species with biological regulation of the metabolism of essential trace elements

Variations in the chemical speciation of dietary trace elements can result in the provision of different amounts of these micronutrients to the organism and might thus induce interactions with trace-element metabolism. The chemical species of Zn, Fe, Cu, and Mn can interact with other components of the diet even before reaching the site of absorption, e.g. by formation of poorly soluble complexes with phytic acid. This might considerably modify the amount of metabolically available trace elements; differences between absorptive capacity per se toward dietary species seems to be less important. Homeostasis usually limits the quantities of Zn, Fe, Cu, and Mn transported from the gut into the organism, and differences between dietary species are largely eliminated at this step. There is no homeostatic control of absorption of Se and I, and organisms seem to be passively exposed to influx of these micronutrients irrespective of dietary speciation. Inside the organism the trace elements are usually converted into a metabolically recognizable form, channeled into their biological functions, or submitted to homeostatically controlled excretion. Some dietary species can, however, be absorbed as intact compounds. As long as the respective quantities of trace elements are not released from their carriers, they are not recognized properly by trace element metabolism and might induce tissue accumulation, irrespective of homeostatic control.     

High Endogenously Synthesized N-3 Polyunsaturated Fatty Acids in Fat-1 Mice Attenuate High-Fat Diet-Induced Insulin Resistance by Inhibiting NLRP3 Inflammasome Activation via Akt/GSK-3β/TXNIP Pathway

High-fat (HF) diets and low-grade chronic inflammation contribute to the development of insulin resistance and type 2 diabetes (T2D), whereas n-3 polyunsaturated fatty acids (PUFAs), due to their anti-inflammatory effects, protect against insulin resistance. Interleukin (IL)-1β is implicated in insulin resistance, yet how n-3 PUFAs modulate IL-1β secretion and attenuate HF diet-induced insulin resistance remains elusive. In this study, a HF diet activated NLRP3 inflammasome via inducing reactive oxygen species (ROS) generation and promoted IL-1β production primarily from adipose tissue preadipocytes, but not from adipocytes and induced insulin resistance in wild type (WT) mice. Interestingly, endogenous synthesized n-3 polyunsaturated fatty acids (PUFAs) reversed this process in HF diet-fed fat-1 transgenic mice although the HF diet induced higher weight gain in fat-1 mice, compared with the control diet. Mechanistically, palmitic acid (PA), the main saturated fatty acid in an HF diet inactivated AMPK and led to decreased GSK-3β phosphorylation, at least partially through reducing Akt activity, which ultimately blocked the Nrf2/Trx1 antioxidant pathway and induced TXNIP cytoplasm translocation and NLRP3 inflammasome activation, whereas docosahexaenoic acid (DHA), the most abundant n-3 PUFA in fat-1 adipose tissue, reversed this process via inducing Akt activation. Our GSK-3β shRNA knockdown study further revealed that GSK-3β played a pivot role between the upstream AMPK/Akt pathway and downstream Nrf2/Trx1/TXNIP pathway. Given that NLRP3 inflammasome is implicated in the development of most inflammatory diseases, our results suggest the potential of n-3 PUFAs in the prevention or adjuvant treatment of NLRP3 inflammasome-driven diseases.     

Gallium Triggers Ferroptosis through a Synergistic Mechanism

The gallium ion (Ga³⁺) has long been believed to disrupt ferric homeostasis in the body by competing with iron cofactors in metalloproteins, ultimately leading to cell death. This study revealed that through an indirect pathway, gallium can trigger ferroptosis, a type of non-apoptotic cell death regulated by iron. This is exemplified by the gallium complex of the salen ligand ( Ga-1 ); we found that Ga-1 acts as an effective anion transporter that can affect the pH gradient and change membrane permeability, leading to mitochondrial dysfunction and the release of ferrous iron from the electron transfer chain (ETC). In addition, Ga-1 also targeted protein disulfide isomerases (PDIs) located in the endoplasmic reticulum (ER) membrane, preventing the repair of the antioxidant glutathione (GSH) system and thus enforcing ferroptosis. Finally, a combination treatment of Ga-1 and dietary polyunsaturated fatty acids (PUFAs), which enhances lipid peroxidation during ferroptosis, showed a synergistic therapeutic effect both in vitro and in vivo. This study provided us with a strategy to synergistically induce Ferroptosis in tumor cells, thereby enhancing the anti-neoplastic effect.     

Specific effect of polyunsaturated fatty acids on the cholesterol-poor membrane domain in a model membrane

To understand more fully the effect of polyunsaturated fatty acids (PUFAs) on lipid bilayers, we investigated the effects of treatment with fatty acids on the properties of a model membrane. Three kinds of liposomes comprising dipalmitoylphosphatidylcholine (DPPC), dioleylphosphatidylcholine (DOPC), and cholesterol (Ch) were used as the model membrane, and the fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) and detergent insolubility were determined. Characterization of the liposomes clarified that DPPC, DPPC/Ch, and DPPC/DOPC/Ch existed as solid-ordered phase (L beta), liquid-ordered phase (l o), and a mixture of l o and liquid-disordered phase (L alpha) membranes at room temperature. Treatment with unsaturated fatty acids such as oleic acid (OA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) markedly decreased the fluorescence anisotropy value and detergent insolubility. PUFAs and OA had different effects on the model membranes. In DPPC liposomes, the most prominent change was induced by PUFAs, whereas, in DPPC/Ch and DPPC/DOPC/Ch liposomes, OA had a stronger effect than PUFAs. The effect of PUFAs was strongly affected by the amount of Ch in the membrane, which confirmed a specific effect of PUFAs on the Ch-poor membrane domain. We further explored the effect of fatty acids dispersed in a water-in-oil-in-water multiple emulsion and found that unsaturated fatty acids acted on the membranes even when incorporated in emulsion form. These findings suggest that treatment with PUFAs increases the segregation of ordered and disordered phase domains in membranes.     

The synergistic chaperoning operation in a Bi-chaperone system consisting of alpha-crystallin and beta-casein: bovine pancreatic insulin as the target protein

While chaperone activity of alpha-crystallin (α-Crs) is important in maintaining lens transparency that of beta-casein (β-CN) is vital to prevent the development of corpora amylacea (accumulation of amyloid deposits in mammary glands). These two chaperone proteins are amphiphilic, each contains distinct polar and non-polar regions in the structure. While polar domain of α-Crs is highly electropositive, the counterpart domain in β-CN is strongly electronegative. In this study a Bi-chaperone system consisting of α-Crs and β-CN with different molar ratios were used to prevent the chemical-induced insulin aggregation spectroscopically. As shown, α-Crs and β-CN in the Bi-chaperone system exhibit synergistic chaperoning operation which strongly depends to the specific ratio of the chaperone components. The results of both fluorescence study and native gel electrophoresis confirmed the non-covalent interactions between α-Crs and β-CN. Consequently the synergistic activity can be explained with the possible electrostatic interactions between their polar/charged domains which bring them in close proximity, allowing their synergistic chaperoning operation in the Bi-chaperone system.     

重庆某地区居民膳食及发铁、血红蛋白含量分析

通过对重庆市某地区居民膳食结构和营养状况的调查,了解居民营养状况,特别是铁的营养状况。采用五日回顾法进行了膳食调查,氰化高铁血红蛋白法测定血红蛋白值及示波极谱法测定了发铁含量。结果表明,居民膳食蛋白质、多种维生素、矿物质摄入不足;贫血率为67.81%,发铁含量低于正常值的仅为6.70%。提示两地居民膳食属发展中国家模式,应调整膳食结构,增加豆类及动物性食物的摄入量,并增加含铁食物的摄入量,提高机体对铁的吸收和利用。     

The development and implementation of quality assurance programs to support nutritional measurements

The National Institute of Standards and Technology administers quality assurance programs devoted to improving measurements of nutrients and related metabolites in foods, dietary supplements, and serum and plasma samples. These programs have been developed in collaboration with the National Institutes of Health to assist measurement communities in their efforts to achieve accurate results that are comparable among different laboratories and over time. Targeted analytes include micronutrients, botanical markers, nutritional elements, contaminants, fatty acids, and vitamin D metabolites.     

The Action of Peroxyl Radicals,Powerful Deleterious Reagents,Explains Why Neither Cholesterol Nor Saturated Fatty Acids Cause Atherogenesis and Age‐Related Diseases

Cells respond to alterations in their membrane structure by activating hydrolytic enzymes. Thus, polyunsaturated fatty acids (PUFAs) are liberated. Free PUFAs react with molecular oxygen to give lipid hydroperoxide molecules (LOOHs). In case of severe cell injury, this physiological reaction switches to the generation of lipid peroxide radicals (LOO^.). These radicals can attack nearly all biomolecules such as lipids, carbohydrates, proteins, nucleic acids and enzymes, impairing their biological functions. Identical cell responses are triggered by manipulation of food, for example, heating/grilling and particularly homogenization, representing cell injury. Cholesterol as well as diets rich in saturated fat have been postulated to accelerate the risk of atherosclerosis while food rich in unsaturated fatty acids has been claimed to lower this risk. However, the fact is that LOO^. radicals generated from PUFAs can oxidize cholesterol to toxic cholesterol oxides, simulating a reduction in cholesterol level. In this review it is shown how active LOO^. radicals interact with biomolecules at a speed transcending usual molecule–molecule reactions by several orders of magnitude. Here, it is explained how functional groups are fundamentally transformed by an attack of LOO^. with an obliteration of essential biomolecules leading to pathological conditions. A serious reconsideration of the health and diet guidelines is required.     

平煤二小学生膳食状况调查

为了解平煤二小学生的膳食结构,合理安排学生膳食提供依据,用称重法对134名学生的膳食进行了5日的调查。结果表明,钙元素摄入严重不足,仅占供给量(RDA)的40．56％;其次是维生素A、胡萝卜素、核黄素摄入不足,分别为供给量(RDA)的62．32％、51．97％、54．17％;脂肪偏高,碳水化合物偏低。提示该校学生营养素摄入不均衡,钙元素摄入量不足尤为突出,膳食结构需要改进。     

Serum vitamin D levels in office workers in a subtropical climate

Vitamin D is necessary to maintain healthy bones, and may prevent other chronic diseases. There is limited information regarding the vitamin D status of people living in climates with relatively high ambient ultraviolet radiation. We therefore aimed to determine serum 25(OH)D levels in a group of office-workers in subtropical Australia. We collected blood from 129 office workers in summer (n = 129) and 175 in winter (91 in both seasons). Serum 25(OH)D was estimated using a commercial chemiluminescent immunoassay and we asked participants to complete questionnaires about sun exposure and diet for the month prior to blood collection. Summer and winter mean serum 25(OH)D was 74 (95% CI 70-77) nmol L(-1) and 54 (95% CI 51-57) nmol L(-1), respectively. In summer, 14% of participants were classed as "insufficient," compared with 51% in winter. High 25(OH)D levels in summer were associated with time spent outdoors in nonpeak UV periods, while in winter high levels were associated with intake of vitamin D from food or supplements. The high prevalence of vitamin D insufficiency observed in this population highlights the need for further examination of the relation between sunlight and vitamin D production to enable more accurate sun exposure recommendations.     

Status of methodology for the determination of fat-soluble vitamins in foods, dietary supplements, and vitamin premixes

Fat-soluble vitamins (FSVs) include vitamin A, carotenoids, vitamins D, E, and K. New legislation is being introduced in many countries to reinforce regulatory compliance of declared concentrations of vitamins and other micronutrients in food products and dietary supplements. The levels of FSVs are likely to be more closely scrutinized due to their potential health risks associated with overdosing, in particular of vitamin D. However, a proviso of stricter regulatory compliance is that analytical methods must be fit-for-purpose, providing adequate accuracy and precision. Official methods have been published by organizations such as AOAC INTERNATIONAL, European Committee for Standardization, International Dairy Federation, U.S. Pharmacopeia, and International Organization for Standardization. The methods available for foods, dietary supplements, and vitamin premixes are evaluated in this review. In general, these methods show adequate precision for regulatory compliance; however, the field of application has not often been evaluated for a sufficiently large range of food matrixes. Gaps have been noted in the range of published official procedures, particularly for carotenoids and vitamin premixes. The potential of some recent developments in sample preparation and chromatographic techniques were evaluated to provide improved procedures for FSV analysis the future.     

Antioxidant and Anti-Inflammatory Potential of Polyphenols Contained in Mediterranean Diet in Obesity: Molecular Mechanisms

Nutrition transition can be defined as shifts in food habits, and it is characterized by high-fat (chiefly saturated animal fat), hypercaloric and salty food consumption at the expense of dietary fibers, minerals and vitamins. Western dietary patterns serve as a model for studying the impact of nutrition transition on civilization diseases, such as obesity, which is commonly associated with oxidative stress and inflammation. In fact, reactive oxygen species (ROS) overproduction can be associated with nuclear factor-κB (NF-κB)-mediated inflammation in obesity. NF-κB regulates gene expression of several oxidant-responsive adipokines including tumor necrosis factor-α (TNF-α). Moreover, AMP-activated protein kinase (AMPK), which plays a pivotal role in energy homeostasis and in modulation of metabolic inflammation, can be downregulated by IκB kinase (IKK)-dependent TNF-α activation. On the other hand, adherence to a Mediterranean-style diet is highly encouraged because of its healthy dietary pattern, which includes antioxidant nutraceuticals such as polyphenols. Indeed, hydroxycinnamic derivatives, quercetin, resveratrol, oleuropein and hydroxytyrosol, which are well known for their antioxidant and anti-inflammatory activities, exert anti-obesity proprieties. In this review, we highlight the impact of the most common polyphenols from Mediterranean foods on molecular mechanisms that mediate obesity-related oxidative stress and inflammation. Hence, we discuss the effects of these polyphenols on a number of signaling pathways. We note that Mediterranean diet (MedDiet) dietary polyphenols can de-regulate nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) and NF-κB-mediated oxidative stress, and metabolic inflammation. MedDiet polyphenols are also effective in upregulating downstream effectors of several proteins, chiefly AMPK.     

Effects of vitamin d treatment on skeletal muscle histology and ultrastructural changes in a rodent model

Vitamin D is well known for its role in maintaining calcium and phosphorus homeostasis and in promoting bone mineralization; however, more of its pleiotropic effects have been described recently. The aim of the present investigation was to study the effect of vitamin D treatment on skeletal muscles changes under different dietary conditions using an animal model. Four groups of C57BL/6J mice (n = 11 each) were maintained on either low fat diet (LFD) or high fat diet ??(HFD) with and without 1α,25-dihydroxyvitamin D3 (calcitriol) for 16 weeks. Animal weigh was recorded at baseline and then regular intervals, and at the end of the study, skeletal muscle tissues were harvested for the evaluation of the histopathological and ultrastructural changes. When control C57BL/6J mice were fed high-fat diet for 12 weeks, body weight gain was significantly increased compared with mice fed a LFD. (30.2% vs. 8.4%, p < 0.01). There was a significant gradual decrease in the weight of HFD fed mice that were treated with vitamin D as compared with a steady increase in the weights of controls (6.8% vs. 28.7%, p < 0.01). While the LFD group showed some ultrastructural changes, HDF fed on mice showed great muscle structural abnormalities. The whole sarcosome along with its membrane and cristae were severely damaged with scattered myocytes in HFD group. Furthermore, the mitochondria appeared weak and were on the verge of degenerations. The bands were diminished with loss of connections among myofibrils. These changes were attenuated in the HFD group treated with vitamin D with tissues have regained their normal structural appearance. The current findings indicate an important effect of vitamin D on skeletal muscle histology under HFD conditions.     

The Role of Vitamin C,Vitamin D,and Selenium in Immune System against COVID-19

Low levels of micronutrients have been associated with adverse clinical outcomes during viral infections. Therefore, to maximize the nutritional defense against infections, a daily allowance of vitamins and trace elements for malnourished patients at risk of or diagnosed with coronavirus disease 2019 (COVID-19) may be beneficial. Recent studies on COVID-19 patients have shown that vitamin D and selenium deficiencies are evident in patients with acute respiratory tract infections. Vitamin D improves the physical barrier against viruses and stimulates the production of antimicrobial peptides. It may prevent cytokine storms by decreasing the production of inflammatory cytokines. Selenium enhances the function of cytotoxic effector cells. Furthermore, selenium is important for maintaining T cell maturation and functions, as well as for T cell-dependent antibody production. Vitamin C is considered an antiviral agent as it increases immunity. Administration of vitamin C increased the survival rate of COVID-19 patients by attenuating excessive activation of the immune response. Vitamin C increases antiviral cytokines and free radical formation, decreasing viral yield. It also attenuates excessive inflammatory responses and hyperactivation of immune cells. In this mini-review, the roles of vitamin C, vitamin D, and selenium in the immune system are discussed in relation to COVID-19.     

Comprehensive high-performance liquid chromatographic method for the measurements of lipophilic antioxidants in human plasma

Owing to the increasing interest in the health effects of antioxidant micronutrients on chronic diseases, a robust and rapid HPLC method for simultaneous measurement of coenzyme Q₁₀ (ubiquinone and ubiquinol), vitamin A (all-trans-retinol), vitamin E (tocopherols and tocotrienols) and carotenoids (lutein, zeaxanthin, β-cryptoxanthin, lycopene and β-carotene) was developed. Sample preparation and analytical conditions that would affect solubility and stability of these antioxidants were investigated and optimized. The mobile phase used was made up of acetonitrile, methanol, ethanol and tert-butanol without corrosive additives such as ammonium perchlorate and perchloric acid. Our results show that using two C₁₈ columns coupled with photodiode array, fluorescence and electrochemical detection, a comprehensive spectrum of 16 lipid-soluble antioxidants in 30 μL of plasma could be separated and quantified within 30 min. The chromatographic run time was about 3-fold faster and the sample size was about 5-fold smaller than when assays were performed separately using existing methods. The present method will be useful for dietary habit studies and for antioxidant status investigations.     

籽粒铁、锌营养与人体健康研究进展

综述了解决人体微量元素缺乏的几种途径,即药物防治、饮食多样化、食品防御工程和生物防御工程。认为生物强化工程即通过育种途径来增加籽粒中微量元素含量以其节省费用、持久性、广泛性和安全性之优点而更具发展潜力。同时,总结了国内外关于籽粒微量元素营养,尤其是铁和锌营养的最新研究进展,并提出了农业工作者在该领域的切入点。     

Analytical approaches to determination of total choline in foods and dietary supplements

Choline is a quaternary amine that is synthesized in the body or consumed through the diet. Choline is critical for cell membrane structure and function and in synthesis of the neurotransmitter acetylcholine. Although the human body produces this micronutrient, dietary supplementation of choline is necessary for good health. The major challenge in the analysis of choline in foods and dietary supplements is in the extraction and/or hydrolysis approach. In many products, choline is present as choline esters, which can be quantitated individually or treated with acid, base, or enzymes in order to release choline ions for analysis. A critical review of approaches based on extraction and quantitation of each choline ester as well as hydrolysis-based methods for determination of total choline in foods and dietary supplements is presented.     

广东省高校大学生膳食调查及营养配餐推荐

本调查报告采用问卷法了解广东主要高校大学生一周内熟食进食量及用餐情况，计算出每人每日热量和各种营养素的摄人量，采用Microsoft Excel软件进行数据处理和统计分析，并用中国营养学会制订的DRIs(膳食营养素参考摄人量)和中国居民膳食指南及平衡膳食宝塔进行比较分析，且通过微量元素检测对结果进行了验证，最后提供了为期一周的营养配餐作为膳食参考。主要调查结果如下：男女生的蛋白质、尼克酸、维生素C、维生素E、碘和男生锰的摄入量已经满足人体需要。男生铁和锰的摄入量基本满足需要。男女生的能量、脂肪、膳食纤维、维生素A、硫胺素、核黄素、钙、锌的摄人量都不足，且女生铁的摄人量同样不足。男女生一日三餐热量分配结构十分不平衡，早餐的热量摄入均偏低，膳食结构也不合理。在分析广东省大学生膳食状况的基础上，推出五套营养配餐方案供高校膳食部门和大学生参考选用。     

Tea Seed Kaempferol Triglycoside Attenuates LPS-Induced Systemic Inflammation and Ameliorates Cognitive Impairments in a Mouse Model

(1) Background: The current research intended to obtain functional compounds from agricultural by-products. A functional tea seed flavonoid, kaempferol-3-O-[2-O-β-d-xylopyranosyl-6-O-α-L-rhanmopyranosyl]-β-d-glucopyranoside (KXRG), was isolated from tea seed dregs. We further determined its chemical structure and evaluated the protective effects of KXRG against local and systemic inflammation in vivo; (2) Methods: First, cytotoxicity and proinflammatory cytokine release were examined in a cell-culture system. The biological activities of KXRG were investigated in a mouse model of ear edema, and from inflammatory damage to organs as demonstrated by histologic examination, in addition to brain function evaluation using the Y-maze test. Serum biochemical analysis and western blotting were utilized to explore the related cellular factors; (3) Results: KXRG inhibited IL-6 in RAW264.7 cells at a non-toxic concentration. Further experiments confirmed that KXRG exerted a stronger effect than indomethacin in terms of the prevention of 12-O-tetradecanoylphorbol acetate (TPA)-induced ear inflammation in a mouse model. KXRG feeding significantly prevented LPS-induced small intestine, liver, and kidney inflammatory damage, as demonstrated by histologic examination. KXRG also significantly improved LPS-induced cognitive impairments. Serum biochemical analysis showed that KXRG elevated antioxidant capacity and reduced levels of proinflammatory cytokines. Western blotting revealed that KXRG reduced the COX-2 expression induced by LPS in mouse tissues; (4) Conclusions: KXRG can be purified from agricultural waste, and hence it is inexpensive, with large amounts of raw materials available. Thus, KXRG has strong potential for further development as a wide-use anti-systemic inflammation drug to prevent human disease.