Zinc nutrition and dietary zinc supplements

Dietary zinc supplements: beneficial health effects and application in food, medicine and animals

Zinc, a crucial trace element is vital for the growth and development of humans. It is frequently described as 'the flower of life' and 'the source of intelligence'. Zinc supplements play a pivotal role in addressing zinc deficiency by serving as a vital source of this essential micronutrients, effectively replenishing depleted zinc levels in the body. In this paper, we first described the biological behavior of zinc in the human body and briefly described the physiological phenomena associated with zinc levels. The benefits and drawbacks of various zinc supplement forms are then discussed, with emphasis on the most recent zinc supplement formulations. Finally, the application of zinc supplements in food, medicine, and animal husbandry is further summarized. © 2024 Society of Chemical Industry.

Mineral-element-chelating activity of food-derived peptides: influencing factors and enhancement strategies

Mineral elements including calcium, iron, and zinc play crucial roles in human health. Their deficiency causes public health risk globally. Commercial mineral supplements have limitations; therefore, alternatives with better solubility, bioavailability, and safety are needed. Chelates of food-derived peptides and mineral elements exhibit advantages in terms of stability, absorption rate, and safety. However, low binding efficiency limits their application. Extensive studies have focused on understanding and enhancing the chelating activity of food-derived peptides with mineral elements. This includes obtaining peptides with high chelating activity, elucidating interaction mechanisms, optimizing chelation conditions, and developing techniques to enhance the chelating activity. This review provides a comprehensive theoretical basis for the development and utilization of food-derived peptide-mineral element chelates in the food industry. Efforts to address the challenge of low binding rates between peptides and mineral elements have yielded promising results. Optimization of peptide sources, enzymatic hydrolysis processes, and purification schemes have helped in obtaining peptides with high chelating activity. The understanding of interaction mechanisms has been enhanced through advanced separation techniques and molecular simulation calculations. Optimizing chelation process conditions, including pH and temperature, can help in achieving high binding rates. Methods including phosphorylation modification and ultrasonic treatment can enhance the chelating activity.

The roles of essential trace elements in T cell biology

T cells are crucial for adaptive immunity to regulate proper immune response and immune homeostasis. T cell development occurs in the thymus and mainly differentiates into CD4+ and CD8+ T cell subsets. Upon stimulation, naive T cells differentiate into distinct CD4+ helper and CD8+ cytotoxic T cells, which mediate immunity homeostasis and defend against pathogens or tumours. Trace elements are minimal yet essential components of human body that cannot be overlooked, and they participate in enzyme activation, DNA synthesis, antioxidant defence, hormone production, etc. Moreover, trace elements are particularly involved in immune regulations. Here, we have summarized the roles of eight essential trace elements (iron, zinc, selenium, copper, iodine, chromium, molybdenum, cobalt) in T cell development, activation and differentiation, and immune response, which provides significant insights into developing novel approaches to modulate immunoregulation and immunotherapy.

Highly-Efficient Gallium-Interference Tumor Therapy Mediated by Gallium-Enriched Prussian Blue Nanomedicine

Prussian blue (PB)-based nanomedicines constructed from metal ion coordination remain restricted due to their limited therapeutic properties, and their manifold evaluation complexity still needs to be unraveled. Owing to the high similarities of its ionic form to iron (Fe) and the resulting cellular homeostasis disruption performance, physiologically unstable and low-toxicity gallium (Ga) has garnered considerable attention clinically as an anti-carcinogen. Herein, Ga-based nanoparticles (NPs) with diverse Ga contents are fabricated in one step using PB with abundant Fe sites as a substrate for Ga substitution, which aims to overcome the deficiencies of both and develop an effective nanomedicine. A systematic comparison of their physicochemical properties effectively reveals the saturated Ga introduction state during the synthesis process, further identifying the most Ga-enriched PB NPs with a substitution content of >50% as a nanomedicine for subsequent exploration. It is verified that the Ga interference mechanisms mediated by the most Ga-enriched PB NPs are implicated in metabolic disorders, ionic homeostasis disruption, cellular structure dysfunction, apoptosis, autophagy, and target activation of the mammalian target of the rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) pathways. This study provides significant guidance on exploiting clinically approved agents for Ga interference and lays the foundation for the next generation of PB-based theranostic agents.

Cellular zinc metabolism and zinc signaling: from biological functions to diseases and therapeutic targets

Zinc metabolism at the cellular level is critical for many biological processes in the body. A key observation is the disruption of cellular homeostasis, often coinciding with disease progression. As an essential factor in maintaining cellular equilibrium, cellular zinc has been increasingly spotlighted in the context of disease development. Extensive research suggests zinc's involvement in promoting malignancy and invasion in cancer cells, despite its low tissue concentration. This has led to a growing body of literature investigating zinc's cellular metabolism, particularly the functions of zinc transporters and storage mechanisms during cancer progression. Zinc transportation is under the control of two major transporter families: SLC30 (ZnT) for the excretion of zinc and SLC39 (ZIP) for the zinc intake. Additionally, the storage of this essential element is predominantly mediated by metallothioneins (MTs). This review consolidates knowledge on the critical functions of cellular zinc signaling and underscores potential molecular pathways linking zinc metabolism to disease progression, with a special focus on cancer. We also compile a summary of clinical trials involving zinc ions. Given the main localization of zinc transporters at the cell membrane, the potential for targeted therapies, including small molecules and monoclonal antibodies, offers promising avenues for future exploration.

Ratiometric Detection of Zn2+ Using DNAzyme-Based Bioluminescence Resonance Energy Transfer Sensors

While fluorescent sensors have been developed for monitoring metal ions in health and diseases, they are limited by the requirement of an excitation light source that can lead to photobleaching and a high autofluorescence background. To address these issues, bioluminescence resonance energy transfer (BRET)-based protein or small molecule sensors have been developed; however, most of them are not highly selective nor generalizable to different metal ions. Taking advantage of the high selectivity and generalizability of DNAzymes, we report herein DNAzyme-based ratiometric sensors for Zn2+ based on BRET. The 8-17 DNAzyme was labeled with luciferase and Cy3. The proximity between luciferase and Cy3 permiQed BRET when coelenterazine, the substrate for luciferase, was introduced. Adding samples containing Zn2+ resulted in a cleavage of the substrate strand, causing dehybridization of the DNAzyme construct, thus increasing the distance between Cy3 and luciferase and changing the BRET signals. Using these sensors, we detected Zn2+ in serum samples and achieved Zn2+ detection with a smartphone camera. Moreover, since the BRET pair is not the component that determines the selectivity of the sensors, this sensing platform has the potential to be adapted for the detection of other metal ions with other metal-dependent DNAzymes.

Development, characterization and in vivo zinc absorption capacity of a novel soy meal hydrolysate-zinc complexes

Background

Zinc is an essential trace element for the human body. Recently, a novel Zn-binding peptide, Lys-Tyr-Lys-Arg-Gln-Arg-Trp (PP), was purified and identified from soy protein hydrolysates with high Zn-binding capacity (83.21 ± 2.65%) by our previous study. The preparation of soy meal hydrolysates (SMHs)-Zn complexes is convenient and low-cost, while PP (Lys-Tyr-Lys-Arg-Gln-Arg-Trp)-Zn complexes have a higher coordination rate but a relatively high cost. The aim of this study was to investigate the effect of soy meal hydrolysates (SMHs)-Zn complexes on zinc absorption in mice model, and synthetic soy peptide (PP)-Zn complexes with high Zn-binding capacity were used as control. Firstly, SMHs were prepared by enzymolysis, and the PP (Lys-Tyr-Lys-Arg-Gln-Arg-Trp) were synthesized based on previous studies. The binding mechanism of soy hydrolysates and zinc was analyzed by spectral analysis. Furthermore, the cytotoxicity of the SMHs-Zn complexes was also studied using the CCK-8 method. The effect of zinc absorption was evaluated based on Zn content, total protein and albumin content, relevant enzyme system, and the PeT1 and ZnT1 mRNA expression levels.

Result

The result showed that zinc was bound with carboxyl oxygen and amino nitrogen atoms on SMHs, with hydrophobic and electrostatic interactions as auxiliary stabilizing forces. SMHs-Zn were proved to have great solubility and a small particle size at different pH values, and it showed a beneficial effect on Caco-2 cells growth. Moreover, it was proved that SMHs-Zn and PP-Zn could increase the levels of zinc and the activity of Zn-related enzymes in mice. SMHs-Zn possessed higher PepT1 and ZnT1 mRNA expression levels than PP-Zn in the small intestine.

Conclusion

SMHs-Zn with a lower Zn-binding capacity had similar effects on zinc absorption in mice as PP-Zn, suggesting that the bioavailability of peptide-zinc complexes in mice was not completely dependent on their Zn-binding capacity, but may also be related to the amino acid composition.

Metal-binding peptides and their potential to enhance the absorption and bioavailability of minerals

Minerals including calcium, iron, zinc, magnesium, and copper have several human nutritional functions due to their metabolic activities. Body tissues require sufficient levels of a variety of micronutrients to maintain their health. To achieve these micronutrient needs, dietary consumption must be adequate. Dietary proteins may regulate the biological functions of the body in addition to acting as nutrients. Some peptides encoded in the native protein sequences are primarily responsible for the absorption and bioavailability of minerals in physiological functions. Metal-binding peptides (MBPs) were discovered as potential agents for mineral supplements. Nevertheless, sufficient studies on how MBPs affect the biological functions of minerals are lacking. The hypothesis is that the absorption and bioavailability of minerals are significantly influenced by peptides, and these properties are further enhanced by the configuration and attribute of the metal-peptide complex. In this review, the production of MBPs is discussed using various key parameters such as the protein sources and amino acid residues, enzymatic hydrolysis, purification, sequencing and synthesis and in silico analysis of MBPs. The mechanisms of metal-peptide complexes as functional food ingredients are elucidated, including metal-peptide ratio, precursors and ligands, complexation reaction, absorbability and bioavailability. Finally, the characteristics and application of different metal-peptide complexes are also described.

Navigating zinc-involved nanomedicine in oncotherapy

Zinc (Zn), extolled as "the flower of life" in modern medicine, has been extensively highlighted with its physiological functions to maintain growth, development, and metabolism homeostasis. Driven by the substantial advancement of nanotechnology and oncology, Zn-involved nanomedicines integrating the intrinsic bioactivity of Zn species and the physiochemical attributes of Zn-composed nanosystems have blazed a highly efficient and relatively biosafe antineoplastic path. In this review, we aim to highlight and discuss the recent representative modalities of emerging Zn-involved oncology nanomedicine, mainly emphasizing the rational design, biological effect and biosafety, and therapeutic strategies. In addition, we provide the underlying critical obstacles and future perspectives of Zn-involved oncology nanomedicines, primarily focusing on the chances and challenges of clinical translation. Furthermore, we hope the review can give rise to opportunities within oncology nanomedicine and other biomedical fields, promoting the prosperity and progress of the "Zincic Age".

Effects of Dietary Zinc Deficiency on Skin Breaking Strength and Fatty Acid Composition in Broiler Chickens and Pekin Ducks

This study is aimed at investigating the effect of dietary zinc deficiency (ZnD) on skin breaking strength and skin chemical and fatty acid composition in broiler chickens and Pekin ducks. A total of 200 1-day-old male broiler chickens and 200 1-day-old male ducklings were used in a 2 × 2 factorial design and randomly allocated to 4 treatments with 10 replicated cages of 10 birds per cage. Diets containing zinc at 84.77 mg/kg and 20.42 mg/kg were regarded as the control diet and zinc-deficient diet, respectively. The results showed the following: (1) dietary ZnD decreased (P < 0.05) the breast skin weight (day 21), breast skin index (day 21), skin fat content (day 7), and skin Zn content (days 7, 14, and 21) of ducks, but only increased (P < 0.05) the skin fat content of broiler chickens at 7 days of age; ducks had a higher (P < 0.05) breast skin weight, breast skin index, and skin breaking strength as well as a lower skin fat content (days 7 and 14) than those in broiler chickens. (2) Dietary ZnD decreased the content of myristic acid (day 21) and increased the content of oleic acid (day 7) content in the skin of ducks and increased the palmitic acid (day 7) content in the skin of broiler chickens (P < 0.05) and increased the MUFA (day 7) content in the skin and the atherogenic index (day 21) in ducks. The contents of myristic acid (day 21), stearic acid (day 21), and oleic acid (days 7, 14, and 21) in the skin of broiler chickens were lower (P < 0.05) than those in ducks of the same age. In conclusion, using skin weight, skin index and skin MUFA content as criteria, the results indicated that meat ducks were more sensitive to dietary ZnD than broiler chickens. Using skin fat content as criterion, the results indicated that broiler chickens were more sensitive to dietary ZnD than meat ducks.

Restoration of the GTPase activity and cellular interactions of Gαo mutants by Zn2+ in GNAO1 encephalopathy models

De novo point mutations in GNAO1, gene encoding the major neuronal G protein Gα_o, have recently emerged in patients with pediatric encephalopathy having motor, developmental, and epileptic dysfunctions. Half of clinical cases affect codons Gly²⁰³, Arg²⁰⁹, or Glu²⁴⁶; we show that these mutations accelerate GTP uptake and inactivate GTP hydrolysis through displacement Gln²⁰⁵ critical for GTP hydrolysis, resulting in constitutive GTP binding by Gα_o. However, the mutants fail to adopt the activated conformation and display aberrant interactions with signaling partners. Through high-throughput screening of approved drugs, we identify zinc pyrithione and Zn²⁺ as agents restoring active conformation, GTPase activity, and cellular interactions of the encephalopathy mutants, with negligible effects on wild-type Gα_o. We describe a Drosophila model of GNAO1 encephalopathy where dietary zinc restores the motor function and longevity of the mutant flies. Zinc supplements are approved for diverse human neurological conditions. Our work provides insights into the molecular etiology of GNAO1 encephalopathy and defines a potential therapy for the patients.

An Edible and Nutritive Zinc-Ion Micro-supercapacitor in the Stomach with Ultrahigh Energy Density

Miniature energy storage devices simultaneously combining high energy output and bioavailability could greatly promote the practicability of green, safe, and nontoxic in vivo detection, such as for noninvasive monitoring or treatment in the gastrointestinal tract, which is still challenging. Herein, we report ingestible and nutritive zinc-ion-based hybrid micro-supercapacitors (ZMSCs) consisting of an edible active carbon microcathode and zinc microanode, which can be inserted into a standard-sized capsule and ingested in a pig stomach. With features including flexibility, light weight, and shape adaptability, a single microdevice displays a high energy density of 215.1 μWh cm^-2, superior to that of state-of-the-art biocompatible SCs/MSCs and even traditional ZMSCs reported previously. It also delivers an areal capacitance of 605 mF cm^-2 and a high working voltage of 1.8 V, exceeding that of miniaturized commercial button batteries (1.55 V, RENATA 337). Comprehensive studies in vivo and in vitro demonstrate that the ZMSCs with high biocompatibility and safety not only power electronic equipment in the porcine stomach without a voltage booster but also act as a nutritional supplement of trace element zinc within the dose range, as well as the ability of potent antibacterial activity against bacterium Escherichia coli during the discharging process. This work provides an example for the design and fabrication of edible energy storage devices with high performance.

Replacing ZnSO4 with Zn-glycine in the diet of goat promotes the pancreatic function of the offspring

Zinc supplementation in the diet of goats affects pancreas development in offspring. However, the impact of maternal inorganic and organic zinc supplementation in offspring is poorly defined. In this study, 14 late-pregnant goats were assigned at random to the zinc sulfate group (ZnSO₄, n = 7) and the zinc-glycine chelate group (Zn-Gly, n = 7), respectively. Serum samples and pancreas tissue were collected from kids whose mothers were fed ZnSO₄ and Zn-Gly at the late pregnancy, respectively. Histologic examination showed no morphologic differences between the 2 groups. Pancreatic zinc content in kids tended to be increased when replacing ZnSO₄ with Zn-Gly. The serum insulin concentration was greater and glucagon less in the Zn-Gly group when compared to the ZnSO₄ group. The activities of lipase and chymotrypsin were enhanced when replacing ZnSO₄ with Zn-Gly. Proteomics results showed that 234 proteins were differentially expressed between the 2 groups, some of which were associated with the secretion of insulin, enzyme activity and signal transduction. The results suggested that supply of dietary Zn-Gly to goats during late pregnancy promoted pancreatic function in offspring compared with dietary ZnSO₄ supplementation. This provides new information about pancreatic function when supplementing different zinc sources in the diets of late pregnant goats.