Plant calcium content: ready to remodel

Interventions to improve calcium intake through foods in populations with low intake

Calcium intake remains inadequate in many low- and middle-income countries, especially in Africa and South Asia, where average intakes can be below 400 mg/day. Given the vital role of calcium in bone health, metabolism, and cell signaling, countries with low calcium intake may want to consider food-based approaches to improve calcium consumption and bioavailability within their population. This is especially true for those with low calcium intake who would benefit the most, including pregnant women (by reducing the risk of preeclampsia) and children (by reducing calcium-deficiency rickets). Specifically, some animal-source foods that are naturally high in bioavailable calcium and plant foods that can contribute to calcium intake could be promoted either through policies or educational materials. Some food processing techniques can improve the calcium content in food or increase calcium bioavailability. Staple-food fortification with calcium can also be a cost-effective method to increase intake with minimal behavior change required. Lastly, biofortification is currently being investigated to improve calcium content, either through genetic screening and breeding of high-calcium varieties or through the application of calcium-rich fertilizers. These mechanisms can be used alone or in combination based on the local context to improve calcium intake within a population.

Calcium Biofortification of Crops-Challenges and Projected Benefits

Despite Calcium (Ca) being an essential nutrient for humans, deficiency of Ca is becoming an ensuing public health problem worldwide. Breeding staple crops with higher Ca concentrations is a sustainable long-term strategy for alleviating Ca deficiency, and particular criteria for a successful breeding initiative need to be in place. This paper discusses current challenges and projected benefits of Ca-biofortified crops. The most important features of Ca nutrition in plants are presented along with explicit recommendations for additional exploration of this important issue. In order for Ca-biofortified crops to be successfully developed, tested, and effectively implemented in most vulnerable populations, further research is required.

Mineral Biofortification of Vegetables as a Tool to Improve Human Diet

Vegetables represent pillars of good nutrition since they provide important phytochemicals such as fiber, vitamins, antioxidants, as well as minerals. Biofortification proposes a promising strategy to increase the content of specific compounds. As minerals have important functionalities in the human metabolism, the possibility of enriching fresh consumed products, such as many vegetables, adopting specific agronomic approaches, has been considered. This review discusses the most recent findings on agronomic biofortification of vegetables, aimed at increasing in the edible portions the content of important minerals, such as calcium (Ca), magnesium (Mg), iodine (I), zinc (Zn), selenium (Se), iron (Fe), copper (Cu), and silicon (Si). The focus was on selenium and iodine biofortification thus far, while for the other mineral elements, aspects related to vegetable typology, genotypes, chemical form, and application protocols are far from being well defined. Even if agronomic fortification is considered an easy to apply technique, the approach is complex considering several interactions occurring at crop level, as well as the bioavailability of different minerals for the consumer. Considering the latter, only few studies examined in a broad approach both the definition of biofortification protocols and the quantification of bioavailable fraction of the element.

Culinary and herbal resources as nutritional supplements against malnutrition-associated immunity deficiency: the vegetarian review

Background

Malnutrition may be due to undernutrition and/or overnutrition and is responsible for morbidity and mortality. Fulfilling nutrition requirements of all human age groups is necessary for maintenance of health and quality of life. Nutritional supplements, or daily diet, must include a sufficient amount of macronutrient (carbohydrate, protein, and fat), micronutrients (vitamins and minerals), and nonessential dietary components such as fiber.

Main body

There is a bidirectional relationship that exists between nutrition, infection, and immunity; children are dying due to malnutrition that weakens their immunity and makes them more susceptible to pathogen attack. Culinary and herbal resources containing macro- and micronutrients are required to achieve nutritional deficiencies.

Conclusion

In this review, we have documented different culinary herbs that have been used as prime herbal nutritional source and these herbs might be helpful in malnutrition and boosting immunity. The review contains the description of nutritional levels and their distribution to different age group people. This review gives insight to herbal products that boost immunity to fight against infections by restoring micronutrients.

Mineral Content of the Pulp and Peel of Various Citrus Fruit Cultivars

The aim of the study was to compare the mineral content between the peel and the pulp of citrus fruits and to determine which citrus fruit, among orange (Citrus sinensis), pomelo (Citrus maxima), mandarin (Citrus reticulata Blanco), lemon (Citrus limon), key lime (Citrus aurantifolia), and red, yellow, or green grapefruit (Citrus paradisi), is the richest in minerals. The research material consisted of fresh citrus fruits belonging to the genus Citrus L in the family Rutaceae. The fruits were purchased at a supermarket at one time. To prepare laboratory samples, each fruit was cut in half, and one half was homogenized, treating the sample as a whole (peel + flesh), while the other half was peeled and the pulp (F) and peel (P) were homogenized separately. To determine the content of minerals (Na⁺, K⁺, Ca⁺², Mg⁺², Fe⁺², Zn⁺², Cu⁺², Mn⁺², and Se⁺²), the samples were mineralized and analyzed using an Analytik Jena PlasmaQuant PQ 9000 inductively coupled plasma optical emission spectrometer. The content of macro- and micronutrients in the peel of most of the fruits far exceeded their quantity in the pulp. Oranges and pomelos are the fruits richest in iron and copper, so they could be recommended in cases such as hemoglobin production disorders resulting from a deficiency of these elements. Oranges can additionally enrich the body with potassium, phosphorus, and manganese, while lime can be a source of calcium, zinc, sodium, and especially potassium. It should also be noted that all citrus fruits are a very valuable source of potassium, which is needed to ensure the water and electrolyte balance.

Phytochemical profiling, polyphenol composition, and antioxidant activity of the leaf extract from the medicinal halophyte Thespesia populnea reveal a potential source of bioactive compounds and nutraceuticals

The present study evaluated the phytochemical constituents, nutritional attributes, and the antioxidant capacity of the medicinal halophyte Thespesia populnea. The metabolite profiling by GC-QTOF-MS analysis identified 37 metabolites among which sucrose, malic acid, and turanose were the most abundant. A total of 18 polyphenols and 17 amino acids were identified by the HPLC-DAD analysis. The most abundant polyphenols in T. populnea were gallic acid, catechin, and myricetin. Other polyphenols like protocatechuic acid, epigallocatechin gallate, rosmarinic acid, ellagic acid, rutin, and naringenine were also detected in ample amounts. The leaf extract demonstrated higher antioxidant as well as lipid peroxidation inhibition activities. A correlation analysis revealed a positive correlation between the antioxidant capacity and the phenolic compounds viz. gallic acid, catechin, myricetin, quercetin, apigenin, cinnamic acid, and coumarin which indicates that these phenolic compounds are the main contributors of the antioxidant potential of T. populnea. The results of this study establish T. populnea as a potential source of nonconventional functional food. PRACTICAL APPLICATIONS: The data presented here indicate that T. populnea can be considered as a nonconventional functional food and potential source of energy, antioxidants, minerals, essential amino acids, and bioactive compounds in herbal formulations, food supplements, or nutraceuticals. The metabolites identified from this halophyte have pharmacological and nutraceutical potentials, suggesting T. populnea as an ideal candidate for application in the food and phytopharmaceutical industries to produce health-promoting products, functional foods, and herbal medicines.

CNGC2 Is a Ca2+ Influx Channel That Prevents Accumulation of Apoplastic Ca2+ in the Leaf

Ca²⁺ is absorbed by roots and transported upward through the xylem to the apoplastic space of the leaf, after which it is deposited into the leaf cell. In Arabidopsis (Arabidopsis thaliana), the tonoplast-localized Ca²⁺/H⁺ transporters CATION EXCHANGER1 (CAX1) and CAX3 sequester Ca²⁺ from the cytosol into the vacuole, but it is not known what transporter mediates the initial Ca²⁺ influx from the apoplast to the cytosol. Here, we report that Arabidopsis CYCLIC NUCLEOTIDE-GATED CHANNEL2 (CNGC2) encodes a protein with Ca²⁺ influx channel activity and is expressed in the leaf areas surrounding the free endings of minor veins, which is the primary site for Ca²⁺ unloading from the vasculature and influx into leaf cells. Under hydroponic growth conditions, with 0.1 mm Ca²⁺, both Arabidopsis cngc2 and cax1cax3 loss-of-function mutants grew normally. Increasing the Ca²⁺ concentration to 10 mm induced H₂O₂ accumulation, cell death, and leaf senescence and partially suppressed the hypersensitive response to avirulent pathogens in the mutants but not in the wild type. In vivo apoplastic Ca²⁺ overaccumulation was found in the leaves of cngc2 and cax1cax3 but not the wild type under the 10 mm Ca²⁺ condition, as monitored by Oregon Green BAPTA 488 5N, a low-affinity and membrane-impermeable Ca²⁺ probe. Our results indicate that CNGC2 likely has no direct roles in leaf development or the hypersensitive response but, instead, that CNGC2 could mediate Ca²⁺ influx into leaf cells. Finally, the in vivo extracellular Ca²⁺ imaging method developed in this study provides a new tool for investigating Ca²⁺ dynamics in plant cells.

CAX-ing a wide net: Cation/H(+) transporters in metal remediation and abiotic stress signalling

Cation/proton exchangers (CAXs) are a class of secondary energised ion transporter that are being implicated in an increasing range of cellular and physiological functions. CAXs are primarily Ca(2+) efflux transporters that mediate the sequestration of Ca(2+) from the cytosol, usually into the vacuole. Some CAX isoforms have broad substrate specificity, providing the ability to transport trace metal ions such as Mn(2+) and Cd(2+) , as well as Ca(2+) . In recent years, genomic analyses have begun to uncover the expansion of CAXs within the green lineage and their presence within non-plant species. Although there appears to be significant conservation in tertiary structure of CAX proteins, there is diversity in function of CAXs between species and individual isoforms. For example, in halophytic plants, CAXs have been recruited to play a role in salt tolerance, while in metal hyperaccumulator plants CAXs are implicated in cadmium transport and tolerance. CAX proteins are involved in various abiotic stress response pathways, in some cases as a modulator of cytosolic Ca(2+) signalling, but in some situations there is evidence of CAXs acting as a pH regulator. The metal transport and abiotic stress tolerance functions of CAXs make them attractive targets for biotechnology, whether to provide mineral nutrient biofortification or toxic metal bioremediation. The study of non-plant CAXs may also provide insight into both conserved and novel transport mechanisms and functions.

Calcium biofortification and bioaccessibility in soilless "baby leaf" vegetable production

Calcium is an essential nutrient for human health, because it is a structural component and takes part in a variety of biological processes. The aim of this study was to increase Ca content of baby leaf vegetables (BLV: basil, mizuna, tatsoi and endive), as fresh-cut products. For the production of biofortified BLV, a floating system with two level of Ca (100 and 200mgL(-1)) in the nutrient solution was used. In addition, the assessment of bioaccessibility of Ca, by in vitro digestion process, was performed. In all vegetables, the Ca biofortification (200mgL(-1)) caused a significant Ca enrichment (9.5% on average) without affecting vegetables growth, oxalate contents and marketable quality. Calcium bioaccessibility ranged from 25% (basil) to 40% (endive) but the biofortified vegetables showed more bioaccessible Ca. These results underline the possibility to obtain Ca biofortified BLV by using agronomic approaches.