Article

Absorbability of Calcium from Brassica Vegetables: Broccoli, Bok Choy, and Kale

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Abstract

Absorption of calcium from three intrinsically labeled Brussica sp. vegetables was measured in 15 normal women in a three-way randomized design. The test load of calcium was about 83 mg for each source. Fractional calcium absorption from broccoli averaged 0.478 ± 0.089, from bok choy stems, 0.519 ± 0.089, from bok choy leaves, 0.520 ± 0.074, and from kale 0.527 ± 0.091. These differences were both absolutely small and statistically insignificant. Mean absorbability of milk calcium ingested at the same load has been previously shown to be 0.463 ± .095. This value is slightly but significantly lower than the average value for the Brassica sources combined (0.514 ± 0.090). Thus, Brussicu vegetable sources exhibit excellent calcium bioavailability.

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... Interestingly, all these Brassica vegetables exhibit excellent calcium bioavailability. 105 Cabbage leaf (B. oleracea var. ...
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Brassicaceae plants are one of the most popular vegetables consumed all over the world and considered to be a good source of bioactive phytochemicals. Additionally, Brassica species and varieties are increasingly becoming a research model in plant science, as a consequence of the importance of their primary and secondary metabolites. Plant interaction with environmental stress factors including animals and insects herbivory, pathogens, metal ions, light, among others, is known to lead to the activation of various defense mechanisms resulting in a qualitative and/or quantitative change in plant metabolite production. Pre-harvest and/or post-harvest conditions are also known to affect this, since plants produce signaling molecules (e.g. salicylic acid, jasmonic acid, etc.) that cause a direct or indirect activation of metabolic pathways. That ultimately affects the production of phytochemicals, such as carbohydrates (sucrose and glucose), amino acids, phenolics (phenylpropanoids and flavonoids) and glucosinolates. These phytochemicals have diverse applications due to their antimicrobial, antioxidant and anti-carcinogenic properties, but on the other hand these compounds or their breakdown products can act as anti-nutritional factors in diet. In this review we report a wide range of the stress-induced metabolic responses in the Brassica plants commonly used for human consumption.
... Only two plant compo- nents, oxalate and phytate, have so far been regarded as the main complexing agents interfering with calcium absorption from beans ( Weaver et al., 1993;Heaney et al., 1991). Some studies have shown that calcium absorption was greater from low-oxalate food, such as kale, than from high-oxalate food, such as spinach or broccoli (Weaver et al., 1987;Heaney and Weaver, 1990;Heaney et al., 1993). Phytate has also been shown to interfere with the absorption of calcium ( Lonnerdal et al., 1989;Heaney et al., 1991), and calcium itself increases the severity of phytate impact by forming insoluble complexes with other minerals ( Ellis et al., 1987;Hallberg et al., 1991). ...
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Calcium potential availability from mottled and white bean was studied by using an in vitro model which simulates the conditions existing in the small intestine and the fermentation process in the colon. Beans contained high amounts of calcium which distribution in the seed varied greatly (hull 70%, cotyledon 30%). The percentage of calcium dialysability in both bean varieties was in the range of 14%. Dehulling greatly improved calcium dialysability; when compared to whole seed, increases of up to 97% (p<0.01) were found. Calcium dialysability from the hull was very low (4–8%). Dialysable calcium and soluble calcium were not affected by cooking. Results indicated that phytate was not the main inhibitor of calcium dialysability from beans. The overall calcium dialysability from beans was mainly influenced by the calcium status in the hull. Calcium released from retentate (from 24 to 72%), during in vitro fermentation experiments indicated a substantial degradation of the undialysable High Molecular Weight (HMW) calcium complexes within the 14 h of the fermentation process.
... broccoli (Brassica oleracea, Italica Group), have relatively high Ca concentrations and low levels of constituents that render Ca unavailable. Heaney et al. (1993) found bioavailability of Ca in these cruciferous vegetables to be equal (≈30%) to that of milk. ...
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Broccoli (Brassica oleracea L., Italica Group) is a good vegetable source of Ca and Mg, two critical minerals in human nutrition. Studies have shown that bioavailability of Ca from broccoli is comparable to that from milk. Thus, broccoli is an important alternative source of Ca in segments of the population that consume limited amounts of dairy products. Essentially nothing is known about the genetic influence on variation in Ca or Mg concentration of broccoli heads. Thus, the goal of this research was to examine variation in Ca, and also Mg concentrations, in a collection of USDA inbreds and commercial F1 hybrids. In 1996 and 1997 field studies, significant differences among inbred entries and among hybrid entries were observed for Ca and Mg concentrations of broccoli heads. With hybrids and inbreds, mean head Ca concentrations were ≃3.0 mg · g-1 dry weight (DW), and entries with lowest and highest Ca concentrations differed >2-fold. Mean Mg concentrations of hybrid heads was 2.3 mg · g-1 DW (range 1.8 to 2.6) and 2.8 mg · g-1 DW (range 2.2 to 3.7) in 1996 and 1997, respectively. Inbred lines had mean head Mg concentrations of 2.0 and 2.6 mg · g-1 DW in the two respective years and ranges in concentration were similar as for hybrids. Analysis of variance indicated significant environment and entry by environment effects for Ca and Mg concentrations of hybrids. With inbreds, a significant entry by environment effect for Ca concentration and environment effect for Mg concentration was also observed. Significant environment and entry by environment effects indicate that the environmental influence on phenotypic expression of Ca and Mg concentrations may complicate genetic improvement of head mineral concentration.
... Plants, therefore, can be looked upon as a cheap and convenient alternative source of dietary Ca. Some plants like carrot and broccoli exhibit Ca absorbability equal to or better than in milk, so plants could be a good alternative source of Ca (Heaney et al., 1993). Major staple crops however contain low levels of Ca and attempts to biofortify crops with greater amount of Ca had mixed results (Hirschi, 2009). ...
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Calcium (Ca) is an essential mineral for proper growth and development of plants as well as animals. In plants including cereals, calcium is deposited in seed during its development which is mediated by specialized Ca transporters. Common cereal seeds contain very low amounts of Ca while the finger millet (Eleusine coracana) contains exceptionally high amounts of Ca in seed. In order to understand the role of Ca transporters in grain Ca accumulation, developing seed transcriptome of two finger millet genotypes (GP-1, low Ca and GP-45 high Ca) differing in seed Ca content was sequenced using Illumina paired-end sequencing technology and members of Ca transporter gene family were identified. Out of 109,218 and 120,130 contigs, 86 and 81 contigs encoding Ca transporters were identified in GP-1 and GP-45, respectively. After removal of redundant sequences, a total of 19 sequences were confirmed as Ca transporter genes, which includes 11 Ca2 + ATPases, 07 Ca2 +/cation exchangers and 01 Ca2 + channel. The differential expressions of all genes were analyzed from transcriptome data and it was observed that 9 and 3 genes were highly expressed in GP-45 and GP-1 genotypes respectively. Validation of transcriptome expression data of selected Ca transporter genes was performed on different stages of developing spikes of both genotypes grown under different concentrations of exogenous Ca. In both genotypes, significant correlation was observed between the expression of these genes, especially EcCaX3, and on the amount of Ca accumulated in seed. The positive correlation of seed mass with the amount of Ca concentration was also observed. The efficient Ca transport property and responsiveness of EcCAX3 towards exogenous Ca could be utilized in future biofortification program.
... Plants, therefore, can be looked upon as a cheap and convenient alternative source of dietary Ca. Some plants like carrot and broccoli exhibit Ca absorbability equal to or better than in milk, so plants could be a good alternative source of Ca (Heaney et al., 1993). Major staple crops however contain low levels of Ca and attempts to biofortify crops with greater amount of Ca had mixed results (Hirschi, 2009). ...
... The antinutrients are also present in foods along with mineral content, however, high concentration of antinutrients may strongly reduce the mineral availability, especially that of calcium as it forms insoluble complexes called calcium oxalates which is unabsorbable. These can also affect the calcium availability from other foods when present in high amounts by rendering the negative effect on the absorption rate (Weaver et al., 1987;Heaney et al., 1993). Another group of inhibitors of minerals absorption is polyphenols and tannins. ...
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... At our knowledge, there is not literature reporting the putative beneficial effect of kale when manufactured in unusual way than salads or soups, two of the most diffused manner of eating this vegetable. Kale is rich of antioxidants, and represents a good source of minerals, like Fe, Mn, S, Ph; kale con- tains a noticeable amount of highly bioavailable Ca (about 9% of daily need) [8], as well as vitamins A, K and C. It has anticancer [9], anti-inflammatory [10] and hypocholesterolemic properties [11]; due to its high content of fibers and the absence of fat, kale has a very low content of calories. Thus, choice to use such raw matter for the production of these snacks can be very relevant from a functional viewpoint, taking also into account the high beneficial properties of kale on human health. ...
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Four types of kale-based snacks were investigated on the basis of polyphenol content and composition, glucosinolates amount, and antioxidant activity. The amount of polyphenols resulted to be higher than that of raw material, fresh kale (0.57 ± 0.03 mg GAE). The antioxidant activity turned out indeed very effective, resulting sufficient just from 0.72 mg to 2.1 mg to dishearten the activity of 1 ml DPPH to 50%. Glucosinolates present in kale-based snacks ranged from 1.17 mg/gr to 1.52 mg of sinigrin equivalent/gr. Polyphenol profile, obtained by UPLC-DAD analysis allowed us to identify gallic acid, chlorogenic acid, and catechin common in all samples. Other polyphenols, that is caffeic acid, p-coumaric acid, and ferulic acid, were found in almost all samples, almost all more abundant than fresh kale, representing a precious source of beneficial metabolites. Our results suggest that such snacks could represent an effective functional dietary supplement also if compared to fresh vegetable. Manufacturing of kale-based snacks does not negatively affect the beneficial effect of the raw material; indeed, such snacks could positively meet people’s expectation, mainly children and young, well known consumers of snacks, which, also in such manner, could be addressed towards a healthier dietary regime.
... In contrast, fractional calcium absorption is much higher in vegetables which are low in oxalate, e.g., kale, broccoli, bok choy, kai choy and choy sum (Table 5; [105,136]). In addition to oxalates, calcium absorption can also be inhibited by phytates, but to a lesser extent [147]. ...
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This article reviews physicochemical aspects of calcium absorption from foods. Notable differences are observed between different food products in relation to calcium absorption, which range from <10% to >50% of calcium in the foods. These differences can be related to the interactions of calcium with other food components in the food matrix, which are affected by various factors, including fermentation, and how these are affected by the conditions encountered in the gastrointestinal tract. Calcium absorption in the intestine requires calcium to be in an ionized form. The low pH in the stomach is critical for solubilization and ionization of calcium salts present in foods, although calcium oxalate complexes remain insoluble and thus poorly absorbable. In addition, the rate of gastric transit can strongly affect fractional absorption of calcium and a phased release of calcium into the intestine, resulting in higher absorption levels. Dairy products are the main natural sources of dietary calcium in many diets worldwide, which is attributable to their ability to provide high levels of absorbable calcium in a single serving. For calcium from other food products, lower levels of absorbable calcium can limit contributions to bodily calcium requirements.
... Values for the calcium content of foods were obtained primarily from the USDA Nutrient Database for Standard Reference (USDA/ARS, 2005). Values for the fractional absorption of calcium from specific foods were obtained from a variety of published scientific articles ( Heaney et al., 1993Heaney et al., , 2000Heaney et al., , 2005aWeaver et al., 1993Weaver et al., , 1997Weaver et al., , 2002). Since the fractional absorption of calcium is inversely related to the amount of calcium in a test food ( Heaney et al., 1990b), more than one value may have been published for a particular food. ...
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Since the bioavailability of calcium varies greatly among various types of foods, information merely listing the amounts of calcium in foods can be very misleading. Using published values for calcium fractional absorption, a simple two-criteria system is presented and used to assess foods as reasonable calcium sources. For a food to be a good calcium source, two criteria must be met: a standard serving must contain at least 30 mg of absorbable calcium, less than 418 kJ (100 kcal) of the food must provide 30 mg of absorbable calcium. Calcium-containing foods are divided here into good calcium sources (both criteria are met), potential calcium sources (only one criterion is met), and poor calcium sources. Good sources include most milk products, most types of tofu, some dark green leafy cabbage family vegetables, turnip greens and canned fish such as salmon and sardines that include bones. Potential calcium sources include ice cream and most green leafy vegetables. Poor calcium sources include cottage cheese, all beans, some types of tofu, almonds, and sesame seeds. Using this system to identify calcium-rich food sources avoids the misuse of nutrient data when foods are listed simply by their calcium content.
... The content of oxalates or fibers (phytate/dietary) seems to be associated with low calcium intake [106][107][108][109]. Indeed, high oxalates in spinach and rhubarb show 5% [110] and 9% [111] absorption rates respectively, while other plant foods demonstrate higher: 41% for cabbage [112], 22% for beans [113] or 52% for Chinese cabbage and 48% for broccoli [114]. ...
... This study furthermore emphasizes the particular importance of brassica vegetables in terms of mineral availability. Indeed, previous studies have already shown that brassica vegetables are a good source of available calcium (Heaney, Weaver, Hinders, Martin & Packard, 1993; Lucarini, Canali, Cappelloni, Di Lullo & Lombardi-Boccia, 1999). It is dicult to single out the relative e€ectiveness of each compound in in¯uencing mineral availability, but presumably the generally high level of iron dialysability demonstrated in this study could mainly be ascribed to the high level of organic acids in these vegetables. ...
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Selected vegetables (artichoke, asparagus, broccoli, cauliflower, cabbage, kale, carrot, potato), and some composite dishes (macaroni with vegetables) were analysed for their in vitro iron and zinc dialysability. The effect of red wine on iron dialysability from broccoli, potatoes and their respective composite dishes was also studied. Iron dialysability ranged from 10.7 to 23%, artichokes and asparagus showed lower values (5.7 and 7.7%, respectively). Zinc dialysability ranged from 19.5 to 49.3%. The generally high iron dialysability might be ascribed to organic acids (ascorbic, citric, malic acid). The addition of macaroni to vegetables drastically lowered both iron and zinc dialysability (from 40 to 75%). This effect was dependent on phytate content of macaroni (about 192 mg per dish). A negative relationship between red wine and iron dialysability was found. The decrease in iron dialysability was 45% in broccoli and 70% in macaroni with broccoli, 25% in potatoes and 46% in macaroni with potatoes. Present findings indicate that vegetables may contribute to get a useful level of absorbable iron and zinc in the diet.
... The content of oxalates or fibers (phytate/dietary) seems to be associated with low calcium intake [106][107][108][109]. Indeed, high oxalates in spinach and rhubarb show 5% [110] and 9% [111] absorption rates respectively, while other plant foods demonstrate higher: 41% for cabbage [112], 22% for beans [113] or 52% for Chinese cabbage and 48% for broccoli [114]. ...
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The question of "What's the best diet for children and adolescents which ensures their optimum bone health?" has triggered this review study of all nutritional habits including the Christian Orthodox Church's diet with its particular periods of fasting. In order to evaluate the abstinence from dairy products in childhood and adolescence for more than 180 days per year, we assessed the relative knowledge on vegans and vegetarians in relation to calcium intake. We researched the worldwide published experience as well as studies focused on Christian Orthodox Church's fasting and its contribution to bone health status in children and teenagers with at least one year follow-up randomized controlled trials. During the last 30 years, more than 120 published studies all over the world dispute the generalization that milk consumption during childhood and adolescence relates to "strong bones". Worldwide research experience on vegans and vegetarians reveals that non-diary food resources of calcium fortify the bones, ensure their integrity and development and that calcium daily intake, essential for the bone health, and can be gained from foods other than dairy. Abstinence from dairy products in childhood and adolescence for about 180 days per year-as proposed by the Christian Orthodox Church-seems to act as a means to bone integrity and optimal development.
... . Studies have shown that calcium absorption from various vegetables is either inferior or comparable to calcium absorption from milk with bioavailability estimates ranging between 20 and 40%(133- 135), although Brassica sp. vegetables showed slightly higher absorption(136). Phytate and oxalate content determine the efficiency of calcium absorption from vegetables. ...
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In order to fully exploit the nutrient density concept, thorough understanding of the biological activity of single nutrients in their interaction with other nutrients and food components from whole foods is important. This review provides a narrative overview of recent insights into nutrient bioavailability from complex foods in humans, highlighting synergistic and antagonistic processes among food components for two different food groups, i.e., dairy, and vegetables and fruits. For dairy, bioavailability of vitamins A, B2, B12 and K, calcium, phosphorous, magnesium, zinc and iodine are discussed, whereas bioavailability of pro-vitamin A, folate, vitamin C and K, potassium, calcium, magnesium and iron are discussed for vegetables and fruits. Although the bioavailability of some nutrients is fairly well-understood, for other nutrients the scientific understanding of uptake, absorption, and bioavailability in humans is still at a nascent stage. Understanding the absorption and bioavailability of nutrients from whole foods in interaction with food components that influence these processes will help to come to individual diet scores that better reflect absorbable nutrient intake in epidemiologic studies that relate dietary intake to health outcomes. Moreover, such knowledge may help in the design of foods, meals, and diets that aid in the supply of bioavailable nutrients to specific target groups.
... Vegetable foods are generally considered to provide the body with a small amount of calcium because calcium absorption can be affected by their content of oxalic acids and fiber or dietary fiber, such as spinach; preventing calcium absorption, while foods such as calcium, tahini, almonds and cabbage are low in oxalic acids and therefore their calcium is more easily absorbed 46,47 . The rate of absorption of calcium from milk is about 32%, from cabbage 41% 48 , from beans 22% 49 , and 48% by broccoli 50 . Only high oxalate vegetables such as spinach have a low absorption rate of only 5% 51 . ...
... In case of Calcium, kale is appreciated for its high concentrations and excellent absorbability compared to other salad crops (Gupta & Rana, 2003) and brassica vegetables (Fahey, 2003;Heaney et al., 1993). Kale was reported to have 58.8% of absorption in calcium which is higher than milk (32%). ...
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There has been an increasing trend in recent times for taking more of green leafy vegetables (GLV) portion in the human diet. Among various GLVs available for human consumption, some are confined to a specific region and few are available in many parts of the world. Kale (Brassica oleracea L. var. acephala) is among the latter group which belongs to Brassicaceae family. This review summarizes the nutritional composition and anti-nutritional factors of kale available in different parts of the world. Consideration was also given for summarization of the studies reported on health benefits, pharmacological activities and different food products. It is noted from the literature that kale is a good source of fiber and minerals like potassium with higher calcium bioavailability than that of milk. Kale also contains prebiotic carbohydrates, unsaturated fatty acids and different vitamins while the anti-nutritional factors such as oxalates, tannins and phytate are present in higher concentrations. Research studies are reported different health beneficial activities of the kale like protective role in coronary artery disease, Anti-inflammatory activity, Antigenotoxic ability, gastro protective activity , inhibition of the carcinogenic compounds formation, positive to gut microbes, anti-Neela Satheesh
... rapa, Chinensis group) and broccoli were reported to have a Ca bioavailability around 30% to that of milk. [10] Reports on human bioavailability for the other minerals are unavailable. ...
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During the last decade consumption of broccoli (Brassicaoleracea L. var. italica) has been highly recommended, based on the presence of secondary plant metabolites with health protective effects. Apart from these compounds, broccoli might apport high levels of minerals, however, they are likely to be affected by cultivar, environment and type of inflorescence. Bioavailability of calcium (Ca) in broccoli is compared to milk, reinforcing the importance of this vegetable in human diets. In this study the phosphorus (P), potassium (K), Ca, magnesium (Mg), sulfur (S), and chloride (Cl) content was determined in the primary and secondary inflorescences of 11 broccoli cultivars grown in early and late seasons in order to highlight genotypical differences and seasonal effects on the mineral content. Results showed that the levels of all studied minerals, except K, were influenced by season. Calcium and Cl were higher (P
... Furthermore, the problem of calcium absorption from plant food sources is often mentioned due to the higher content of oxalates (and phytic acid in legumes, cereals and nuts/seeds, for example) in some sources (e.g., spinach) but not in other sources (e.g., broccoli, kale or kiwi), where calcium absorption from broccoli is comparable to milk (41% from broccoli vs. 32% from milk) [256][257][258]. Regardless, according to the abovementioned results of recent European cross-sectional studies that did not estimate an adequate calcium intake among adult vegans [188,189,192,193,195,231,247], it seems to be often a great challenge to consume enough calcium-rich plant foods every day (in comparison, drinking two to three cups of cow's milk seems much easier). ...
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Interest in vegan diets has increased globally as well as in Slovenia. The quantity of new scientific data requires a thorough synthesis of new findings and considerations about the current reserved position of the vegan diet in Slovenia. There is frequently confusion about the benefits of vegetarian diets that are often uncritically passed on to vegan diets and vice versa. This narrative review aims to serve as a framework for a well-designed vegan diet. We present advice on how to maximize the benefits and minimize the risks associated with the vegan diet and lifestyle. We highlight the proper terminology, present the health effects of a vegan diet and emphasize the nutrients of concern. In addition, we provide guidance for implementing a well-designed vegan diet in daily life. We conducted a PubMed search, up to November 2021, for studies on key nutrients (proteins, vitamin B12, vitamin D, omega-3 long chain polyunsaturated fatty acids (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), calcium, iron, zinc, iodine and selenium) in vegan diets. Given the limited amount of scientific evidence, we focus primarily on the general adult population. A well-designed vegan diet that includes a wide variety of plant foods and supplementation of vitamin B12, vitamin D in the winter months and potentially EPA/DHA is safe and nutritionally adequate. It has the potential to maintain and/or to improve health. For physically active adult populations , athletes or individuals with fast-paced lifestyles, there is room for further appropriate sup-plementation of a conventional vegan diet according to individuals' health status, needs and goals without compromising their health. A healthy vegan lifestyle, as included in government guidelines for a healthy lifestyle, includes regular physical activity, avoidance of smoking, restriction of alcohol and appropriate sleep hygiene.
... Los alimen-2 tos de origen vegetal no son buenas fuentes de calcio, algunas plantas, como la espinaca, contienen ácido oxálico que forman sales insolubles con el calcio e inhiben su absorción (27). Vegetales como brócoli, acelga, nabo, rizada tienen bajo contenido de ácido oxálico y son altamente biodisponibles (28). Aunque los granos de soya contienen ácido oxálico, la absorción de calcio es muy buena (29). ...
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The following micronutrients were considered together for their role in bone health: calcium, vitamin D, phosphorus, magnesium and fluoride. Calcium: not enough is known to change current recommendations. In adolescents and adults, limited data suggest that consuming the recommended level is associated with normal bone mass. In older adults, the limited data reported low consumption and a high rate of fractures but there is no information on whether the current values are adequate. Vitamin D: the limited data reported high deficiency in older adults, which was related to osteoporosis. Given the recent increase in North American recommendation for their contribution to bone health, we proposed to increase the recommendation to 400-600 IU/d for Venezuela. Phosphorus, magnesium and fluoride: the lack of local data does not support changing the latest recommendations. Therefore, it highlights the lack of local studies to assess current recommendations. Studies are needed to estimate the intake of these micronutrients in the population and evaluate their interaction and their relation to bone and overall health. Information of the adequacy of these nutrients in human milk for infants is needed. Alto, it is necessary to implement an effective nutrition surveillance system and implement interventions that maximize bone health from an early stage, including the design and implementation of a dairy policy that leads to an increase in production and consumption by the population.
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Butterhead lettuce, rucola, watercress, kale, chicory, cabbage, Chinese cabbage, and a spinach substitute (Tetragonia expansa) are widely consumed in Southern Brazil. Samples were collected five times during a year in food markets and analyzed for total potassium, sodium, calcium, magnesium, iron, manganese, copper, and zinc by flame atomic absorption spectrometry and for moisture content. All vegetables can contribute to diet in terms of potassium, calcium and magnesium. Kale offers the highest amounts of calcium (283±43 mg Ca/100 g) and Chinese cabbage, cabbage, and butterhead lettuce the lowest, with values from 33 to 58 mg Ca/100 g. The highest concentrations of magnesium were found in kale and in the spinach substitute and they were 52±4 and 55±16 mg Ca/100 g, respectively. Moisture content varied less among samples of the same vegetable than minerals did. Four of the vegetables (kale, chicory, Chinese cabbage, and cabbage) were cooked briefly during 3 min and analyzed for the same elements. The brief cooking did not cause appreciable losses for any of the minerals.
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The percentages of total, soluble and dialysable calcium of human milk, cow milk and milk and soy based infant formulas were determined in order to detect possible differences in the calcium bioavailability of the samples. For this purpose an in vitro method was applied to these four calcium sources. The ranking of the analysed samples in terms of calcium bioavailability depends on the criteria applied. Calcium ranked dialysis percentage was: cow milk>human milk>soy based formula>milk based formulas. Calcium ranked solubility percentage was: human milk>cow milk>soy-based formula>milk-based formulas. Comparison of the results of the in vitro assay with the information available on in vivo calcium absorption showed that the total soluble calcium contents agree with the in vivo absorption values better than with calcium dialysis percentages.
Chapter
Early humans are thought to have consumed a diet rich in calcium from a wide range of plant sources (1). With cultivation of plants, a few staple cereal crops became the major source of energy for modern man. Botanically speaking, cereal grains are the fruit of the plant, which is the part of the plant that accumulates the least amount of calcium. Since the agricultural revolution, the main food source of calcium in the diet of most populations is dairy products. Calcium adequacy in the diet became directly related to dairy consumption. In the last few years, an enormous increase in diversity of food sources of calcium has become available in North America through extensive fortification. Now, calcium requirements can be met through consumption of dairy products (primarily milk); through fortified foods; or through supplements.
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The objective of the present investigation was to analyze the relative influence of oxalic acid, phytic acid, tannin and dietary fiber on in vitro availability of iron and calcium from green leafy vegetables (GLV). Thirteen GLV were selected and analyzed for iron, calcium, oxalic acid, phytic acid, tannin and dietary fiber contents using standard methods. The bioavailability of calcium and iron in the GLV was estimated by equilibrium dialysis. Oxalic acid content was less than 1 g kg(-1) in four greens and ranged between 1.22 to 11.98 g kg(-1) in the remaining. Dietary fiber ranged from 19.5 to 113.7 g kg(-1). Tannin content ranged between 0.6138 and 2.1159 g kg(-1) with the exception of two GLV that had 0.1332 and 14.8619 g kg(-1). Four GLV were found to have approximately 40% bioavailable iron, while the others were in the range of 6-30%. In vitro available calcium was less than or equal to 25% in eight GLV and between 34% and 52% in five GLV. Multiple regression analysis revealed that these factors together accounted for 53% (r(2) = 0.53) and 45% (r(2) = 0.45) inhibition of iron and calcium absorption, respectively. These findings infer that calcium and iron availability is influenced by the constituents present in the GLV. (c) 2006 Society of Chemical Industry.
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 Brassicaceae vegetables are considered to be a staple food in many areas all over the world. Brassica species are not only known for their high fat and protein contents for human and animal consumption, but Brassicaceae vegetables are recognized as a rich source of nutrients such as vitamins (carotenoids, tocopherol, ascorbic acid, folic acid), minerals (Cu, Zn, P, Mg, among others), carbohydrates (sucrose and glucose), amino acids (for example, L-alanine, L-aspartic acid, L-glutamic acid, L-glutamine, L-histidine, L-methionine, L-phenylalanine, L-threonine, L-tryptophan, and L-valine), and different groups of phytochemicals such as indole phytoalexins (brassinin, spirobrassinin, brassilexin, camalexin, 1-methoxyspirobrassinin, 1-methoxyspirobrassinol, and methoxyspirobrassinol methyl ether), phenolics (such as feruloyl and isoferuloylcholine, hydroxybenzoic, neochlorogenic, chlorogenic, caffeic, p-coumaric, ferulic, and sinapic acids, anthocyanins, quercetin, and kaempferol), and glucosinolates (mainly glucoiberin, glucoraphanin, glucoalyssin, gluconapin, glucobrassicanapin, glucobrassicin, gluconasturtiin, and neoglucobrassicin). All of these phytochemicals contribute to the reported antioxidant, anticarcinogenic, and cardiovascular protective activities of Brassica vegetables. However, not all members of this family are equal from a nutritional viewpoint, since significant qualitative variations in the phytochemical profiles of Brassica species and varieties suggest differences in the health-promoting properties among these vegetables. In this article, Brassica phytochemicals with their nutritional value and health-promoting activities are discussed to give an overview of the literature for Brassica as a staple crop.
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Five samplings of leaf vegetables widely consumed in Southern Brazil (lettuce, rucola, watercress, kale, chicory, Chinese cabbage, and cabbage) were taken during the period of a year in food markets of the city of Campinas, Brazil. A selective extraction of potassium, sodium, calcium, magnesium, iron, manganese, copper, and zinc was conducted on the raw vegetables and four of the vegetables (kale, chicory, Chinese cabbage, and cabbage) were also cooked briefly under dry heat for three minutes and submitted to the selective extraction. The extraction separated the minerals into fractions containing mineral elements bound to soluble complexes, bound to ligands solubilized by mild acidic oxidizing conditions, and bound to insoluble ligands under mild acidic oxidizing conditions. The minerals concentrations in each fraction were determined by flame atomic absorption spectrometry. The amount of K, Na, Ca, and Mg extractable at pH 7.0 (soluble fraction) from raw vegetables varied between 22 to 75 % of the total content of the mineral present. The soluble fractions of minor elements such as Mn, Zn, and Fe varied from 0 to 100% in the raw vegetables. The brief cooking used besides causing negligible losses of the minerals also increased the solubility of the minerals by 44% to 200%. KEYWORDS: Leaf vegetables; soluble mineral elements in vegetables.
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The vegetable brassicas are consumed in part for their nutritional values of calcium (Ca), magnesium (Mg), potassium (K), iron (Fe), and zinc (Zn). However, information on the genetic variability of elemental accumulation within kale and collards (Brassica oleracea L. var. acephala DC) is limited. Therefore, 22 kale and collard cultivars and selections suitable for the northeastern United States were field grown under similar fertility regimes over two years and evaluated for elemental accumulation. Leaf tissues were analyzed using inductively coupled argon plasma-atomic emission spectrometry. Significant variability among cultivars and selections was observed for tissue Ca, Mg, K, Fe, and Zn. On average, a two-fold difference in elemental accumulation among the cultivars and selections was measured. Tissue Ca levels ranged from 1.2 (“Crimson Garden”) to 3.1% (“NZ Thousand Head”), tissue Mg ranged from 0.3 (“Crimson Garden”) to 0.6% (“NZ Thousand Head”), tissue K ranged from 2.1 (“NZ Thousand Head”) to 3.5% (30665-96G11), tissue Fe ranged from 53.1 (“Winterbor F1”) to 114.2 mg/kg (“Giant Jersey Kale”), and tissue Zn ranged from 29.1 (“Shetland”) to 71.9 mg/kg (“Redbor F1”). Significant year-to-year variability occurred for Ca, Mg, Fe, and Zn accumulation. Despite these yearly changes, ranking of the cultivars and selections for elemental accumulation, as determined by Spearman's rank correlation coefficient, did not change from year 1 to year 2. Overall, the cultivar with the highest elemental leaf accumulation was “Redbor F1”. Information on genotypic variability for elemental accumulation may be important for producers and consumers looking to select kale and collards with higher nutritional levels of beneficial dietary elements.
Article
Calcium (Ca) is an essential nutrient for plants and animals, with key structural and signalling roles, and its deficiency in plants can result in poor biotic and abiotic stress tolerance, reduced crop quality and yield. Likewise, low Ca intake in humans has been linked to various diseases (e.g. rickets, osteoporosis, hypertension and colorectal cancer) which can threaten quality of life and have major economic costs. Biofortification of various food crops with Ca has been suggested as a good method to enhance human intake of Ca and is advocated as an economically and environmentally advantageous strategy. Efforts to enhance Ca content of crops via transgenic means have had promising results. Overall Ca content of transgenic plants has been increased but in some cases adverse affects on plant function have been observed. This suggests that a better understanding of how Ca ions (Ca(2+)) are stored and transported through plants is required to maximise the effectiveness of future approaches.
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Summary of the Thesis: Vegetables have always been considered as healthy food. So also Brassica vegetables are well known all over the world as a common food due to the presence of health affecting compounds (Chapter 2). A vast amount of data is available for health promoting compounds in Brassicaceae vegetables. These health promoting affects are due to a range of phytochemicals including primary (carbohydrates, amino acids and organic acid) and secondary metabolites (phenolics and glucosinolates), along with vitamins and minerals. These metabolites are interconnected through different biosynthetic pathways and are affected by different external stimuli. Plant metabolic responses are specific for different kinds of stress, but use in part similar metabolic pathways (Chapter 3). Certain internal or external factors play an important role for the metabolite profile of vegetables, thus changing the nutritional value for human (Chapter 4). These factors are related to the plant response to external stress factors and helping the plant to survive. These factors includes bacteria (Chapter 5), metals ions ( Chapter 6) and post harvest storage conditions (Chapter 7). The aim of this thesis was to study the Brassica phytochemicals and their response to stress factors by using a holistic analytical approach.
Article
A system for dynamic continuous-flow dialysis during intestinal digestion for an in vitro simulation of gastrointestinal digestion is presented as an alternative to human and animal in vivo methods for estimation of the bioavailability of minerals. The method is based on the in vitro batch dialysis method described by Miller, which was developed into a continuous-flow system of a simple design to perform dynamic dialysis in the intestinal digestion stage. A flow dialysis system has the advantages of simulation being close to in vivo physiological conditions because pH change during dialysis is gradual and dialyzed components are continuously removed. The proposed new design performed dialysis during a continuous flow of dialyzing solution (NaHCO(3)) around a dialysis bag containing peptic digest, which is placed inside a glass dialysis chamber. Gradual change of dialysis pH, similar to that occurring in the gastrointestinal tract, was obtained by optimization of flow rate and concentration of NaHCO(3). The dialysate collected in fractions was analyzed to determine dialyzed minerals and pH change in the course of dialysis. The method was tested by determination of calcium bioavailability of powder milk and calcium carbonate tablets.
Article
To achieve adequate dietary calcium intake, several choices are available that accommodate a variety of lifestyles and tastes. Liberal consumption of dairy products in the diet is the approach of most Americans. Some plants provide absorbable calcium, but the quantity of vegetables required to reach sufficient calcium intake make an exclusively plant-based diet impractical for most individuals unless fortified foods or supplements are included. Also, dietary constituents that decrease calcium retention, such as salt, protein, and caffeine, can be high in the vegetarian diet. Although it is possible to obtain calcium balance from a plant-based diet in a Western lifestyle, it may be more convenient to achieve calcium balance by increasing calcium consumption than by limiting other dietary factors.
Article
The amount of calcium ingested by an individual may affect several chronic conditions, including osteoporosis, hypertension, and colon cancer. However, individuals vary in their ability to absorb the calcium they consume. The purpose of this study was to examine sources of interindividual variation in the efficiency of calcium absorption in women. Fractional calcium absorption was estimated in 142 healthy pre- and perimenopausal women. Dietary habits, lifestyle factors, calciotropic hormones, and vitamin D receptor gene polymorphisms were also assessed. Calcium absorption values averaged 35% and ranged from 17% to 58%. Fractional calcium absorption was positively associated with body mass index (r = 0.22, P = 0.007), dietary fat intake (r = 0.29, P = 0.001), serum 1,25 dihydroxyvitamin D [1,25(OH)(2)D] concentrations (r = 0.23, P = 0. 006), and parathyroid hormone concentrations (r = 0.21, P = 0.015). Fractional calcium absorption was inversely associated with total calcium intake (r = -0.18, P = 0.030), dietary fiber intake (r = -0. 19, P = 0.028), alcohol consumption (r = -0.14, P = 0.094), physical activity (r = -0.22, P = 0.007), and symptoms of constipation (r = -0.16, P = 0.059). In stepwise regression analysis, dietary fat, dietary fiber, serum 1,25(OH)(2)D, and alcohol consumption emerged as independent predictors of calcium absorption, explaining 21.02% of the observed variation. Women in the lowest tertile of the ratio of dietary fat to fiber had 19% lower fractional calcium absorption values than did women in the highest tertile of ratio of dietary fat to fiber (test of trend, P < 0.001). There is a wide range of calcium absorption values in healthy women. The amount of dietary fat consumed relative to dietary fiber appears to have an important role in determining differences in calcium absorption performance among individuals.
Article
Twenty one landraces of cabbage (Brassica oleracea var. capitata L.) and two of Tronchuda cabbage (B. oleracea var. tronchuda Bailey) from Galicia (north–western Spain) along with five commercial hybrids of cabbage and one commercial variety of Tronchuda cabbage were evaluated in this study in two planting dates, autumn/winter for an early harvest and spring/summer for a late harvest. Data were recorded on morphologic, agronomic, nutritional, and sensory traits. The objectives were to assess the characteristics of the Galician cabbage landraces and to compare their agronomic value with that of the commercial hybrids available in local markets, at two planting dates. Four cabbage landraces and the two Tronchuda cabbage landraces showed no head formation. At the autumn/winter season, commercial hybrids showed poor adaptation, with more plants lost after transplanting, less early vigor, and yield than the head forming landraces. However, for characters related to crop uniformity (head appearance, days to harvest, and synchrony of production), commercial hybrids did better than landraces. Regarding the sensory and nutritional values, in the autumn/winter season, accessions were tenderer, sweeter, had a better flavour, and showed higher levels of crude protein and less of crude fibre than in the spring/summer season. Landraces had higher calcium contents compared to commercial varieties. Local landraces MBG-BRS0425, MBG-BRS0452, MBG-BRS0536, and MBG-BRS0537 stood out for the most interesting traits in the autumn/winter season growing period and they could be included in breeding programs to obtain hybrids suitable to grow in this planting period.
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En 2011 un grupo de investigadores, quienes habían participado en la propuesta de valores de referencia del año 2000, publicada por el Instituto Nacional de Nutrición, plantean la necesidad de actualizar los valores de referencia de energía y nutrientes de acuerdo al informe del comité de expertos convocado por FAO/OMS/UNU, publicado en 2004. En el mismo, se recomienda a los países que apliquen la nueva metodología para cálculo del gasto energético de los individuos y la ingesta mínima de calorías, que una persona debería consumir para mantener un adecuado estado de salud físico y mental. La Fundación Bengoa en alianza con ILSI Nor. Andino, apoyan esta iniciativa, debido a que en la última década se han producido cambios significativos en el perfil nutricional y de salud de los venezolanos, necesarios tomar en cuenta en la actualización de los valores de referencia de energía y nutrientes. La convocatoria a las instituciones públicas, académicas y organizaciones de desarrollo social fue amplia y atendieron esta solicitud, el Instituto de Investigaciones Científicas (IVIC), Universidad Central de Venezuela (UCV), Universidad Simón Bolívar (USB), Universidad del Zulia (LUZ), Universidad de los Andes (ULA), CENDES (Centro de Estudios del Desarrollo, UCV), Hospital Universitario de Caracas, Hospital de Niños JM de los Ríos, Centro de Atención Nutricional Infantil Antímano (CANIA), Universidad de Puerto Rico, ILSI Nor Andino (International Life Sciences Institute) y Fundación Bengoa. En esta oportunidad, se presenta la actualización de los valores de Energía, Proteínas, Carbohidratos, Grasas, Hierro, Calcio, Yodo, Zinc, Selenio, Cobre, Fósforo, Magnesio, Molibdeno, Flúor, Vitamina C, Vitamina D, Vitamina K, Vitamina A, Carotenoides, Ácido Fólico, Niacina y Polifenoles.
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  It is envisaged that there will be a considerable demand in the near future for modified starches. To meet the demand, the chemical modification of starch, including cross-linking, has been widely used to obtain desirable traits that are suitable for various food applications. Radiation processing, being a physical process, is an environmentally friendly alternative to chemical modification. It is economically viable, safe, and possesses several advantages over other conventional methods employed for modification and cross-linking. Irradiation of starch leads to the attainment of such desired functional attributes as reduction of viscosity, high water solubility, and others. This review provides insight into the impact of gamma, electron beam, and ultraviolet irradiation on the physicochemical and functional properties of starch. It also highlights the importance and the exciting new opportunities afforded by radiation treatments as a physical means for the modification of starch.
Article
The incorporation of broccoli trimmings into tortilla chips and their effect on the physicochemical, compositional, nutritional and sensory properties was studied. Broccoli flour was added to the formulation at levels of 2%, 4% and 8%. Triangular samples were processed in a lab-scale sheeter, baked, air oven-dried and finally deep fat-fried in fresh canola oil. The addition of broccoli flour significantly increased the protein (from 8.1% to 9.5%), crude fibre (from 1.9% to 3.1%), lysine (from 25.55 g·kg-1 protein to 35.11 g·kg-1 protein) and calcium contents (from 0.45 g·kg-1 to 0.73 g·kg-1) in the fortified tortilla chips. Additionally, the final oil content of tortilla chips was significantly lower (10.5%) in comparison with standard deep fat-fried products. Acceptance test indicated that 76% of participants would definitely prefer either control or tortilla chips prepared with up to 4% broccoli flour, when taste, price, appearance, texture and low fat content were the principal factors influencing the preference. From these results, it is concluded that broccoli flour could be incorporated into an innovative formulation to produce tortilla chips with improved physicochemical and nutritional properties. © 2014 Národné polnohospodárske a potravinárske centrum (Slovakia).
Conference Paper
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The aim of the present study was to analyze the nutritional value in terms of ash content, total polyphenol content (TPC) and antioxidant activity of gluten-free biscuits supplemented with kale powder. Experimental biscuits were prepared from almond flour, coconut flour and kale powder, and the evaluated parameters were compared with the control biscuits (with no addition of kale powder). The results revealed that enriched kale biscuits had higher ash content (2.45±0.05), TPC (0.91±0.02) and antioxidant activity (1.04±0.05) in comparison with the control ones (2.08±0.05; 0.47±0.10; 0.63±0.03, respectively). Thus, it could be concluded that functional biscuits with addition of kale powder have a rich nutritional profile and can be developed as novel gluten-free products on niche food markets with health benefits for the consumer.
Chapter
Die zwei wesentlichen Zugänge, um den eigenen Körper und damit die eigene Biochemie nachhaltig zu verändern, sind Bewegung und Ernährung. Alle Lebewesen dieser Erde haben gemein, dass sie, damit sie überleben können, wichtige Bausteine über die Ernährung zuführen müssen. Damit dies geschieht, müssen sich die Lebewesen vorher bewegt haben. Nahrungszufuhr und Bewegung müssen damit nicht nur enormen Einfluss auf die Gesundheit der Lebewesen haben – viel mehr noch sind Nahrungszufuhr und Bewegung eng gekoppelt. Es gibt einige wesentliche Gesetze, die bei der Ernährungsplanung zu berücksichtigen sind und die heute oft vernachlässigt werden. Zudem zeigen viele neuere Untersuchungen, dass der Muskel, wenn er gut ernährt und bewegt wird, Botenstoffe ausschüttet, die in anderen Geweben eine gesunderhaltende Wirkung hervorrufen. Dennoch gilt auch für den Sport, dass das Bewegungsmuster, das viele Leistungs- und Hobbysportler heute an den Tag legen, nicht konform mit jener Art von Bewegung ist, an die wir genetisch angepasst sind.
Chapter
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Calcium carbonate is a chemical compound with the formula CaCO3 formed by three main elements: carbon, oxygen, and calcium. It is a common substance found in rocks in all parts of the world (most notably as limestone), and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. CaCO3 exists in different polymorphs, each with specific stability that depends on a diversity of variables.
Article
This book has 19 chapters focusing on the beneficial effects of the consumption of fruits and vegetables on human health. Some of the most common fruits and vegetables, their biologically active constituents and their medicinal properties are discussed. Some methodologies used for the extraction, isolation, characterization and quantification of these biologically active compounds and evaluation of their in vitro and in vivo activities are also presented.
Article
BACKGROUND Attempts were made to identify and characterize the calcium binding proteins (CaBPs) in grain filling stages of finger millet using proteomics, bioinformatics and molecular approaches. RESULTS A distinctly observed blue color band of 48 kDa stained by Stains-all was eluted and analyzed as calreticulin (CRT) using nano liquid chromatography–tandem mass spectrometry (nano LC-MS). Based on the top hits of peptide mass fingerprinting results, conserved primers were designed for isolation of the CRT gene from finger millet using calreticulin sequences of different cereals. The deduced nucleotide sequence analysis of 600 bp amplicon showed up to 91% similarity with CRT gene(s) of rice and other plant species and designated as EcCRT1. Transcript profiling of EcCRT1 showed different levels of relative expression at different stages of developing spikes. The higher expression of EcCRT1 transcripts and protein were observed in later stages of developing spikes which might be due to greater translational synthesis of EcCRT1 protein during seed maturation in finger millet. CONCLUSIONS Preferentially higher synthesis of this CaBP during later stages of grain filling may be responsible for the sequestration of calcium in endoplasmic reticulum of finger millet grains. © 2015 Society of Chemical Industry
Article
A hydroponic growth procedure which enables the intrinsic 42Ca-labelling of green beans (Phaseolus vulgarisL) has been developed. Whole-plant Ca influx was measured from planting through the period of pod expansion for a crop of 60 plants grown hydroponically in a 3m2area. Total Ca influx was 10·1mmol per plant; 35% of this influx occurred during the period of pod growth. Plants were labelled with 42Ca via the nutrient solution during the period of pod expansion; isotopic composition of harvested pods was nearly identical to that of the administered solution. Recovery of isotopic tracer at harvest was as follows: pods 8·4%; leaves, 61·1%; stems, 17·1%, roots, 9·0%. Pod yield was 98·8g FW per plant. 42Ca-labelled green beans can be used safely to investigate Ca bioavailability in humans.
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The project of updating the Venezuelan energy reference values respond to the recommendations made by an FAO experts committee, several decades ago for the countries assuming this work. Because of the dramatic changes experienced globally regarding energy intake/expenditure and particularly variations on the Venezuelan nutritional scenario with the presence of "the double burden of malnutrition" it a review of Energy Reference Values (VRE) from a more integral approach is pertinent. This report follows the methodology proposed by FAO/WHO/UNU 2004 experts committee and energy reference values were established by group of age and gender, also average energy values for Venezuelan population were obtained. For calculation of these requirements, the energy expenditure was included by taking into account Basal Metabolic Rate and physical activity level for some specific groups. The score average values updated in 2012 of 2.200 kcal/dia reported to be lower than those of 2000 at all ages for masculine gender except for the 16-17 age group and for feminine gender just until ages 10-12 years and from there are slightly above the values obtained in 2000.
Article
Background Attempts were made to identify and characterize the calcium binding proteins (CaBPs) in grain filling stages of finger millet using different omics approaches.ResultsA distinctly observed blue color band of 48 kDa stained by Stains-all was eluted and analyzed as calreticulin (CRT) using Nano liquid chromatography tandem mass spectrometry (Nano LC–MS). Based on the top hits of peptide mass fingerprinting results, conserved primers were designed for isolation of the CRT gene from finger millet using calreticulin sequences of different cereals. The deduced nucleotide sequence analysis of 600 bp amplicon showed upto 91% similarity with CRT gene(s) of rice and other plant species and designated as EcCRT1. Transcript profiling of EcCRT1 showed different level of relative expression at different stages of developing spikes. The higher expression of EcCRT1 transcripts and protein were observed in later stages of developing spikes which might be due to greater translational synthesis of EcCRT1 protein during seed maturation in finger millet.Conclusions Preferentially higher synthesis of this CaBP during later stages of grain filling may be responsible for the sequestration of calcium in endoplasmic reticulum of finger millet grains.
Article
Calcium is a divalent mineral cation that functions as an intracellular messenger in virtually all life forms. In multicellular organisms it functions also as an integrator tying body systems together, and in land-living vertebrates it provides the principal mineral component of the endoskeleton (bone). Calcium cannot be synthesized and must be ingested, first to build an adult skeleton and then to maintain it. Because calcium was abundant in the terrestrial vertebrate diet, humans, like most mammals, did not develop mechanisms to absorb or retain calcium efficiently, and human physiology is optimized to defend against calcium excess rather than calcium deficiency. Unfortunately, modern diets have low calcium densities, and for that reason contemporary humans face the threat of calcium deficiency. Since calcium is regularly lost from the body through skin and excreta, it must be replaced with ingested calcium. If not, the body tears down units of bone in order to scavenge their calcium. This is the context in which calcium functions in bone health. This chapter describes the details of the operation of the calcium economy and sets forth calcium intake requirements, the factors that influence them, and calcium sources, both from foods and from supplements.
Article
To achieve adequate dietary calcium intake, several choices are available that accommodate a variety of lifestyles and tastes. Liberal consumption of dairy products in the diet is the approach of most Americans. Some plants provide absorbable calcium, but the quantity of vegetables required to reach sufficient calcium intake make an exclusively plant-based diet impractical for most individuals unless fortified foods or supplements are included. Also, dietary constituents that decrease calcium retention, such as salt, protein, and caffeine, can be high in the vegetarian diet. Although it is possible to obtain calcium balance from a plant-based diet in a Western lifestyle, it may be more convenient to achieve calcium balance by increasing calcium consumption than by limiting other dietary factors.
Article
Full-text available
For early prevention or inhibition of postmenopausal and age-related bone loss, nutritional interventions might be a first choice. For some vitamins and minerals an important role in bone metabolism is known or suggested. Calcium and vitamin D support bone mineral density and are basic components in most preventive strategies. Magnesium is involved in a number of activities supporting bone strength, preservation, and remodeling. Fluorine and strontium have bone-forming effects. However, high amounts of both elements may reduce bone strength. Boron is especially effective in case of vitamin D, magnesium, and potassium deficiency. Vitamin K is essential for the activation of osteocalcin. Vitamin C is an important stimulus for osteoblast-derived proteins. Increasing the recommended amounts (US RDA 1989), adequate intakes (US DRI 1997), or assumed normal intakes of mentioned food components may lead to a considerable reduction or even prevention of bone loss, especially in late postmenopausal women and the elderly.
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1. The effect of dietary fibre digestion in the human gut on its ability to alter bowel habit and impair mineral absorption has been investigated using the technique of metabolic balance. 2. Five healthy male students were studied for 9 weeks under controlled dietary conditions and during the last 6 weeks they took 36 g pectin/d. Bowel habit, transit through the gut, faecal fibre excretion, calcium balance and faecal composition were measured. 3. During the control period only 15% of the dietary fibre ingested was excreted in the stools and when pectin was added to the diet there was no increase in fibre excretion. Stool frequency and mean transit time were unchanged by pectin but stool wet weight increased by 33% and faecal excretion increased (%) for fatty acids 80, nitrogen 47, total dry matter 28 and bile acids 35. Ca balance remained unchanged. 4. It may be concluded from these results that dietary fibre is largely metabolized in the human gut and dietary pectin completely so. This could explain its lack of effect on bowel habit and Ca balance. Other changes in the faeces may be related to an increase in bacterial mass.
Article
A rapid colorimetric procedure is described for determination of phytate based on the reaction between ferric ion and sulfosalicylic acid. Determination of the phytate content of a variety of cereals, legumes, and oilseeds demonstrates the simplicity of this method compared to the cumbersome digestion and colorimetric method for measuring liberated phosphorus.
Article
Calcium bioavailability (BV) from sesame seeds, almond powder, whole wheat bread, spinach, and nonfat dry milk (NFDM) was compared to calcium BV from a calcium carbonate (CaCO3)-supplemented control diet using a rat model. When comparing different calcium sources, the relative BV of the products was CaCO3 (100%), NFDM (100%) whole wheat bread (95%), almond powder (66%), sesame seeds (65%), NFDM and spinach mixture (52%), and spinach (47%). Separate almond, NFDM, and CaCO3 diets were supplemented with 0.4% ascorbic acid; vitamin C addition had no significant effect on calcium BV.
Article
True calcium absorption was studied as a function of the size of the ingested load in healthy adult women, under meal conditions and at loads ranging from 15 to 500 mg calcium. Fractional absorption was highly inversely correlated with the logarithm of load (P < 0.001). At the lowest loads, absorption averaged 64.0% and at the highest, 28.6%. The parameters of the best-fit relationship permit reasonably precise calculation of the impact of various calcium dosing and dietary strategies.
Article
Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre will reduce the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids will liberate the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity of the colon for calcium absorption.
Article
Absorption of calcium from intrinsically labeled kale was measured in 11 normal women and compared in these same subjects with absorption of calcium from labeled milk. The average test load was 300 mg. Fractional calcium absorption from kale averaged 0.409 +/- 0.101 (means +/- SD) and from milk, 0.321 +/- 0.089 (P less than 0.025). In contrast with the poor absorption previously reported for spinach calcium, kale, a low-oxalate vegetable, exhibits excellent absorbability for its calcium.
Article
The absorbability of calcium from spinach was compared with the absorbability of Ca from milk in 13 healthy adults in a randomized cross-over design in which the test meal of either milk or spinach had 200 mg of Ca labeled with 45Ca. Absorption was measured by the standard double-isotope method in which both the test food and the miscible Ca pool are labeled with different Ca tracers. Measurement of both Ca and oxalate in our test spinach revealed a very slight stoichiometric excess of oxalate; hence it is likely that all of the spinach Ca was effectively bound. Absorption was higher from milk in every case, with the mean absorption from milk averaging 27.6% and from spinach, 5.1%. The mean within-subject difference between Ca absorption from milk and from spinach was 22.5 +/- 9.5% (P less than 0.0001). These results conclusively establish that spinach Ca is much less readily available than milk Ca.
Article
Calcium absorption from salts and foods intrinsically labeled with 45Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO3 and CaCl2 than from CaC2O4 (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach.
Article
The fate of minerals can be conveniently studied through intrinsic labeling techniques. The mineral of interest is biologically incorporated into the food in a form that can be distinguished analytically from the natural form of the element. Radiolabels have traditionally been used to study such problems as the uptake of minerals by plants, the gross and subcellular mineral distribution in plant tissues, the form and associations of the deposited mineral, and the bioavailability of minerals to animals and humans. The use of stable (nonradioactive) isotopes as a label offers the potential of safely studying bioavailability of minerals from individual foods in human population groups of all ages using foods processed in normal food handling and processing facilities.
Article
Measurements of true calcium absorption fraction in women were evaluated to see how closely calculations based on a single measurement of serum specific activity after administration of an oral calcium tracer might approximate the absorption value derived from the full, double-isotope absorption procedure. True absorption, body size, and miscible pool turnover could together explain better than 93% of the variance in serum calcium specific activity values 5 hours after a tracer-labeled test meal. Because measurement of pool turnover is not available routinely, it was dropped from the model, and a predictor equation was developed that allowed estimation of true absorption from the 5-hour serum specific activity value, height, and weight. These variables explained 90.8% of the variance in the 5-hour values and gave estimates of true absorption with a 95% confidence interval of +/- 0.055. This small range of uncertainty makes the procedure useful in estimating absorption efficiency for calcium therapy in routine clinical practice.
Article
Certain soluble plant fibers have hypocholesterolemic effects. However, information about soluble fibers of most foods is not available. A modification of Southgate's method was used to separate plant fiber into soluble and insoluble fractions. Both fractions were hydrolyzed with dilute sulfuric acid or trifluoracetic acid. Comparison of these two hydrolysis methods was discussed. The hydrolyzed sugars were measured by gas-liquid chromatography. Fiber content of selected cereals and vegetables were examined. Oat, corn, and cooked beans have greater proportions of soluble fiber than wheat and green vegetables. Soluble fractions of cereals and beans were mainly glucose whereas in green vegetables uronic acids were the major components. The differing fiber composition of various plant food sources probably is important in determining their physiological effects.
Article
An in vitro method for measuring dietary mineral exchangeability (miscibility with an extrinsic isotopic tracer) was tested by comparison with in vivo measurements in rats. Collards, spinach and soybeans, intrinsically labeled with 45Ca, were fed to rats together with extrinsically added 47Ca. Absorption of both tracers was determined by measuring their concentrations in the femur 2 days after consumption of the labeled test meals. The same intrinsically and extrinsically labeled foods were digested in vitro for estimation of Ca exchangeability and solubility after peptic-pancreatic digestion. Corresponding in vivo and in vitro estimates of exchangeability agreed closely for the three foods tested. Solubility after in vitro peptic-pancreatic digestion (potential bioavailability) showed discrepancies. In vitro values were somewhat higher for collards than in vivo fractional absorption. The reverse was true for Ca in soybeans and spinach. Thus, the in vitro procedure appears adequate for measuring intrinsic dietary Ca exchangeability but requires modification if it is to be a reliable substitute for in vivo measurements of Ca bioavailability.
Association of OfiiciaI Analytical Chemists An Introduction to the Botany o the Mqjor Crop Plants Soluble and lnmiuble plant fiber in selected cereals and vegetables
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AOAC. 1984. Official Methods of Analysis, 14th ed. Association of OfiiciaI Analytical Chemists, Arlington, VA Berrie, AM.M. 1977. An Introduction to the Botany o the Mqjor Crop Plants, p. 122-135. Heyslen & Son, Ltd., Bellmawr,. Id Chen, W.&L. and Anderson, J.W. 1987. Soluble and lnmiuble plant fiber in selected cereals and vegetables. Am. J. CIin. Nutr. 34: 1077-1082.