Adsorption isotherms for water vapor, c-spacing and heat of immersion in water of mixed Na/Ca-montmorillonite were measured at 25°C at various RH. There was good agreement between the calorimetric data, the heat calculated from the isotherms by use of BET equation, and the calculations from the ion-dipole model. It was concluded that the electrostatic forces between the adsorbed cations and the water molecules are the dominant forces in the hydration of the clay. Thus, at low moisture content, only the adsorbed Ca-ions are hydrated. The heat released when Na-platelets condense to form Ca-packets was measured, and it was suggested that this energy term is the driving force for the demixing phenomena.

The crystallization of calcium zeolites was carried out in an open hydrothermal system at 100°–250°C, using reactants that in nature are known to alter to calcium zeolites and 0.1 N CaCl2, 0.01 N CaCl2, and 0.01 N CaCl2 + 0.01 N NaOH (1:1) solutions. The following calcium zeolites were identified by X-ray powder diffraction:

• Rhyolitic glass: heulandite, phillipsite, epistilbite, wairakite;

• Basaltic glass: phillipsite, scolecite, wairakite, levynite;

• Nepheline: thomsonite, wairakite, gismondine;

• Oligoclase: heulandite, phillipsite, wairakite.

Factors that influenced the type of zeolite formed were: Si/Al ratio of the starting material, calcium/alkali ratio of the starting material, calcium activity of the reacting solution, presence of an open alteration system, and temperature. The Si/Al ratio of the starting material was of special importance in that zeolites formed with Si/Al ratios similar to or smaller than that of the parent material. The calcium/alkali ratio of the starting material also influenced the kind of the early alteration products in the open system. As alteration progressed, the importance of the starting material decreased. The importance of the calcium activity of the reacting solution and the influence of the open system increased as alteration proceeded. Because of mass transfer during alteration in the open system, the calcium content of the minerals formed increased, while their Si/Al ratio decreased. Temperature was especially effective during prolonged alteration, in that the higher the alteration temperature the smaller was the H2O content of the alteration product. Initially, H2O-rich zeolites formed transitorily at higher temperatures.

Weight loss or fad diets are often promoted for rapid weight loss and by unqualified individuals and celebrities. There is sometimes limited information around the nutritional adequacy of the diet. Some diets require fasting, some modify macronutrient composition, and some restrict food groups, such as dairy foods, resulting in suboptimal intake of nutrients like calcium, potentially leading to nutrient deficiencies and disease such as osteoporosis if followed long-term. We assessed the total dairy food and calcium content of five popular weight loss diets (Intermittent Fasting, Ketogenic, Optifast, Paleolithic, 8 Weeks to Wow; 8WW), and two government recommended healthy eating principles (Australian Guide to Healthy Eating; AGHE, and Mediterranean diet; MedDiet, for weight loss). Meal plans from each diet were analysed using Foodworks Dietary Software and compared with government recommendations and dietary reference values (DRV) in Australia, the United States and Ireland to give the percentage of the recommended intake of dairy food and calcium, met by each diet(1). Intermittent Fasting, Ketogenic and AGHE provided the most serves of dairy foods with 2.8, 2.3 and 2.2 serves/d, respectively, whilst 8WW, MedDiet, and Optifast provided 1.4, 1.3 and 1 serve/d each, respectively, and Paleolithic 0.02 serves/d. None of the dietary patterns met all government recommendations for dairy serves. Milk was the most common source of dairy food in all dietary patterns except for Ketogenic (cheese), MedDiet (yoghurt) and Paleolithic. The Ketogenic diet provided the highest calcium content (1293mg/d), followed by Intermittent Fasting (1230mg/d) and Optifast (1212mg/d). Non-dairy sources contributed to 93% of the calcium content (385mg/d) of the Paleolithic diet, 70% for Optifast and 61% in the MedDiet (631mg/d). None of the dietary pattens met all dietary reference values for calcium. There are no universal dietary recommendations for dairy foods or calcium, making cross country comparisons of dietary recommendations difficult. Only the Intermittent Fasting diet met the dietary recommendations in Australia for dairy serves for males 19-70 and females 19-50 years. None of the other diets met any recommendation for Australia, the US and Ireland. Most dietary patterns met the estimated average requirement for age and gender, for calcium for Australia, the US and Ireland, apart from the Paleolithic diet which eliminates dairy foods and the MedDiet which is naturally low in dairy foods. These data indicate that several popular weight-loss diets do not meet dietary recommendations for dairy foods or calcium. Therefore, when considering a weight loss diet or dietary pattern, it is crucial to consider the nutritional adequacy, to ensure macro and micronutrient requirements are met for health and avoidance of nutritional deficiencies, particularly if followed long-term.

Cow’s milk is the primary source of calcium in the NZ diet(1). The absence of dietary planning in a vegan diet can result in the individual unknowingly obtaining low intakes of calcium. Prolonged low calcium intakes can result in negative implications on bone mineral density by increasing the risk of osteoporosis later in life. The measurement of bone health parameters in NZ vegan adults have not been investigated. Therefore, we measured bone mineral density, markers of calcium homeostasis and assessed intake of essential nutrients for optimal bone health in vegans. This cross-sectional study included adults (>18yrs), who followed a vegan diet for 2 years minimum. Demographic and lifestyle information was obtained from questionnaires including previous history of bone fractures and background of familial osteoporosis. A 4-day food record was completed for analysis of calcium, zinc, protein, magnesium, phosphorus and vitamin C intake and compared to the Estimated Average Requirement (EAR)(2). Weight, height and BMI were obtained, bone mineral density was measured at the hip and spine via dual x-ray absorptiometry (DXA) and reported as Z and T scores. Plasma calcium concentrations were corrected for albumin. All values are presented as mean and standard deviation. The study included 212 participants, aged 39 ± 12.38 years, 71% female. T scores at the lumbar spine and femoral neck were −0.63 ± 1.22 (Z score: −0.29 ± 1.12) and −0.66 ± 1.00 (Z score: −0.24 ± 0.89), respectively. Nine participants had a Z-score of <-2.0 at the lumbar spine, and three at the femoral neck. Corrected calcium concentrations were 2.21 ± 0.33 mmol/L. Calcium intake was 917 ± 347.23 (range 195 to 2,429 mg/day) in all participants, which exceeded the EAR of 840 mg/day for adults aged 19-50 years. Men had higher intakes of calcium than women, 1,051 ± 363.7 mg/day (range 382 to 2,267 mg/day) vs. 867 ± 328.04 mg/day (range 194 to 2,428 mg/day), P-value <0.001. The main source of calcium in the vegan diet was tofu. The intake of protein (77 ± 27.80) g/day, magnesium (569 ± 181.05) mg/day, and vitamin C (145 ± 96.94) mg/day met the EAR, excluding vitamin and mineral supplements. However, the intake of phosphorus (1,472 ± 459.98) mg/day and zinc (10.6 ± 4.01) mg/day were below the EAR. The findings of this study suggest that bone health of vegans are not negatively affected by the exclusion of dairy in the diet, provided that appropriate dietary planning is included to avoid nutrient deficiencies associated with poor bone health. Despite mean intake of calcium exceeding the EAR, very low intakes demonstrated significant variations between participants.

This study was conducted to determine the effect of reducing calcium (Ca) and available phosphorus (AvP) on performance, carcass yield, tibia traits and jejunum histomorphology in broilers. For this purpose, 480 one-day-old Ross 308 male chicks were distributed into four trial groups with eight subgroups. During the starter period, birds were fed with recommended or reduced Ca and AvP contents of 66.7 and 62.5 g/kg, respectively. Calcium and AvP contents of the groups were as follows: control: 8.70 g/kg Ca, 4.40 g/kg AvP for grower and 7.80 g/kg Ca, 3.90 g/kg AvP for finisher; LCP1: 8.30 g/kg Ca, 4.20 g/kg AvP for grower and 7.10 g/kg Ca, 3.50 g/kg AvP for finisher; LCP2: 7.90 g/kg Ca, 4.00 g/kg AvP for grower and 6.00 g/kg Ca, 3.00 g/kg AvP for finisher; LCP3: 7.00 g/kg Ca, 3.80 g/kg for grower and 5.00 g/kg Ca, 3.00 g/kg AvP for finisher. Performance variables have been calculated from the data of each period, and samples were obtained from the slaughtered birds on the final day of the trial (42nd day) for carcass and tibia traits and jejunum histomorphology. Reducing dietary Ca and AvP did not affect the broiler performance, carcass yield and mortality. Tibia ash decreased in LCP2 and LCP3 groups (P < 0.01). Villus width and villus surface area increased in LCP2 and LCP3. Overall, feeding with a diet 100 g/kg lower than the recommended Ca and AvP did not affect performance in broilers, but improved jejunal development.

Clinoptilolite from the Fort LaClede deposit in Sweetwater County, Wyoming, shows a moderate selectivity for NH4− over Na+ in aqueous solution. At 30°C, the standard free energy of this replacement reaction is −0.7 kcal/mole at an ionic strength of 0.05 M and −0.8 kcal/mole at 0.5 M. The Na+-NH4+ exchange is complete within 3 days in agitated solution and proceeds to the same extent from the clinoptilolite saturated with either cation.

The Ca2+-Na+ exchange also is complete within 3 days in agitated aqueous solution and proceeds to the same extent from either the calcium or the sodium form of the zeolite. Using test methods which take into account the slower equilibration of Ca2+-loaded clinoptilolite, the cation-exchange capacity is substantially the same over the full range of loading by Ca2+ and Na+. Ca2+ replaces Na+ with decreasing selectivity as Ca2+ loading increases to about 80% at 30°C (95% at 63°C), above which the selectivity reverses. The standard free energy of replacement of two Na+ ions by one Ca2+ ion in 0.05 M solution is −1.2 ± 0.2 kcal/mole at 63°C and −0.3 to −0.8 kcal/mole at 30°C.

The aim of this study was to assess whether adding Ca2+ to aggregate or native forms of β-lactoglobulin alters gut hormone secretion, gastric emptying rates and energy intake in healthy men and women. Fifteen healthy adults (mean ± sd: 9M/6F, age: 24 ± 5 years) completed four trials in a randomised, double-blind, crossover design. Participants consumed test drinks consisting of 30 g of β-lactoglobulin in a native form with (NATIVE + MINERALS) and without (NATIVE) a Ca2+-rich mineral supplement and in an aggregated form both with (AGGREG + MINERALS) and without the mineral supplement (AGGREG). Arterialised blood was sampled for 120 min postprandially to determine gut hormone concentrations. Gastric emptying was determined using 13C-acetate and 13C-octanoate, and energy intake was assessed with an ad libitum meal at 120 min. A protein × mineral interaction effect was observed for total glucagon-like peptide-1 (GLP-1TOTAL) incremental AUC (iAUC; P < 0·01), whereby MINERALS + AGGREG increased GLP-1TOTAL iAUC to a greater extent than AGGREG (1882 ± 603 v. 1550 ± 456 pmol·l−1·120 min, P < 0·01), but MINERALS + NATIVE did not meaningfully alter the GLP-1 iAUC compared with NATIVE (1669 ± 547 v. 1844 ± 550 pmol·l−1·120 min, P = 0·09). A protein × minerals interaction effect was also observed for gastric emptying half-life (P < 0·01) whereby MINERALS + NATIVE increased gastric emptying half-life compared with NATIVE (83 ± 14 v. 71 ± 8 min, P < 0·01), whereas no meaningful differences were observed between MINERALS + AGGREG v. AGGREG (P = 0·70). These did not result in any meaningful changes in energy intake (protein × minerals interaction, P = 0·06). These data suggest that the potential for Ca2+ to stimulate GLP-1 secretion at moderate protein doses may depend on protein form. This study was registered at clinicaltrials.gov (NCT04659902).

Calcium and vitamin D have well-established roles in maintaining calcium balance and bone health. Decades of research in human subjects and animals have revealed that calcium and vitamin D also have effects on many other organs including male reproductive organs. The presence of calcium-sensing receptor, vitamin D receptor, vitamin D activating and inactivating enzymes and calcium channels in the testes, male reproductive tract and human spermatozoa suggests that vitamin D and calcium may modify male reproductive function. Functional animal models have shown that vitamin D deficiency in male rodents leads to a decrease in successful mating and fewer pregnancies, often caused by impaired sperm motility and poor sperm morphology. Human studies have to a lesser extent validated these findings; however, newer studies suggest a positive effect of vitamin D supplementation on semen quality in cases with vitamin D deficiency, which highlights the need for initiatives to prevent vitamin D deficiency. Calcium channels in male reproductive organs and spermatozoa contribute to the regulation of sperm motility and capacitation, both essential for successful fertilisation, which supports a need to avoid calcium deficiency. Studies have demonstrated that vitamin D, as a regulator of calcium homoeostasis, influences calcium influx in the testis and spermatozoa. Emerging evidence suggests a potential link between vitamin D deficiency and male infertility, although further investigation is needed to establish a definitive causal relationship. Understanding the interplay between vitamin D, calcium and male reproductive health may open new avenues for improving fertility outcomes in men.

Plant-based substitutes (PBS) are seen as a convenient way to transition to a more plant-based diet, but their potential health benefits and nutritional concerns remain debated. Based on a review of the literature, it is concluded here that the primary risk of insufficient nutrient intake with PBS concerns iron and calcium, which are critical to the nutritional value of PBS. Other risks were identified but these would depend on the characteristics of the overall diet, as is the case for iodine in a diet containing no seafood or dairy, and vitamin B12 in a vegetarian/vegan diet. Conversely, the use of PBS is also expected to confer some benefits for long-term health because it would result in higher fibre intakes (in the case of meat PBS) and lower SFA intakes (but higher PUFA/MUFA intakes), but attention should be paid to a potential increase in sodium intake with PBS of meat products. In fact, a recurring finding in this review was that PBS is a very heterogeneous food category involving considerable variations in ingredient and nutrient composition, and whose design could be improved in order to foster nutritional and health benefits. The latter also depend on the animal food that is being replaced and are only deemed likely when PBS replace red meat. The fortification of PBS with key nutrients such as iron and calcium may constitute an actionable public health solution to further shift the balance in favour of PBS in the context of the current dietary transition in western countries.

Vitamin D deficiency is common in Irish adults, though there is limited research on its determinants, knowledge of vitamin D or indications for testing. We aimed to explore the determinants of vitamin D status in adults and examine knowledge and reasons for testing. The study population comprised adults who had serum 25-hydroxyvitamin D tested by general practitioners request at a Dublin Hospital in 2020. Questionnaires detailing dietary intake, sun exposure, ethnicity, biophysical factors and vitamin D knowledge were sent to a sample stratified by age, sex and vitamin D status. In total, there were 383 participants, mean age 56·0 (sd 16·6) years. Wintertime deficiency disproportionally affected non-white v. white (60 % v. 24 %, P < 0·001). The greatest predictors of deficiency were low vitamin D intake (< 10 μg/d) (P < 0·001) and non-white ethnicity (P = 0·006), followed by sun avoidance (P = 0·022). It was also more prevalent in those with lower body exposure when outdoors. The majority (86 %) identified vitamin D as important for bone health. However, 40 % were tested for non-clinical indications and half were not aware of the recommended daily allowance (RDA). Low vitamin D intake was the most important determinant of deficiency, but ethnicity and sun exposure habits were also significant predictors. The majority had no clear indication for testing and were not aware of the RDA. Public health policies to improve knowledge and vitamin D intake, especially for those of non-white ethnicity and with reduced sun exposure, should be considered.

Calcium content in the diet can affect egg quality and production in aged birds. Calcium pidolate is a new form of calcium supplementation in poultry diets, which favours the absorption of this mineral. The current study was conducted to evaluate the effect of dietary calcium pidolate concentration in the diets of aged laying Japanese quails. A total of 120 female quails (27 weeks old) were assigned to four treatment groups, each with six replicates of five quails per pen. In the 10-week trial, quail diets were supplemented with calcium pidolate at four concentrations (0, 0.25, 0.50 and 1.00 g/kg), providing 25.1, 25.4, 25.8 and 26.5 g/kg calcium, respectively. As a result of this study, body weight, feed intake and feed conversion ratio did not change with the concentration of calcium pidolate (P > 0.05). In contrast, albumen and yolk index decreased as calcium pidolate level increased (P < 0.05). Moreover, calcium pidolate at a concentration of 0.50 g/kg resulted in the greatest egg production, eggshell breaking strength and eggshell thickness (P < 0.05), while above these levels the factors studied were negatively affected. According to these results, the optimal concentration of calcium pidolate in the diets of aged laying quails was 0.50 g/kg.

The role of dietary factors in osteoporotic fractures (OFs) in women is not fully elucidated. We investigated the associations between incidence of OF and dietary calcium, magnesium and soy isoflavone intake in a longitudinal study of 48 584 postmenopausal women. Multivariable Cox regression was applied to derive hazard ratios (HRs) and 95 % confidence intervals (CIs) to evaluate associations between dietary intake, based on the averages of two assessments that took place with a median interval of 2⋅4 years, and fracture risk. The average age of study participants is 61⋅4 years (range 43⋅3–76⋅7 years) at study entry. During a median follow-up of 10⋅1 years, 4⋅3 % participants experienced OF. Compared with daily calcium intake ≤400 mg/d, higher calcium intake (>400 mg/d) was significantly associated with about a 40–50 % reduction of OF risk among women with a calcium/magnesium (Ca/Mg) intake ratio ≥1⋅7. Among women with prior fracture history, high soy isoflavone intake was associated with reduced OF risk; the HR was 0⋅72 (95 % CI 0⋅55, 0⋅93) for the highest (>42⋅0 mg/d) v. lowest (<18⋅7 mg/d) quartile intake. This inverse association was more evident among recently menopausal women (<10 years). No significant association between magnesium intake and OF risk was observed. Our findings provide novel information suggesting that the association of OF risk with dietary calcium intake was modified by Ca/Mg ratio, and soy isoflavone intake was modified by history of fractures and time since menopause. Our findings, if confirmed, can help to guide further dietary intervention strategies for OF prevention.

Ascidians (Urochordate) are hermaphroditic marine invertebrates that release sperm and eggs to the surrounding seawater. However, several ascidians, including Ciona intestinalis and Halocynthia roretzi, show strict self-sterility due to a self/nonself-recognition mechanism in the interaction between sperm and the vitelline coat (VC) of the eggs. We have previously reported that sperm intracellular Ca2+ level drastically increased immediately after sperm binding to the VC of self eggs but not nonself eggs in C. intestinalis type A, which was potently inhibited by lowering the external Ca2+ concentration, suggesting that sperm Ca2+ influx occurs after sperm self-recognition on the VC. Here, we investigated whether self-sterility was abolished by lowering the external Ca2+ concentration in C. intestinalis. The results showed that the block to self-fertilization was removed by low-Ca2+ (∼1 mM) seawater without decreasing the fertilization rate. Such an effect was not observed with Mg2+ or K+. These results led us to conclude that a low-Ca2+ environment is sufficient to block the self-recognition signal upon fertilization. As low-Ca2+ seawater showed no effect on H. roretzi self-sterility, we propose that the mechanism of self-sterility in Ciona must be distinctive from that in Halocynthia.

Sixty growing male pigs were used to test the hypothesis that high dietary Ca content reduces P absorption to a greater extent in microbial phytase-supplemented diets via reducing inositol phosphate (IP) degradation and enhancing P precipitation. Pigs were equally allotted over diets with three Ca contents 2·0, 5·8 and 9·6 g/kg with or without microbial phytase (0 v. 500 FTU/kg) in a 2 × 3 factorial arrangement. Faeces and urine were collected at the end of the 21-d experimental period. Subsequently, pigs were euthanised and digesta quantitatively collected from different gastrointestinal tract (GIT) segments. Increasing dietary Ca content reduced apparent P digestibility in all GIT segments posterior to the stomach (P < 0·001), with greater effect in phytase-supplemented diets in the distal small intestine (Pinteraction = 0·007) and total tract (Pinteraction = 0·023). Nonetheless, increasing dietary Ca to 5·8 g/kg enhanced P retention, but only in phytase-supplemented diets. Ileal IP6 degradation increased with phytase (P < 0·001) but decreased with increasing dietary Ca content (P = 0·014). Proportion of IP esters in total IP (∑IP) indicated that IP6/∑IP was increased while IP4/∑IP and IP3/∑IP were reduced with increasing dietary Ca content and also with a greater impact in phytase-supplemented diets (Pinteraction = 0·025, 0·018 and 0·009, respectively). In all GIT segments, P solubility was increased with phytase (P < 0·001) and tended to be reduced with dietary Ca content (P < 0·096). Measurements in GIT segments showed that increasing dietary Ca content reduced apparent P digestibility via reducing IP degradation and enhancing P precipitation, with a greater impact in phytase-supplemented diets due to reduced IP degradation.

Milk, dairy products, and fish are the main sources of iodine in the UK. Plant-based products are increasingly popular, especially with young women, which may affect iodine intake as they are naturally low in iodine; this is concerning as iodine is required for fetal brain development. We, aimed to (i) assess the iodine fortification of products sold as alternatives to milk, yoghurt, cheese and fish through a cross-sectional survey of UK retail outlets in 2020, and (ii) model the impact of substitution with such products on iodine intake, using portion-based scenarios. We identified 300 products, including plant-based alternatives to: (i) milk (n 146); (ii) yoghurt (n 76); (iii) cheese (n 67) and (iv) fish (n 11). After excluding organic products (n 48), which cannot be fortified, only 28 % (n 29) of milk alternatives and 6 % (n 4) of yoghurt alternatives were fortified with iodine, compared with 88 % (n 92) and 73 % (n 51), respectively, with Ca. No cheese alternative was fortified with iodine, but 55 % were fortified with Ca. None of the fish alternatives were iodine fortified. Substitution of three portions of dairy product (milk/yoghurt/cheese) per day with unfortified alternatives would reduce the iodine provided by 97·9 % (124 v. 2·6 µg) and substantially reduce the contribution to the adult intake recommendation (150 µg/d; 83 v. 1·8 %). Our study highlights that the majority of plant-based alternatives are not iodine fortified and that the use of unfortified alternatives put consumers at risk of iodine deficiency.

The intracellular localization of Ca2+, Ca2+-ATPase, Calmodulin, and Calbindin D-28KD have been studied in testes of the toad Leptodactylus chaquensis, using ultracytochemical and immunohistochemical techniques. The Ca2+ presences in the nucleus and into the mitochondria of the germ cells, together with the activity of Ca2+-ATPase detected in the nuclear envelope and mitochondrial crests, suggest the participation of this transporter in the storage of Ca2+. In Sertoli cells, Ca2+ deposits were also found in vesicles and lamellar bodies. Calmodulin and Calbindin D-28KD were revealed in the cytoplasm of both cell types. At the spermatozoon level, the cation deposits were located in the subacrosomal space and in the acrosomal vesicle. Ca2+-ATPase activity was observed in the acrosomal and plasma membranes of the gamete that suggests the existence of a transport system responsible for maintaining low cytoplasmic Ca2+ levels. The activity of Ca2+-ATPase and the location of Ca2+ deposits in gamete tail would be related to flagellar movement. The colocalization of Ca2+ deposits and their binding proteins in efferent duct cells would probably be associated with secretory activity. Considering that intracellular Ca2+ is present in different gonadal cells, this work would provide a better understanding of the cation importance in the testicular functions of this species.