Calcium and Bone

Anti-osteoporotic potential of a probiotic mixture containing Limosilactobacillus reuteri and Weissella cibaria in ovariectomized rats

Postmenopausal osteoporosis poses a significant clinical challenge, as conventional therapies are often ineffective or poorly tolerated owing to adverse effects or underlying health conditions, underscoring the need for alternative treatments. This study investigated the anti-osteoporotic effects of a novel probiotic mixture combining Limosilactobacillus reuteri MGE 3301 (LR) and Weissella cibaria MGE 3110 (WC), which were selected for their anti-inflammatory properties and ability to modulate bone metabolism, in an ovariectomized rat model. Thirty-five female Wistar rats were randomly assigned to five groups: Sham, Ovariectomy (OVX), OVX with LR supplementation (OVX/LR), OVX with WC (OVX/WC), and OVX with a combination of LR and WC (OVX/LR/WC), under ARRIVE guidelines and ethical approval. Each probiotic group received 1 × 10⁹ CFU/mL/day for 16 weeks starting at 5 weeks post-OVX. Micro-computed tomography and histopathological analyses revealed that the OVX/LR/WC group had superior trabecular bone preservation compared with that in the OVX control group, with significant improvements in bone mineral density (+ 54.2%), bone volume fraction (+ 24.8%), trabecular thickness (+ 13.6%), and trabecular number (+ 20%), along with decreased trabecular separation (- 8.1%; p < 0.05). RT-qPCR analysis of bone marrow demonstrated that LR/WC suppressed osteoclastogenic mediators (RANKL: -1.35-fold; TNF-α: -2.5-fold; IL-6: -1.9-fold) while elevating osteoprotective osteoprotegerin expression (+ 3.14-fold; p < 0.05). Serum analysis showed reduced CTX-I (- 38.9%) and elevated calcium (+ 30.8%) levels in OVX/LR/WC versus OVX rats (p < 0.05), indicating suppressed bone resorption and enhanced mineral homeostasis. These findings indicate that LR/WC probiotic supplementation attenuates OVX-induced bone loss by modulating bone turnover markers and inflammatory cytokines. To our knowledge, this is the first study to assess the combined effects of LR and WC in an osteoporosis animal model, highlighting its potential as an adjunctive therapeutic candidate for osteoporosis. However, few notable imitations include undefined human dosing and the unassessed long-term safety of probiotics. Future clinical trials must validate the efficacy, elucidate mechanisms (e.g., gut-bone axis interactions), and assess safety in postmenopausal women to advance therapeutic applicability.

Strategies for preventing bone loss in populations with insufficient calcium and vitamin D intake

Calcium and vitamin D are essential nutrients for maintaining skeletal health, yet deficiencies in these nutrients are particularly widespread in regions such as Asia and Africa. Inadequate intake of these nutrients in these areas has been associated with diminished bone integrity and a rising incidence of osteoporosis. This review examines the underlying mechanisms of bone loss driven by calcium and vitamin D deficiencies, emphasizing their crucial roles in bone metabolism. It also presents strategies to improve nutrient intake, such as fortification of staple foods and supplementation, along with lifestyle modifications including increased physical activity, sun exposure, and dietary education, to prevent bone loss effectively. Special consideration is given to vulnerable populations, including older adults, individuals with limited sun exposure, and those with dietary restrictions, who are at higher risk of deficiency. The review further evaluates public health strategies, including government-initiated fortification and educational programs, as essential measures for tackling widespread nutrient deficiencies. Lastly, it explores future avenues for addressing calcium and vitamin D deficiencies, including the potential role of digital health tools, personalized nutrition, and innovative public health policies to alleviate the global burden of bone-related diseases.

De Novo Hypercalcaemia in a Patient With Chronic Hypoparathyroidism

Calcium Homeostasis in the human body is regulated by hormones, including parathyroid hormone and vitamin D3. Dysfunction in the form of hypoparathyroidism causes hypocalcaemia. In patients treated for primary hypoparathyroidism with activated vitamin D replacement, iatrogenic hypercalcaemia can occur. This must be investigated to exclude other aetiologies, such as malignancy and granulomatous disease. In this case report, we describe a 73-year-old man with a distant history of chronic hypoparathyroidism treated with vitamin D3 who presented with lethargy, confusion, polyuria, and polydipsia. On admission, he was found to be hypercalcaemic at 3.22 mmol/L. He presented on two previous occasions with symptomatic hypocalcaemia that resulted in a reduction and subsequent cessation of his vitamin D supplementation. This hypercalcaemia persisted, prompting investigations of non-iatrogenic causes. Computer tomography (CT) and positron emission tomography (PET) scans showed bilateral hilar lymphadenopathy and ruled out malignancy. Serum angiotensin-converting enzyme was three times the normal range while calcitriol levels were inappropriately raised, suggesting sarcoidosis as the likely aetiology of the hypercalcaemia. The patient was very responsive to steroid therapy, with serum calcium dropping to normal levels over a four-week admission. The patient developed hypocalcaemia within weeks of discharge, eventually requiring the recommencement of his vitamin D replacement, which has been titrated to maintain normal serum calcium levels. This case highlights a rare occurrence of two infiltrative disorders with simultaneous differential adverse effects on calcium metabolism, leading to a series of acute hospitalisations often alternating between severe hypocalcaemia or severe hypercalcaemia.

Feasibility of increasing calcium content of drinking tap water following quality regulations to improve calcium intake at population level

Background

Calcium intake is below recommendations in several parts of the world. Improving calcium intake has benefits not only for bone health but also helps to prevent pregnancy hypertension disorders. Calcium concentration of tap water is usually low The aim of the present study was to determine the maximum amount of calcium that can be added to tap water while complying with drinking water Argentine regulations.

Methods

Tap water samples were collected from the Province of Buenos Aires (Argentina). Physicochemical properties and saturation index were measured. Different incremental concentrations of calcium chloride were added to the experimental aliquots.

Results

Baseline water had a mean calcium concentration of 22.00 ± 2.54 mg/L, water hardness of 89.9 ± 6.4 mg/L CaCO 3, and a saturation index of -1.50 ± 0.11. After the addition of 0.4554 ± 0.0071 g of salt, water hard-ness reached 355.0 ± 7.1 mg/L CaCO 3, a calcium concentration of 140.50 ± 2.12 mg/L, and a saturation index -0.53 ± 0.02.

Conclusions

This study shows that at laboratory level it is feasible to increase calcium concentration of drinking water by adding calcium chloride while complying with national standards. Calcium concentration of drinking tap water could be evaluated and minimum calcium concentration of tap water regulated so as to improve calcium intake in populations with low calcium intake.

Regional and Age-Related Variations in Blood Calcium Levels among Patients with Plasmodium falciparum and P. vivax malaria: A Systematic Review and Meta-Analysis

Despite several studies examining the relationship between calcium levels and malaria, inconsistencies and varied results remain in the literature. This study aimed to synthesize the evidence on the association between blood calcium levels and malaria severity. A systematic literature search was conducted in the Embase, Scopus, PubMed, Ovid, and Google Scholar databases. The studies that investigated calcium levels in participants with malaria were reviewed and included for synthesis. The quality of included studies was assessed based on a standardized checklist by the Joanna Briggs Institute (JBI) critical appraisal checklists. The thematic synthesis had been used for qualitative synthesis. For the quantitative synthesis, the meta-analysis was performed to estimate the pooled effect sizes for differences in calcium levels between groups of participants using a random effect model using Hedge's g as a measure of effect size. Out of the 4574 identified records, 14 studies were reviewed. The thematic synthesis across these studies noted a consistent theme: reduced calcium levels in malaria patients compared to uninfected controls. However, the meta-analysis encompassing three specific analyses-comparing calcium levels between malaria patients and controls, severe and non-severe malaria cases, and fatal cases versus survivors-showed no significant difference in calcium levels. The statistics were as follows: (1) p = 0.15, Hedge's g: -1.00, 95% CI: -2.37-0.38, I2: 98.97, 9 studies; (2) p = 0.35, Hedge's g: -0.33, 95% CI: -1.02-0.36, I2: 81.61, 3 studies; and (3) p = 0.71, Hedge's g: -0.14, 95% CI: -0.91-0.62, I2: 87.05, 3 studies. Subgroup analyses indicated that regional disparities, especially between Africa and Asia, and participant age groups may influence these outcomes. While a trend of decreased calcium levels in malaria patients was observed, the meta-analytical results suggest regional and age-related variations. Further investigations should emphasize these differences to better guide clinical management, prognostic applications, and the crafting of policies concerning malaria's metabolic effects.

Effect of Calcium Fortified Foods on Health Outcomes: A Systematic Review and Meta-Analysis

Calcium supplementation and fortification are strategies widely used to prevent adverse outcome in population with low-calcium intake which is highly frequent in low-income settings. We aimed to determine the effectiveness and cost-effectiveness of calcium fortified foods on calcium intake and related health, or economic outcomes. We performed a systematic review and meta-analysis involving participants of any age or gender, drawn from the general population. We searched PubMed, Agricola, EMBASE, CINAHL, Global Health, EconLit, the FAO website and Google until June 2019, without language restrictions. Pair of reviewers independently selected, extracted data and assessed the risk of bias of included studies using Covidence software. Disagreements were resolved by consensus. We performed meta-analyses using RevMan 5.4 and subgroup analyses by study design, age group, and fortification levels. We included 20 studies of which 15 were randomized controlled trials (RCTs), three were non-randomised studies and two were economic evaluations. Most RCTs had high risk of bias on randomization or blinding. Most represented groups were women and children from 1 to 72 months, most common intervention vehicles were milk and bakery products with a fortification levels between 96 and 1200 mg per 100 g of food. Calcium intake increased in the intervention groups between 460 mg (children) and 1200 mg (postmenopausal women). Most marked effects were seen in children. Compared to controls, height increased 0.83 cm (95% CI 0.00; 1.65), plasma parathyroid hormone decreased -1.51 pmol/L, (-2.37; -0.65), urine:calcium creatinine ratio decreased -0.05, (-0.07; -0.03), femoral neck and hip bone mineral density increased 0.02 g/cm2 (0.01; 0.04) and 0.03 g/cm2 (0.00; 0.06), respectively. The largest cost savings (43%) reported from calcium fortification programs came from prevented hip fractures in older women from Germany. Our study highlights that calcium fortification leads to a higher calcium intake, small benefits in children's height and bone health and also important evidence gaps for other outcomes and populations that could be solved with high quality experimental or quasi-experimental studies in relevant groups, especially as some evidence of calcium supplementation show controversial results on the bone health benefit on older adults.