Calcium is an essential element that plays numerous biological functions in the human body, of which one of the most important is skeleton mineralization. Bone is a mineralized connective tissue in which calcium represents the major component, conferring bone strength and structure. Proper dietary calcium intake is important for bone development and metabolism, and its requirement can vary throughout life. The mineral composition of drinking water is becoming relevant in the modulation of calcium homeostasis. In fact, calcium present in mineral drinking waters is an important quantitative source of calcium intake. This, together with its excellent bioavailability, contributes to the maintenance of the bone health. This article aims to examine studies that assessed the bioavailability of the calcium contained in calcium-rich mineral waters and their impact on bone health, including original data collected in a recent study in humans.

Osteoporosis is a complex multifactorial disorder of the skeleton. Genetic factors are important in determining peak bone mass and structure, as well as the predisposition to bone deterioration and fragility fractures. Nonetheless, genetic factors alone are not sufficient to explain osteoporosis development and fragility fracture occurrence. Indeed, epigenetic factors, representing a link between individual genetic aspects and environmental influences, are also strongly suspected to be involved in bone biology and osteoporosis. Recently, alterations in epigenetic mechanisms and their activity have been associated with aging. Also, bone metabolism has been demonstrated to be under the control of epigenetic mechanisms. Runt-related transcription factor 2 (RUNX2), the master transcription factor of osteoblast differentiation, has been shown to be regulated by histone deacetylases and microRNAs (miRNAs). Some miRNAs were also proven to have key roles in the regulation of Wnt signalling in osteoblastogenesis, and to be important for the positive or negative regulation of both osteoblast and osteoclast differentiation. Exogenous and environmental stimuli, influencing the functionality of epigenetic mechanisms involved in the regulation of bone metabolism, may contribute to the development of osteoporosis and other bone disorders, in synergy with genetic determinants. The progressive understanding of roles of epigenetic mechanisms in normal bone metabolism and in multifactorial bone disorders will be very helpful for a better comprehension of disease pathogenesis and translation of this information into clinical practice. A deep understanding of these mechanisms could help in the future tailoring of proper individual treatments, according to precision medicine’s principles.

In the recent years, both the prescriptions of serum 25(OH)D levels assay, and vitamin D supplementation are constantly increasing, as well as the costs to be incurred relating to these specific aspects. As in many other countries, the risk of vitamin D deficiency is particularly high in Italy, as recently confirmed by cohort studies in the general population as well as in patients with metabolic bone disorder. Results confirmed the North-South gradient of vitamin D levels described among European countries, despite the wide use of supplements. Although vitamin D supplementation is also recommended by the Italian Medicine Agency for patients at risk for fragility fracture or for initiating osteoporotic medication, the therapeutic gap for osteoporosis in Italy is very high. There is a consistent proportion of osteoporotic patients not receiving specific therapy for osteoporosis following a fragility fracture, with a poor adherence to the recommendations provided by national guidelines and position paper documents. The failure or inadequate supplementation with vitamin D in patients on antiresorptive or anabolic treatment for osteoporosis is thought to further amplify the problem and exposes patients to a high risk of re-fracture and mortality. Therefore, it is important that attention to its possible clinical consequences must be given. Thus, in light of new evidence from the literature, the SIOMMMS board felt the need to revise and update, by a GRADE/PICO system approach, its previous original recommendations about the definition, prevention, and treatment of vitamin D deficiency in adults, released in 2011. Several key points have been here addressed, such as the definition of the vitamin D status: normality values and optimal values; who are the subjects considered at risk of hypovitaminosis D; opportunity or not of performing the biochemical assessment of serum 25(OH)D levels in general population and in subjects at risk of hypovitaminosis D; the need or not to evaluate baseline serum 25(OH)D in candidate subjects for pharmacological treatment for osteoporosis; how and whether to supplement vitamin D subjects with hypovitaminosis D or candidates for pharmacological treatment with bone active agents, and the general population; how and whether to supplement vitamin D in chronic kidney disease and/or chronic liver diseases or under treatment with drugs interfering with hepatic metabolism; and finally, if vitamin D may have toxic effects in the subject in need of supplementation.

Hip fractures are a major health issue considerably impacting patients’ quality of life and well-being. This is particularly evident in elderly subjects, in which the decline in bone and muscle mass coexists and predisposes individuals to fall and fracture. Among interventions to be implemented in hip fractured patients, the assessment and management of nutritional status is pivotal, particularly in subjects older than 65. Nutrition plays a central role in both primary and secondary preventions of fracture. An adequate protein intake improves muscle mass and strength and the intestinal absorption of calcium. Other nutrients with recognized beneficial effects on bone health are calcium, vitamins D, K, and C, potassium, magnesium, folate, and carotenoids. With reference to calcium, results from longitudinal studies showed that the consumption of dairy foods has a protective role against fractures. Moreover, the most recent systematic reviews and meta-analyses and one umbrella review demonstrated that the combination of calcium and vitamin D supplementation significantly reduces hip fracture risk, with presumed higher efficacy in older and institutionalized subjects. Owing to these reasons, the adequate intake of calcium, vitamin D, protein, and other macro and micronutrients has been successfully implemented in the Fracture Liaison Services (FLSs) that represent the most reliable model of management for hip fracture patients. In this narrative review, papers (randomized controlled trials, prospective and intervention studies, and systematic reviews) retrieved by records from three different databases (PubMed, Embase, and Medline) have been analyzed, and the available information on the screening, assessment, and management of nutritional and vitamin D status and calcium intake in patients with hip fractures is presented along with specific prevention and treatment measures.