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.

This review reports in detail the cellular and molecular mechanisms which regulate the bone remodeling process in relation to oxidative stress (OS), inflammatory factors, and estrogen deficiency. OS is considered an important pathogenic factor of osteoporosis, inducing osteocyte apoptosis and varying levels of specific factors, such as receptor activator κB ligand (RANKL), sclerostin, and, according to recent evidence, fibroblast growth factor 23, with consequent impairment of bone remodeling and high bone resorption. Bone loss increases the risk of fragility fractures, and the most commonly used treatments are antiresorptive drugs, followed by anabolic drugs or those with a double effect. In addition, recent data show that natural antioxidants contained in the diet are efficient in preventing and reducing the negative effects of OS on bone remodeling and osteocytes through the involvement of sirtuin type 1 enzyme. Indeed, osteocytes and some of their molecular factors are considered potential biological targets on which antioxidants can act to prevent and reduce bone loss, as well as to promote bone anabolic and regenerative processes by restoring physiological bone remodeling. Several data suggest including antioxidants in novel therapeutic approaches to develop better management strategies for the prevention and treatment of osteoporosis and OS-related bone diseases. In particular, anthocyanins, as well as resveratrol, lycopene, oleuropein, some vitamins, and thiol antioxidants, could have protective and therapeutic anti-osteoporotic effects.

This study comprised a comprehensive analysis of the glutathione (GSH) redox system during osteogenic differentiation in human osteoblast‐like SaOS‐2 cells. For the first time, a clear relationship between expression of specific factors involved in bone remodeling and the changes in the GSH/oxidized GSH (GSSG) redox couple induced during the early phases of the differentiation and mineralization process is shown. The findings show that the time course of differentiation is characterized by a decrease in the GSH/GSSG ratio, and this behavior is also related to the expression of osteoclastogenic markers. Maintenance of a high GSH/GSSG ratio due to GSH exposure in the early phase of this process increases mRNA levels of osteogenic differentiation markers and mineralization. Conversely, these events are decreased by a low GSH/GSSG ratio in a reversible manner. Redox regulation of runt‐related transcription factor‐2 (RUNX‐2) activation through phosphorylation is shown. An inverse relationship between RUNX‐2 activation and extracellular signal‐regulated kinases related to GSH redox potential is observed. The GSH/GSSG redox couple also affects osteoclastogenesis, mainly through osteoprotegerin down‐regulation with an increase in the ratio of receptor activator of NF‐κB ligand to osteoprotegerin and vice versa. No redox regulation of receptor activator of NF‐κB ligand expression was found. These results indicate that the GSH/GSSG redox couple may have a pivotal role in bone remodeling and bone redox‐dysregulated diseases. They suggest therapeutic use of compounds that are able to modulate not just the GSH level but the intracellular redox system through the GSH/GSSG redox couple.

Objectives: As osteoporotic fractures are becoming a major health care problem in countries characterized by an increasing number of older adults, in this study we aimed to compare the incidence and costs of hip fragility fractures in Italian elderly people versus those of major cardiovascular diseases (strokes and acute myocardial infarctions [AMI]) occurring in the whole adult population. Methods: We analyzed hospitalization records maintained at the national level by the Italian Ministry of Health for the diagnosis of hip fractures (ICD-9-CM codes 820–821), AMI (code 410), hemorrhagic (codes 430, 431, 432) and ischemic strokes (codes 433–434), and TIA (code 435) between 2001–2005. Cost analyses were based on diagnosis-related groups. Results: The incidence of hip fractures in elderly people has increased (+12.9% between 2001 and 2005), as well as that of AMI (+20.2%) and strokes (hemorrhagic: +9.6%; ischemic: +14.7) occurring in the whole adult population; conversely, hospitalization due to TIA decreased by a rate of 13.6% between 2001 and 2005. In 2005, the hospital costs across the national health care system that were associated with hip fragility fractures in the elderly were comparable to those of strokes (both hemorrhagic and ischemic), which occurred in the whole Italian adult population. Moreover, these costs were higher than those generated by AMI and TIA. Rehabilitation costs following strokes reached about 3 billion Euros in 2005, but rehabilitative costs of hip fractures and AMI were comparable (about 530 million Euros in 2005). Conclusion: The burden of hip fragility fractures in Italy is comparable to that of AMI and strokes.