Influence of Dietary Calcium Intake on Skeletal Health and Body Composition in an Italian Elderly Population

Background: Calcium is the most abundant mineral in the human body and is essential not only for bone health but also for many other physiological functions. In fact, dietary calcium intake is important not only for bone health but also for fat mass and overall body composition. This study aimed to evaluate the potential effects of dietary calcium intake on bone mineral density (BMD), body composition, and fragility fractures. Methods: In a cohort of 173 consecutive elderly men and 939 women aged 55 and over, living in Siena, Italy, daily dietary calcium intake was evaluated using a food frequency questionnaire (FFQ) specifically validated for the Italian population. Bone mineral density at various skeletal sites and body composition were measured in all participants using a Lunar Prodigy densitometer. Additionally, the serum levels of vitamin D and bone turnover markers were assessed, and the presence of prevalent atraumatic fractures was documented. Results: Across all age groups, calcium intake was consistently higher in males (898.40 ± 312.87 mg/day) than in females (821.95 ± 351.3 mg/day); the prevalence of subjects in the lowest tertile of calcium intake was significantly higher among females than males (31.4% vs. 14.5% p < 0.05). Moreover, dietary calcium intake showed an inverse relationship with body fat mass in women (p < 0.05) and a positive association with lean mass in men (p < 0.05). Two hundred twenty-eight (24.3%) women and forty-eight (27.8%) men had a history of one or more fractures, and in both sexes, subjects with prevalent fractures had significantly lower dietary calcium intake values than those without fractures. Conclusions: This study indicates that inadequate calcium intake remains widespread in the Italian population, especially among subjects with low BMD and a history of fractures. Furthermore, this study confirms that dietary calcium intake significantly affects body composition.