Calcium intake: good for the bones but bad for the heart? An analysis of clinical studies

Abstract

The proper dietary calcium intake and calcium supplementation, when indicated, are important factors in the acquisition of peak bone mass during youth and in the prevention of fractures in old age. In addition to its deposition in bone, calcium confers an increase in its resistance and exhibits important activities in different enzymatic pathways in the body (e.g., neural, hormonal, muscle-related and blood clotting pathways). Thus, calcium supplementation can directly or indirectly affect important functions in the body, such as the control of blood pressure, plasma glucose, body weight, lipid profile and endothelial function. Since one publication reported increased cardiovascular risk due to calcium supplementation, many researchers have studied whether this risk actually exists; the results are conflicting, and the involved mechanisms are uncertain. However, studies that have evaluated the influence of the consumption of foods rich in calcium have reported no increase in the cardiovascular risk, which suggests that nutritional intake should be prioritized as a method for supplementation and that the use of calcium supplements should be reserved for patients who truly need supplementation and are unable to achieve the recommended daily nutritional intake of calcium. Arch Endocrinol Metab.2016;60(3):252-63

Overactive bladder and associated psychological symptoms: A possible link to vitamin D and calcium

“…A result that might be mediated through the role that calcium plays in nervous system function . Apparently, 45.5% of the patients had less than a quarter of the recommended daily calcium intake (1000‐1300 mg/day) for 19 to 70 years old …”

Calcium supplementation in osteoporosis: useful or harmful?

“…In the impossibility to obtain a correct calcium intake through diet, calcium with concomitant vitamin D supplements should be given as, in this setting, they have to be considered an effective therapy for reducing the fragility fracture risk (71). This idea is also reinforced by the fact that the reported cardiovascular risk due to calcium supplementation has yet to be demonstrated and that studies that have evaluated the influence of dietary calcium intake did not show increase in the cardiovascular risk (28). Therefore, the debated issue of the use of calcium supplements is perhaps more simple to resolve than expected.…”

“…Further complicating matters, the national Recommendations on calcium intake for different ages and genders vary worldwide (20), being for example between 1000 and 1300 mg/day in those from the US National Institutes of Health (26) and between 700 and 1000 mg/day in those from the National Osteoporosis Society (27). In general, even if these latter recommendations defines 400 mg/day as the lowest amount of calcium required to maintain a healthy skeleton (28), the adequate calcium supplementation for bone health is still a matter of debate and it is influenced by several factors, such as age and vitamin D levels (17). It is clear, therefore, that the different calcium intake among the different populations may be an important confounding factor in interpreting the results of the studies on the effect of calcium supplements on bone, since data from Page 4 of 32 randomized controlled trials were not able to be adjusted for baseline personal calcium intake without making subgroups analyses with the consequent loss of the randomized design (6).…”

“…The importance of the calcium intake during adolescence has been evidenced by a recent double blind randomized controlled trial on 220 Chinese teens showing that, after two years of low, medium or high calcium intake levels, the BMD increases in female adolescents who ingested more calcium (28,29). In keeping, some data suggest that BMD is reduced and the fracture is increased in adult women who drunk less milk during childhood and adolescence (30).…”

The Effect of Additive Formula Diet on Bone Structure of the Femur in Ovariectomized Rats

“…Low calcium intake and vitamin D level in blood were considered as risk factors for osteoporosis, and improving their intake is considered effective, especially for the elderly with micronutrient deficiency due to inadequate drug intake secondary to chronic disease 4) . However, the effect of these interventions is ambiguous [5][6][7] . Aiming at efficient intake and absorption of calcium, 215 Nakada et al 8,9) fed ovariectomized osteoporosis-model rats a supplement composed of fructo-oligosaccharide (FOS), isoflavone (ISO) and phosphate Ca (3.0% content), and found a significant effect on bone formation and strength, and quality of the femoral shaft.…”