Calcium deficiency worldwide: prevalence of inadequate intakes and associated health outcomes

Abstract

Dietary calcium deficiency is considered to be widespread globally, with published estimates suggesting that approximately half of the world's population has inadequate access to dietary calcium. Calcium is essential for bone health, but inadequate intakes have also been linked to other health outcomes, including pregnancy complications, cancers, and cardiovascular disease. Populations in low-and middle-income countries (LMICs) are at greatest risk of low calcium intakes, although many individuals in high-income countries (HICs) also do not meet recommendations. Paradoxically, many LMICs with lower calcium intakes show lower rates of osteoporotic fracture as compared with HICs, though data are sparse. Calcium intake recommendations vary across agencies and may need to be customized based on other dietary factors, health-related behaviors, or the risk of calcium-related health outcomes. The lack of standard methods to assess the calcium status of an individual or population has challenged efforts to estimate the prevalence of calcium deficiency and the global burden of related adverse health consequences. This paper aims to consolidate available evidence related to the global prevalence of inadequate calcium intakes and associated health outcomes, with the goal of providing a foundation for developing policies and population-level interventions to safely improve calcium intake and status where necessary.

Calcium status assessment at the population level: Candidate approaches and challenges

“…Ideally, the prevalence of a specific disease that is associated with calcium intake would be a good indicator of calcium status in that population. However, there are several limitations in assuming an association between average calcium intake and the prevalence of certain diseases (discussed in more detail in this Special Issue 8 ): There are limited high‐quality datasets that include both dietary calcium intake and disease prevalence parameters. Moreover, when data are available, they are more likely to be from high resource settings, which tend to have greater proportions of older adults (who, in turn, are more prone to osteoporosis and bone fractures). Diseases are multifactorial, and as such there are many other risk factors (e.g., genetics, physical activity, and vitamin D status) that modify the association between calcium intake and these diseases. There are associations that may be real at the individual level but might not be apparent or consistent at the population level. …”

“…4 Ideally, the prevalence of a specific disease that is associated with calcium intake would be a good indicator of calcium status in that population. However, there are several limitations in assuming an association between average calcium intake and the prevalence of certain diseases (discussed in more detail in this Special Issue 8 ): There are limited high‐quality datasets that include both dietary calcium intake and disease prevalence parameters. Moreover, when data are available, they are more likely to be from high resource settings, which tend to have greater proportions of older adults (who, in turn, are more prone to osteoporosis and bone fractures).…”

“…Overall calcium status depends on many factors, including consumption of calcium‐rich foods and supplements, the bioavailability of the calcium consumed, age, sex, vitamin D status, and genetic variability in calcium retention and absorption 1,5 . Adding to the complexity of assessing calcium status is an inconsistent relationship between low calcium intakes and adverse health outcomes 6–8 . Furthermore, there is no consensus among nutritionists and researchers regarding the health consequences of long‐term low calcium intakes and suboptimal calcium status.…”

“…1,5 Adding to the complexity of assessing calcium status is an inconsistent relationship between low calcium intakes and adverse health outcomes. [6][7][8] Furthermore, there is no consensus among nutritionists and researchers regarding the health consequences of long-term low calcium intakes and suboptimal calcium status. Unlike many other micronutrients for which a circulating ion or metabolite concentration may be used as a biomarker of nutritional status (e.g., zinc, retinol, and ferritin), the concentration of calcium in the blood is tightly regulated within a narrow range by endocrine feedback mechanisms and, therefore, cannot be interpreted as a marker of calcium nutriture or status.…”

“… 1 , 5 Adding to the complexity of assessing calcium status is an inconsistent relationship between low calcium intakes and adverse health outcomes. 6 , 7 , 8 Furthermore, there is no consensus among nutritionists and researchers regarding the health consequences of long‐term low calcium intakes and suboptimal calcium status.…”