Dietary Mineral Intake Ratios and Bone Health in Adults

Fruit and vegetable consumption has consistently been identified as a favorable dietary strategy for bone health. Diets high in fruits and vegetables tend to be high in several minerals that are advantageous for bone health, including potassium, calcium, and magnesium, and low in sodium. The role of calcium in bone health has been well-characterized. However, there are few studies examining the link between potassium, magnesium, and sodium and bone. Moreover, characterizing the relationships between individual mineral intakes and their ratios and health outcomes is important due to the interactive effects of these minerals. Therefore, the aim of this study was to characterize the relationships between sodium, potassium, calcium, and magnesium intake and their ratios and bone mineral density and fracture incidence in a representative sample of US adults. We used data from the National Health and Nutrition Examination Survey (NHANES), 2013–2014, for these analyses. We included adult men and women ≥40 years of age, who were not pregnant or lactating, with complete and plausible data (n = 2617). Diet was assessed using two 24-h dietary recalls. Total femur and femoral neck areal bone mineral density (aBMD) were assessed using DXA, and fracture incidence after age 20 years was determined by self-report. A model for predicting bone outcomes was developed using the following explanatory variables: age, race, height, weight, and smoking status (yes/no). Relationships between individual mineral intakes and mineral intake ratios and bone outcomes were assessed by adding each of these terms to the basic regression model separately. Body weight explained the largest proportion of the variance in total femur aBMD (29% in women, 21% in men) and femoral neck aBMD (22% in women, 15% in men), and race explained the largest proportion of the variance in fracture incidence in both women (3%) and men (2%). Sodium, potassium, calcium, and magnesium intakes were positive predictors of aBMD in men (all p 0.05). Randomized, controlled, full-feeding studies are required to determine the effect of mineral consumption from food as well as the ratio of their intakes on bone outcomes. Such findings would have important implications for making dietary recommendations and designing dietary interventions for reducing fracture risk.