Essential Nutrient Interactions: Does Low or Suboptimal Magnesium Status Interact with Vitamin D and/or Calcium Status?

Abstract

Although much is known about magnesium, its interactions with calcium and vitamin D are less well studied. Magnesium intake is low in populations who consume modern processed-food diets. Low magnesium intake is associated with chronic diseases of global concern [e.g., cardiovascular disease (CVD), type 2 diabetes, metabolic syndrome, and skeletal disorders], as is low vitamin D status. No simple, reliable biomarker for whole-body magnesium status is currently available, which makes clinical assessment and interpretation of human magnesium research difficult. Between 1977 and 2012, US calcium intakes increased at a rate 2-2.5 times that of magnesium intakes, resulting in a dietary calcium to magnesium intake ratio of >3.0. Calcium to magnesium ratios <1.7 and >2.8 can be detrimental, and optimal ratios may be ∼2.0. Background calcium to magnesium ratios can affect studies of either mineral alone. For example, US studies (background Ca:Mg >3.0) showed benefits of high dietary or supplemental magnesium for CVD, whereas similar Chinese studies (background Ca:Mg <1.7) showed increased risks of CVD. Oral vitamin D is widely recommended in US age-sex groups with low dietary magnesium. Magnesium is a cofactor for vitamin D biosynthesis, transport, and activation; and vitamin D and magnesium studies both showed associations with several of the same chronic diseases. Research on possible magnesium and vitamin D interactions in these human diseases is currently rare. Increasing calcium to magnesium intake ratios, coupled with calcium and vitamin D supplementation coincident with suboptimal magnesium intakes, may have unknown health implications. Interactions of low magnesium status with calcium and vitamin D, especially during supplementation, require further study.

Keywords: calcium; calcium/magnesium ratio; essential mineral interactions; magnesium; nutrient interactions; vitamin D.

FIGURE 1

Mean magnesium intakes for US women (A) and men (B) from food alone (all adults) and from food plus supplements (supplement users only). Data are from the 2011–2012 NHANES (59) and DRIs (60). In US adults, 23% of women and 22% of men use dietary supplements that contain magnesium (59). EAR, Estimated Average Requirement.

FIGURE 2

Increasing calcium to magnesium ratios in US women (A) and men (B) from food alone (all adults) and from food plus supplements (supplement users only). Data are from the USDA Agricultural Research Service Food Surveys for 1977 and 1985 (63, 64), 1994–1995 (65), and 2001–2012 (, –70). In US adults, 23% of women and 22% of men use dietary supplements that contain magnesium (59). A calcium to magnesium ratio >2.8 interacts with a functional polymorphism in colorectal neoplasia risk (71).