Magnesium's Effect on Bone Health: A Nutritional Intervention Study.

摘要

Osteoporosis is a major health issue in the United States. It is a progressive bone disease resulting from an imbalance between bone resorption by osteoclasts and bone formation by osteoblasts, leading to decreases in bone mineral density and an increase in fracture risk. Approximately 10 million adults have been diagnosed with osteoporosis, while an estimated 44 million have low bone mass (2). It has been estimated that 2 million fractures yearly are attributed to osteoporosis, which amounts to about ;The exact pathogenesis of osteoporosis has yet to be defined. It is thought that the cause of this disease is multi-factorial and is influenced by genetic factors, gender, race, lifestyle, and diet (25, 26, 31, 34, 35). Recent evidence suggests that changes in diet and lifestyle are successful strategies in aiding in the prevention and progression of osteoporosis (34, 35). Most research relating diet to bone health has involved the roles of calcium, vitamin D, and their synergistic activity, however, other nutrients have shown to also play a pivotal role.;An example of a mineral that is in need of additional examination relative to its role in bone health is magnesium. Magnesium is the fourth most abundant mineral in the body, 60% of which is stored in bone (59). Although this mineral is found in a variety of foods including grains, nuts, cereals, legumes, green leafy vegetables, dairy, etc., various dietary intake studies suggest that most Americans are not fulfilling their magnesium requirement (57, 58).;Interestingly, magnesium has shown to play a role in bone metabolism by affecting the activity of factors involved in bone formation and resorption (70, 71). Magnesium helps in the stabilization of alkaline phosphatase (ACP), which allows for more properly formed bone crystals (75). It also influences calcium metabolism and regulates various hormones including parathyroid hormone and calcitriol, the active form of vitamin D (81-83).;In the present study, associations between magnesium and bone health were investigated in twelve postmenopausal women in a randomized controlled trial. Subjects received a labeling dose of 100nCi 41Ca and started a 180 day equilibration period for the isotope to stabilize in the skeleton followed by three 6-week phases, which included a calcium/vitamin D supplementation period and a dairy period in a cross-over method, with a six week wash-out period in between. Both interventions demonstrated positive effects on bone metabolism, as seen through examination of bone alkaline phosphatase (BAP) (bone formation marker), carboxy-terminal collagen crosslinks (CTx) (bone resorption marker), and the ratio of 41Ca/40Ca. Although no significant associations were seen between magnesium and bone health, there were positive associations between skeletal formation and other nutrients, specifically zinc. The findings from this study are novel in that they further solidify the idea that dairy positively impacts bone health more than calcium and vitamin D supplements alone. It is thought that this is due to the additional nutrients dairy provides, however, the exact mechanisms for each nutrient have yet to be defined.