Magnesium: Health Effects, Deficiency Burden, and Future Public Health Directions.

Magnesium (Mg2+) is the fourth most abundant cation in the human body and a critical cofactor in hundreds of enzymatic reactions that regulate energy metabolism, neuromuscular function, cardiovascular health, bone integrity, immune defense, and psychological well-being. Despite its essential roles, magnesium deficiency remains common worldwide, driven by inadequate dietary intake, chronic diseases, medication use, and lifestyle factors. Low magnesium status is associated with hypertension, type 2 diabetes, osteoporosis, migraines, depression, and chronic inflammation, whereas sufficient intake supports cardiometabolic resilience, skeletal strength, neurological stability, and healthy aging. This review synthesizes current evidence on magnesium metabolism, physiological functions, and the health consequences of deficiency, and it summarizes global status with attention to biomarker limitations, widespread suboptimal intake, and key demographic and lifestyle determinants. It also discusses dietary sources, supplementation, and innovative approaches such as food fortification, personalized nutrition, and improved diagnostic strategies. The evidence highlights magnesium as a modifiable factor with potential to lessen the burden of chronic diseases. Recognizing magnesium deficiency as a pressing but underappreciated public health issue, this article underscores the need for integrated strategies to optimize magnesium balance at both individual and population levels.