Although the underlying mechanisms for many of the pleiotropic effects of magnesium are not well understood, several pathways have been proposed to explain the beneficial effects of magnesium intake on metabolic disorders, including improvement of glucose and insulin homeostasis13 and lipid metabolism,14 as well as its antihypertensive,15 anti-inflammatory,6 and antioxidant functions.16 First, previous studies suggest that intracellular magnesium balance is important in maintaining peripheral glucose-mediated insulin action.17,18 Magnesium may preserve pancreatic β-cell function through its effects on cellular calcium homeostasis and/or oxidative stress.16 In fact, improvement in insulin sensitivity associated with increased magnesium intake has been reported in observational and clinical studies.19–21 Moreover, dietary magnesium intake was inversely correlated with fasting insulin level in diverse populations.22–25 Second, magnesium may affect lipid metabolism independent of its effects on insulin homeostasis. As a cofactor of many rate-limiting enzymes critical for lipid metabolism, magnesium has been shown to decrease low-density lipoprotein cholesterol and triglyceride levels and increase HDL cholesterol levels by inhibiting the activity of lecithin cholesterol acyl transferase26 and 3-hydroxy-3-methylglutaryl coenzyme A reductase, and stimulating lipoprotein lipase activity.27 The potential beneficial effects of magnesium on lipid metabolism have been supported by animal,14,28 epidemiologic,9,23 and clinical studies.26 Third, it has been suggested that magnesium has multiple functions critical for its antihypertensive effects, such as the inhibition of intracellular calcium mobilization as a calcium antagonist;15,29 attenuation of the adverse effect of sodium by stimulating activity of Na—K ATPase or increasing urinary excretion of sodium;15 decreased release of catecholamines;15,29 and improvement of myocardial contractility,29,30 systemic inflammation,6 and endothelium-dependent vasodilation.31,32 Data from experimental and observational studies on magnesium and blood pressure have been summarized elsewhere.15 Since the previous findings were not consistent, a meta-analysis pooled 20 randomized clinical trials including 1220 individuals and found a significant inverse association between magnesium supplementation and blood pressure.33 Fourth, in He et al,8 magnesium intake was inversely related to waist circumference. The mechanism for a possible beneficial effect of magnesium intake on body weight is, however, unknown. It has been suggested that magnesium may be involved in forming soaps with fatty acids in the intestine and may reduce the digestible energy content of the diet.34 Thus, magnesium intake may benefit weight maintenance. Further studies are warranted to better understand magnesium intake in relation to body weight.