Association between dietary magnesium intake and muscle mass among hypertensive population: evidence from the National Health and Nutrition Examination Survey.

Background: Magnesium is critical for musculoskeletal health. Hypertensive patients are at high risk for magnesium deficiency and muscle loss. This study aimed to explore the association between magnesium intake and muscle mass in patients with hypertension.

Methods: In this population-based cross-sectional study, 10,279 U.S. hypertensive adults aged 20 years or older were derived from the National Health and Nutrition Examination Survey in 1999-2006 and 2011-2018. Magnesium (Mg) intake from diet and supplements was assessed using 24-hour diet recalls. Muscle mass was evaluated by appendicular skeletal muscle mass index (ASMI, total ASM in kilograms [kg] divided by square of height in meters [m²]). The association of Mg intake with ASMI was estimated using weighted multivariable-adjusted linear regression models and restricted cubic splines.

Results: Dose-response analyses showed a positive linear correlation between dietary Mg intake and ASMI. Every additional 100 mg/day in dietary Mg was associated with 0.04 kg/m² (95% confidence interval [CI] 0.02-0.06 kg/m²) higher ASMI. The ASMI in participants who met the recommended dietary allowance (RDA) for dietary Mg was 0.10 kg/m² (95% CI 0.04-0.16 kg/m²) higher than those whose dietary Mg was below estimated average requirement (EAR). However, the relationship of Mg intake from supplements with ASMI was not identified.

Conclusion: Higher level of dietary Mg intake rather than Mg supplements was associated with more muscle mass in U.S. adults with hypertension, which highlights the importance of meeting the recommended levels for dietary Mg intake.