Dietary magnesium intake is related to larger brain volumes and lower white matter lesions with notable sex differences.
Level 3 - non-randomized controlled study
Prospective/longitudinal observational cohort study assessing dietary intake and neuroimaging outcomes
PubMed 36899275 · doi:10.1007/s00394-023-03123-x
What was done
Researchers evaluated 6,001 participants (aged 40–73 years) from the UK Biobank to assess the relationship between dietary magnesium intake, brain volumes, and white matter lesions (WMLs). Dietary magnesium intake was estimated using online computerized 24-hour recall questionnaires. Latent class analysis identified magnesium intake trajectory groups, and hierarchical linear regression models adjusted for health and socio-demographic covariates to evaluate associations with gray matter, white matter, hippocampal volumes, and WMLs. The authors also tested for blood pressure mediation and interactions with menopausal status.
What was found
Higher baseline dietary magnesium intake was associated with slightly larger brain volumes across both sexes: gray matter increased by 0.001% (SE = 0.0003), left hippocampus by 0.0013% (SE = 0.0006), and right hippocampus by 0.0023% (SE = 0.0006). Latent class analysis categorized participants into stable normal (95.71% men, 96.51% women), high-decreasing (3.2% men, 1.9% women), and low-increasing (1.09% men, 1.62% women). In women, the high-decreasing trajectory was associated with larger gray matter (1.17%, SE = 0.58) and right hippocampal volume (2.79%, SE = 1.11) compared to the stable normal group, with stronger associations in post-menopausal women. The low-increasing trajectory in women was linked to smaller gray matter (-1.67%, SE = 0.30), white matter (-0.85%, SE = 0.42), left hippocampus (-2.43%, SE = 0.59), right hippocampus (-1.50%, SE = 0.57), and larger WMLs (1.6%, SE = 0.53). Magnesium associations with blood pressure were mostly non-significant.
Why it matters
The findings suggest a potential neuroprotective association between higher dietary magnesium intake and structural brain preservation in mid-to-late life, with more pronounced associations observed in post-menopausal women.
Limits
Dietary intake was based on self-reported 24-hour recall questionnaires, which are vulnerable to recall bias and day-to-day intake variability. The trajectory groups showing the largest volume differences comprised less than 5% of the total sample, limiting statistical power in those subgroups. Due to the observational design, residual confounding cannot be ruled out, and causality cannot be established. UK Biobank participants also tend to be healthier and wealthier than the general population.
Cited by
- supports Insufficient magnesium levels are linked to accelerated brain volume loss and earlier onset of dementia.
- supports In a UK Biobank study of over 6,000 participants aged 40 to 73, higher dietary magnesium intake (~550 mg/day vs ~350 mg/day) was associated with larger gray matter and hippocampal volumes, equivalent to approximately one year of reduced brain aging.