A higher intake of magnesium in diet is associated with reduced risk of dementia. This effect was more pronounced in women than in men, suggests a study published March 10, 2023 in the European Journal of Nutrition.¹

In this study, researchers from the Australian National University in Canberra, Australia investigated the association between magnesium in diet and brain volumes and white matter lesions. A total of healthy 6001 participants, aged 40-73 years (mean age, 55.3 years), were recruited from the UK Biobank study from 2005 to 2023. A 24-hour recall questionnaire was used to assess the daily dietary magnesium intake especially through the consumption of foods like leafy green vegetables, legumes, nuts, seeds and whole grains.

Overall, participants with higher baseline intake of dietary magnesium were found to have larger brain volumes; gray matter 0.001%, left hippocampus 0.0013% and right hippocampus 0.0023% and smaller white matter lesions as seen on MRI scans.

During the course of the study, some participants were observed to decrease their intake of magnesium, few increased their consumption, while the majority continued with a stable amount of magnesium. Three classes of magnesium intake were defined and estimated separately for men and women: high-decreasing (men = 3.2%, women = 1.9%), low-increasing (men = 1.09%, women = 1.62%) and stable normal (men = 95.71%, women = 96.51%). 

Participants in the high-decreasing category had larger brain volumes compared to those in the normal-stable group. However, this association was more significant in women with a 1.17% larger GM, and 2.79% larger RHC than in men. Among women, the effect was more marked in the postmenopausal women vs premenopausal women. Similarly, participants in the low-increasing group had smaller brain volumes compared to those in the normal-stable group. Again, this association was more significant in women than in men with − 1.67% smaller GM, − 0.85% smaller WM, − 2.43% smaller LHC, − 1.50% smaller RHC, and 1.6% larger WMLs.

A daily intake of more than 550 mg of magnesium was associated with a younger brain age compared to 350 mg every day. The researchers noted that “a 41% increase in Mg intake may lead to significantly better brain health, which would also be expected to contribute to greater preservation of cognitive ability, and lower risk or delayed onset of dementia in later life”.

The study also examined the association between magnesium intake and BP and found it to be nonsignificant. This indicates that the neuroprotective effect of magnesium was mediated via its effect on BP.

This study highlights the benefits of a diet containing high amounts of magnesium (≥ 550 mg/day vs normal intake of (~ 350 mg/day) in maintaining a healthy brain, especially in women. The underlying mechanism for this protective effect has been hypothesized to be the anti-inflammatory effect of magnesium, which decreases the pro-inflammatory cytokines such as interleukin 1 beta (IL-1β), IL-6 and Tumor Necrosis Factor (TNF) and increases neurogenesis. Since dementia is an incurable condition, prevention is the key. Hence, diet may be a potentially modifiable risk factor for dementia.

The daily recommended dietary allowances (RDA) for magnesium are 420 mg for men and 320 g for women in the age group 31-50 years and ≥51 years. Green leafy vegetables, such as spinach, legumes, black beans, kidney beans, nuts (almonds, cashew, peanuts), seeds (pumpkin seeds, chia seeds) and whole grains (whole wheat, quinoa), avocado, tofu, banana, soy milk are good sources of magnesium.2

References

1. Alateeq K, et al. Dietary magnesium intake is related to larger brain volumes and lower white matter lesions with notable sex differences. Eur J Nutr. 2023 Mar 10. doi: 10.1007/s00394-023-03123-x.
2. Magnesium Fact Sheet. Available at: https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/#h3. Accessed on April 1, 2023.