This study investigates the relationship between dietary magnesium intake and brain structure, in particular brain volume size and the occurrence of white matter lesions (WML). The analysis is based on data from 6,001 adults aged 40 to 73 years from the UK Biobank.
The results show that a higher magnesium intake is associated with better brain health: people with a higher magnesium intake had larger amounts of gray and white matter as well as larger hippocampal volumes. At the same time, there were fewer white matter lesions, which are considered a risk factor for dementia. The positive effect was particularly pronounced in women, especially in postmenopausal women.
Interestingly, it was shown that not only the absolute magnesium intake is relevant, but also the long-term changes in magnesium intake. People who had permanently high magnesium levels had larger brain volumes than those with fluctuating or decreasing magnesium consumption. However, the expected blood pressure-lowering effect of magnesium could not be proven.
Conclusion: A diet rich in magnesium could help to maintain brain health and reduce the risk of dementia. Women in particular could benefit from a higher magnesium intake. Further studies are needed to clarify the exact mechanisms and long-term effects.
Background:
The global prevalence of dementia will increase dramatically in the coming decades. As there is currently no curative therapy, the focus is on preventive measures. Nutrition is a modifiable risk factor that could influence the progression of neurodegenerative diseases. Magnesium in particular is relevant for numerous physiological processes in the brain, including the reduction of oxidative stress, the regulation of neurotransmitters and the promotion of synapse function. Previous studies suggest that a higher magnesium intake could be associated with better cognitive performance and a lower risk of dementia. However, the exact point at which this effect becomes apparent is unclear.
Aims of the study:
This study examines:
- The relationship between magnesium intake and brain volume.
- The effects of magnesium on white matter lesions.
- The possible gender-specific differences in these effects.
- The influence of magnesium on blood pressure as a possible mediator for neuroprotective effects.
Methodology:
- Study population: 6,001 adults (40-73 years) from the UK Biobank.
- Survey of magnesium intake: Online nutrition questionnaire (24-hour recall).
- Imaging: Magnetic resonance imaging (MRI) to measure brain volumes and white matter lesions.
- Blood pressure measurement: Average of two measurements per person.
- Data analysis: Hierarchical linear models to study magnesium intake, brain structure and blood pressure.
Results:
Higher magnesium intake is associated with larger brain volume:
- Each 100 mg/day increase in magnesium intake was associated with an increase in gray matter (+0.001%), left hippocampus (+0.0013%) and right hippocampus (+0.0023%).
- The effect was more pronounced in women than in men.
Fewer white matter lesions with high magnesium intake:
- People with a high magnesium intake had significantly fewer WMLs than people with a low magnesium intake.
- This is particularly relevant as WMLs are considered a precursor to dementia and cognitive impairment.
Gender-specific differences:
- Women benefited more from a high magnesium intake than men.
- Postmenopausal women in particular had larger brain volumes and fewer WMLs with a high magnesium intake.
- However, women with a “decreasing” magnesium intake showed greater shrinkage of the brain structures than men with a comparable intake.
Long-term magnesium intake is crucial:
- People with a stable high magnesium intake over the years had the largest brain volumes.
- Low but increasing magnesium intake was associated with smaller brain volumes and more WMLs.
No significant correlation between magnesium and blood pressure:
- Magnesium was not significantly associated with a reduction in blood pressure.
- This indicates that the neuroprotective effects are not mediated via a reduction in blood pressure.
Discussion:
The study provides strong evidence that a high magnesium intake could slow down brain ageing. The clear gender difference is particularly noteworthy: women, especially postmenopausal women, benefited disproportionately from a high magnesium intake. This could be related to hormonal changes, as magnesium is also involved in oestrogen regulation.
Another key finding is that long-term magnesium intake patterns are more important than short-term changes. Stable magnesium intake over years was associated with the best results in terms of brain volume and WMLs.
An unexpected result was that magnesium did not correlate with a reduction in blood pressure. Although many studies classify magnesium as a blood pressure-lowering agent, this could play a subordinate role for neuroprotective effects. Instead, anti-inflammatory properties or an improvement in synaptic plasticity could be the decisive mechanisms.
Conclusion:
A high magnesium intake is associated with better brain health, especially with larger brain volumes and fewer white matter lesions. Women seem to benefit more from these effects, which suggests possible hormonal influences.
These results underline the importance of a magnesium-rich diet for the prevention of age-related brain diseases. Further long-term studies are needed to determine the optimal magnesium levels and the biological mechanisms behind these effects more precisely.