I've previously discussed the synergy between magnesium and vitamin D, and the importance of vitamin D for optimal immune function and overall health — especially as it pertains to lowering your risk of COVID-19. Previous studies have also highlighted the role this duo plays in cognitive function among older adults, as well as overall mortality.
Vitamin D and Magnesium Protect Cognitive Health
One such study,1 "Association of Vitamin D and Magnesium Status with Cognitive Function in Older Adults: Results from the National Health and Nutrition Examination Survey (NHANES) 2011 to 2014," points out that vitamin D not only protects neuronal structures and plays a role in neuronal calcium regulation, but also appears to impact your risk for neurodegeneration as you grow older.
Magnesium, meanwhile, aside from being required for converting vitamin D to its active form,2,3,4 also plays a role in cognitive health, and magnesium deficiency has been implicated in several neurological disorders.
Using NHANES data from 2,984 participants over the age of 60, the researchers compared serum vitamin D status and dietary magnesium intake against cognitive function scores.
After adjusting for confounding factors, including total calorie consumption and magnesium intake, higher blood levels of vitamin D positively correlated with decreased odds of having a low cognitive function score on the Digit Symbol Substitution Test.
The same trend was found when they looked at vitamin D intake, rather than blood level. The correlation of higher vitamin D levels and better cognitive function was particularly strong among those whose magnesium intake was equal to or greater than 375 mg per day. According to the authors:5
"We found that higher serum 25(OH)D levels were associated with reduced risk of low cognitive function in older adults, and this association appeared to be modified by the intake level of magnesium."
Magnesium Improves Brain Plasticity
While magnesium intake by itself did not appear to have an impact on cognitive function in the study above, other research has highlighted its role in healthy cognition.
Memory impairment occurs when the connections (synapses) between brain cells diminish. While many factors can come into play, magnesium is an important one. As noted by Dr. David Perlmutter, a neurologist and fellow of the American College of Nutrition:6
"It has now been discovered that magnesium is a critical player in the activation of nerve channels that are involved in synaptic plasticity. That means that magnesium is critical for the physiological events that are fundamental to the processes of learning and memory."
A specific form of magnesium called magnesium threonate was in 2010 found to enhance "learning abilities, working memory, and short- and long-term memory in rats."7 According to the authors, "Our findings suggest that an increase in brain magnesium enhances both short-term synaptic facilitation and long-term potentiation and improves learning and memory functions."