The Role of Magnesium for Cognitive Function in Older Adults

Taking advantage of this natural synergy is one way to maximize your vitamin D status, especially for improving brain elasticity and resisting COVID-19
BY Joseph Mercola TIMEJanuary 7, 2022 PRINT

The synergy between magnesium and vitamin D is critical 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.

Those findings are important, especially as the link between low vitamin D levels and various diseases, including severe COVID, continue to grow. In fact, people taking vitamin D, or doing what they can to raise their vitamin D levels, may not be getting the benefits they’re seeking because they are not also ensuring adequate magnesium intake.

Protecting Cognitive Health

One such study, “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 lower your risk for neurodegeneration as you grow older.

Magnesium, meanwhile, aside from being required for converting vitamin D to its active form, also plays a role in cognitive health. 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, the researchers reported.

“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,” they wrote.

Improved Brain Plasticity

While magnesium intake by itself didn’t 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, notes Dr. David Perlmutter, a neurologist and fellow of the American College of Nutrition.

“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,” he wrote in an article on his website.

A study published in Neuron in 2010 found a specific form of magnesium called magnesium threonate enhanced “learning abilities, working memory, and short- and long-term memory in rats.” 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.”

COVID’s Effect on the Brain

While we’re on the topic of the brain, a July 1, 2020, article in The Washington Post reviewed findings from autopsies of COVID-19 patients. Surprisingly, Chinese researchers had reported that COVID-19 patients can exhibit a range of neurological manifestations.

We now know COVID-19 patients report a host of neurological effects, from inability to taste or smell, to strokes, seizures, and delirium. Many report being confused or disoriented at discharge.

A previous COVID-19 infection is also associated with a new psychiatric diagnosis, which may be due to stroke due to blood clot in the brain, according to researchers in the United Kingdom, the Post reported.

The Post reported how Isaac Solomon, a neuropathologist at Brigham and Women’s Hospital in Boston, set out to investigate where the virus might be embedding itself in the brain using available data and anecdotal reports.

“He conducted autopsies of 18 consecutive deaths, taking slices of key areas: the cerebral cortex (the gray matter responsible for information processing), thalamus (modulates sensory inputs), basal ganglia (responsible for motor control) and others.”

Interestingly, while doctors and researchers initially suspected that brain inflammation was causing the neurological problems seen in some patients, Solomon’s autopsies found very little inflammation. Instead, these neurological manifestations appear to be the result of brain damage caused by oxygen deprivation.

Signs of oxygen deprivation were present both in patients who had spent a significant amount of time in intensive care, and those who died suddenly after a short but severe bout of illness. I believe this is likely due to increases in clotting in the brain microvasculature.

Solomon told The Washington Post he was “very surprised,” by the finding. It makes sense, though, considering COVID-19 patients have been found to be starved for oxygen. As reported by The Washington Post:

“When the brain does not get enough oxygen, individual neurons die … To a certain extent, people’s brains can compensate, but at some point, the damage is so extensive that different functions start to degrade … The findings underscore the importance of getting people on supplementary oxygen quickly to prevent irreversible damage.”

Magnesium and Vitamin D Impact Mortality

Getting back to magnesium and vitamin D, previous research using NHANES data from 2001 through 2006 found the duo has a positive impact on overall mortality rates. This study, published in BMC Medicine in 2013, also pointed out that magnesium “substantially reversed the resistance to vitamin D treatment in patients with magnesium-dependent vitamin-D-resistant rickets.”

The researchers hypothesized that magnesium supplementation increases your vitamin D level by activating more of it and that your mortality risk might therefore be lowered by increasing magnesium intake. That is indeed what they found. According to the authors:

“High intake of total, dietary or supplemental magnesium was independently associated with significantly reduced risks of vitamin D deficiency and insufficiency respectively.”

In other words, magnesium intake has a positive impact on vitamin D levels.  This also appears to have a role in disease formation, according to the study.

“The associations of serum 25(OH)D with mortality, particularly due to cardiovascular disease (CVD) and colorectal cancer, were modified by magnesium intake, and the inverse associations were primarily present among those with magnesium intake above the median.”

In plain language, the links between low 25(OH)D, an important form of vitamin D, and various health outcomes, including death, cardiovascular disease, and colorectal cancer, were reduced when people had higher magnesium levels. “Our preliminary findings indicate it is possible that magnesium intake alone or its interaction with vitamin D intake may contribute to vitamin D status. The associations between serum 25(OH)D and risk of mortality may be modified by the intake level of magnesium.”

Magnesium Lowers Vitamin D Requirement by 146 Percent

According to a scientific review published in 2018, as many as 50 percent of Americans taking vitamin D supplements may not get significant benefit as the vitamin D simply gets stored in its inactive form, and the reason for this is because they have insufficient magnesium levels.

GrassrootsHealth recently concluded you need 146 percent more vitamin D to achieve a blood level of 40 ng/ml (100 nmol/L) if you don’t take supplemental magnesium, compared to taking your vitamin D with at least 400 mg of magnesium per day.

The interplay between magnesium and vitamin D isn’t a one-way street, though. It goes both ways. Interestingly, while vitamin D improves magnesium absorption, taking large doses of vitamin D can also deplete magnesium. Again, the reason for that is because magnesium is required in the conversion of vitamin D into its active form.

Magnesium plus Vitamin K Lowers Vitamin D Requirement Even More

Magnesium isn’t the only nutrient that can have a significant impact on your vitamin D status. GrassrootsHealth data further reveal you can lower your oral vitamin D requirement dramatically simply by adding magnesium and vitamin K2. As reported by GrassrootsHealth:

“244 percent more supplemental vitamin D was needed for 50% of the population to achieve 40 ng/ml (100 nmol/L) for those not taking supplemental magnesium or vitamin K2 compared to those who usually took both supplemental magnesium and vitamin K2.”

How to Boost Your Magnesium Level

The recommended daily allowance for magnesium is around 310 mg to 420 mg per day depending on your age and sex, but many experts believe you may need anywhere from 600 mg to 900 mg per day.

Personally, I believe many may benefit from amounts as high as 1 to 2 grams (1,000 to 2,000 mg) of elemental magnesium per day, as most of us have EMF exposures that simply cannot be mitigated, and the extra magnesium may help lower the damage from that exposure.

My personal recommendation is that unless you have kidney disease and are on dialysis, continually increase your magnesium dose until you have loose stools and then cut it back. You want the highest dose you can tolerate and still have normal bowel movements.

When it comes to oral supplementation, my personal preference is magnesium threonate, as it appears to be the most efficient at penetrating cell membranes, including your mitochondria and blood-brain barrier. But I am also fond of magnesium malate, magnesium citrate, and ionic magnesium from molecular hydrogen as each tablet has 80 mg of elemental magnesium.

Eat More Magnesium-Rich Foods

Last but not least, while you may still need magnesium supplementation (due to denatured soils), it would certainly be wise to try to get as much magnesium from your diet as possible. Dark-green leafy vegetables lead the pack when it comes to magnesium content, and juicing your greens is an excellent way to boost your intake. Foods with high magnesium levels include:

  • Avocados
  • Swiss chard
  • Turnip greens
  • Beet greens
  • Herbs and spices such as coriander, chives, cumin seed, parsley, mustard seeds, fennel, basil and cloves
  • Broccoli
  • Brussel sprouts
  • Organic, raw grass-fed yogurt and natto
  • Bok Choy
  • Lettuce
Dr. Joseph Mercola is the founder of An osteopathic physician, best-selling author, and recipient of multiple awards in the field of natural health, his primary vision is to change the modern health paradigm by providing people with a valuable resource to help them take control of their health.
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