Higher magnesium intake linked to lower dementia risk

For the study, the researchers included healthcare data from 6,001 participants aged 40–73 years old from the UK Biobank.

Data included blood pressure measurements, a magnetic resonance imaging (MRI) scan, and dietary magnesium intake over a 24-hour period five times over 16 months.

Over 95% of participants consumed stable amounts of magnesium over the study period. Some, however, increased their intake over time, while others decreased their intake.

In the end, they found that higher dietary magnesium intake was linked to larger brain volumes and smaller white matter lesions (WML)—both of which are indicators of dementia—in MRI scans.

They also found that consuming over 550 mg of magnesium daily is linked to a roughly one-year younger brain age by 55 years old than consuming 350 mg per day, which is close to the average daily intake.

This, they noted, means that increasing magnesium intake by 41% could improve brain health, preserve cognitive ability, and lower dementia risk.

They further found that high dietary magnesium intake was more neuroprotective for women than men, and post-menopausal women compared to premenopausal women.

However, they noted that the decreasing magnesium consumption over time was linked to larger brain volumes in women.

Links between magnesium intake and blood pressure measures were mostly non-significant.

“It’s known that magnesium is a neuroprotector as well as it having positive effects on blood pressure,” Dr. Howard Pratt, D.O., psychiatrist and Behavioral Health Medical Director at Community Health of South Florida, Inc., who was not involved in the study, told MNT.

“High blood pressure in and of itself is a known risk factor for dementia. Increasing dietary intake of magnesium can have positive effects on cardiovascular health with the study subsequently showing a decrease in white matter lesions in middle to early old age,” he added.

Dr. Johnson-Arbor noted that magnesium might help reduce inflammation.

“As we age, we are likely to develop chronic medical conditions, such as kidney disease and vitamin D deficiency, that cause magnesium deficiency. Because magnesium deficiency may lead to decreased cellular messaging and enhanced inflammation within the brain, some studies have suggested that magnesium may be involved in the development of dementia and other neurologic conditions.”
— Dr. Johnson-Arbor

MNT spoke to Dr. Bruce Albala, professor of environmental & occupational health at the University of California, Irvine, Program in Public Health, who was also not involved in the study, to understand what might explain the increased effects of magnesium on post-menopausal women.

“The authors propose that the higher magnesium intake might have resulted in less chronic inflammation in these older women. These results should be viewed as preliminary at this time, especially for the smaller magnesium dietary subgroups,” he said.

“One of the interesting things about estrogen is that it is a vasodilator meaning that it can help lower blood pressure, and post-menopausal women having lower estrogen levels can in fact result in higher blood pressure. This is evidenced by the increase in cardiovascular risks for heart attack in women after menopause.”
— Dr. Howard Pratt

Dr. Johnson-Arbor further noted that the difference might be linked to health conditions that occur at different rates in men and women that may impact the clinical effects of magnesium. She said, however, that the authors did not study the impacts of other health conditions.

Dr. Albala noted that the study has several limitations. As the researchers did not include a follow-up MRI scan, it remains to be seen whether magnesium is protective later in life as the participants’ average age was 55 years old.

He added that as over 95% of participants had stable magnesium intake over 16 months, they had very little data on how changing magnesium intake over time affects dementia risk.

He further said that magnesium consumption does not necessarily correlate with actual magnesium levels in the body nor how it impacts tissues such as the brain.

Dr. Pratt added that the study investigated risk factors as opposed to dementia diagnoses.

“The thing that limits this study is that a person can have several risk factors for dementia but may never develop it. There are also limitations in the lack of understanding of when and to what extent magnesium exerts its neuroprotective effects on the brain,” he noted.

“Although the study authors took into account factors such as cholesterol levels, history of tobacco use, history of diabetes, physical activity, and alcohol intake when they created their analysis, they did not collect information on other conditions—such as other cancer, kidney disease, or other neurologic conditions—that may have impacted the findings in this study,” Dr. Johnson-Arbor further explained.

MNT spoke with Dr. Naomi Jean-Baptiste, a board-certified emergency medicine physician, who was not involved in the study, about the study’s implications. She warned against taking too much magnesium.

“Like all nutrients in the body, there is an ideal range and too much magnesium can be harmful to your body. High levels of magnesium can cause muscle weakness, fatigue, low blood pressure, breathlessness, and even death. So, you must be careful and discuss with your doctor before adding more magnesium to your diet.”
— Dr. Naomi Jean-Baptiste

MNT also spoke with Dr. Jason Krellman, neuropsychologist and assistant professor of neuropsychology at Columbia University Medical Center, who was also not involved in the study, about the findings.

“Further research using highly controlled, experimental conditions and a study design that tracks people’s neurocognitive health over time is needed to study the potential neurological and cognitive benefits of a magnesium-rich diet,” he said.

“However, the study’s promising findings highlight that there are several risk factors for dementia that individuals can identify and reduce through healthy lifestyle choices, including heart-healthy eating habits, aerobic exercise as tolerated, and doing cognitively and socially stimulating activities that you enjoy.”