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Role of Magnesium in Type 2 Diabetes and Stroke

Oct 31, 2020
Editor: David L. Joffe, BSPharm, CDE, FACA

Author: Mia Flowers, PharmD. Candidate of Florida Agricultural & Mechanical University School of Pharmacy

Adequate amounts of magnesium in the diet could reduce type 2 diabetes and stroke / cerebral vascular incident risk.    

Magnesium plays a vital role in glucose metabolism, production of protein, and synthesis of nucleic acids. When magnesium levels are low in the body, it can contribute to many diseases, including cardiovascular diseases such as stroke, hypertension, insulin resistance, and type 2 diabetes mellitus. Most adults in developed countries do not get the recommended 310-420 mg daily amount of magnesium in their diet, although it could be consumed by eating green leafy vegetables, nuts, or whole grains. Previous studies have offered mixed opinions and insignificant findings with limited sample sizes and variation in the duration of interventions, populations, and study designs. Thus, the primary outcomes of this research were type 2 diabetes and stroke. A systematic review and meta-analysis of prospective cohort studies investigated the relationship between type 2 diabetes, cerebral vascular accidents, and the intake of specific magnesium doses.  

The trials were found on several sources, including ClinicalTrials.gov, Cochrane Library, Embase, PubMed, and the Web of Science. The search was conducted up until March 15, 2019, and the keywords of the investigation were “Cerebrovascular Stroke,” “Cohort Studies,” “Magnesium,” “Prospective Studies,” “Stroke,” “Type 2 Diabetes”, and “Type 2 Diabetes Mellitus.” Populations were deemed eligible if they had no previous history of insulin treatment or diabetes, and the patients could not have a current diagnosis of stroke. The patients had to have a prognosis that allowed for a minimum of a one year follow up. All studies had to include both dietary and supplemental intakes of magnesium. Studies were excluded if they were meta-analyses, basic science studies, focused only on supplementation of magnesium and involved gestational diabetes cases. Cardiovascular disease was excluded as a primary outcome due to the abundance of preexisting information on that topic.  Statistical analysis involved calculating absolute risk and relative risk with a 95% confidence interval to assess the risk associated with type 2 diabetes and stroke. The Newcastle-Ottawa Scale was used to assess methodological quality.  

A total of 53 cohorts were reviewed from 41 studies. There was a 22% reduction in risk for the patients with type 2 diabetes and 12% reduction for ischemic stroke (RR 0.88 (95% CI 0.81 to 0.95); p=0.001; AR reduction 0.246%) and 11% for total stroke (RR 0.89 (95% CI 0.83 to 0.94); p<0.001; AR reduction 0.281%) when conducting a comparison of the amounts of magnesium. The higher the magnesium, the lower the association. This relationship was found again in studies that involved an adjustment for fiber via cereal consumption in patients with type 2 diabetes (RR 0.79; p<0.001) and an adjustment for calcium in the total stroke population (RR 0.89; p=0.040). Analysis of subgroups presented the argument that females experienced a statistically significant decrease in the risk of ischemic and total stroke in addition to subjects with a BMI of 25 mg/m2or greater and patients who had a minimum 12 year follow up. It was noted that this trend was not as prevalent in Asian populations as it was in European and North American demographics.   

In totality, magnesium intake has a dose-dependent relationship that is inversely proportional to stroke and type 2 diabetes incidence. A reasonable recommendation for the prevention of these ailments could be a diet rich in magnesium. A limitation of this study was that the inclusion of randomized controlled trials did not prove it. Also, the frequency of food intake was limited by self-reporting on questionnaires. Some strengths were the number of prospective cohort studies examined, which allowed for a comprehensive analysis of quantitative data on magnesium intake. This data was used to identify the inverse relationship between type 2 diabetes mellitus, stroke, and magnesium intake and ultimately serve as a comprehensive update to clinical practice.  

Practice Pearls: 

  • Levels of magnesium should be periodically monitored in patients at an increased risk for cardiovascular disease or type 2 diabetes mellitus.  
  • Patients at risk of type 2 diabetes or stroke should make sure they receive the recommended daily amount of magnesium.  
  • Magnesium could help prevent or lessen cerebrovascular accidents, ischemic heart disease, and type 2 diabetes.  


Zhao, Binghao, et al. “Association of Magnesium Intake with Type 2 Diabetes and Total Stroke: An Updated Systematic Review and Meta-Analysis.” BMJ Open, vol. 10, no. 3, Mar. 2020, p. e032240, doi:10.1136/bmjopen-2019-032240.  


Mia Flowers, PharmD. Candidate of Florida Agricultural & Mechanical University School of Pharmacy