A carefully controlled trial found that magnesium may lower fasting blood sugar levels in older adults with magnesium deficiency, but fixing a single mineral may not be enough to stop diabetes progression.
study: Oral magnesium supplementation improves glycemic control in Chinese elderly with prediabetes and hypomagnesemia: a randomized controlled trial. Image credit: Pixel-Shot/Shutterstock.com
Prediabetes is a condition characterized by elevated blood sugar levels, but not at diabetic levels. Recent research published in journals Frontiers of nutrition We are investigating whether magnesium supplementation in prediabetic patients, particularly older adults with hypomagnesemia, can improve glycemic control.
Magnesium deficiency emerges as a modifiable risk factor
Prediabetes, a condition in which blood sugar levels are elevated but not yet in the diabetic range, is an important window for intervention. Without treatment, prediabetes can progress to type 2 diabetes. To prevent such outcomes, it is important to design and test effective community-friendly approaches.
One potential target is magnesium status. Magnesium deficiency is relatively common, especially among the elderly, and is associated with impaired glucose metabolism and insulin resistance. Biologically, magnesium is a cofactor for multiple enzymes that regulate glucose metabolism and insulin signaling.
There are only two randomized controlled trials (RCTs) has been conducted to evaluate the effects of magnesium supplementation in prediabetic patients. Both trials were small and did not select participants based on magnesium deficiency or closely track dietary magnesium intake, which may explain the mixed results.
Older people are more likely to develop prediabetes and magnesium deficiency because nutrient absorption decreases with age. Therefore, the present study targeted this population.
Tested 360 mg of Magnesium Oxide daily
Researchers conducted an exploratory experiment RCT The study was conducted over 16 weeks on 71 elderly Chinese adults (average age 69 years) with prediabetes and magnesium deficiency. They were randomly assigned to receive magnesium oxide supplements (360 mg elemental magnesium per day, taken once daily with a meal) or a placebo. Of these, 65 completed the study.
The primary endpoint was change in fasting plasma glucose (FPGAdditionally, the researchers evaluated insulin levels, C-peptide, and insulin resistance using a homeostasis model assessment of insulin resistance (homer il), often used as a surrogate for hepatic insulin resistance. They also measured glycated hemoglobin (HbA1c), glycated albumin, and high-sensitivity C-reactive protein (hs-CRP) and interleukin 6 (IL-6).
Serum magnesium increases due to moderate changes in blood sugar.
Dietary magnesium intake was similar in both groups, but baseline calcium intake was higher in the magnesium group. This group also had higher baseline insulin; homer il level. We adjusted for these differences in our analyses.
Magnesium supplementation increased magnesium to a greater extent than placebo. The adjusted mean difference was 0.056 mmol/L.
Fasting blood glucose levels also decreased slightly in the magnesium group, with an adjusted mean difference of -0.5 mmol/L. Other measures include: HbA1cthere was no significant difference. This suggests that the reduction in fasting blood glucose levels was not translated into evidence of sustained overall glycemic improvement over 16 weeks.
The improvement in fasting blood sugar is consistent with previous studies using similar samples, but another study had conflicting results. The authors emphasize the basic premise of the current study. In other words, magnesium supplementation is associated with significant improvements in glucose metabolism only in patients with hypomagnesemia.
Of note, almost 92% of subjects reported compliance with the intervention protocol, and dietary intake did not change over the study period. This increases confidence in the observation results. The intervention was well tolerated, and no intervention-related adverse events were reported. The small effect size, combined with the lack of change in markers such as glycated hemoglobin, reduces clinical relevance, especially in the long term.
A preliminary metabolomics array shows that magnesium supplementation is associated with changes in 52 metabolites. Metabolomics is a technique that measures small molecules in the blood to provide a snapshot of metabolic processes. These were associated with lipid metabolism and insulin resistance. However, given the nature of this analysis and the fact that the identity of the metabolites is speculative and based on mass spectrometry annotations, this is only a hypothesis-generating study.
Well-controlled designs but underpowered samples
Strengths of this study include the intervention; RCT design, monitoring of dietary magnesium during the study period, and use of metabolomics to reflect non-glycemic changes associated with magnesium supplementation.
Despite these benefits, several limitations make these findings strictly hypothesis-generating rather than confident claims about clinically meaningful improvements in glycemic status with magnesium supplementation. The small sample size meant that the study was underpowered for most outcomes. Uses only fasting blood glucose levels rather than dynamic blood glucose markers such as postprandial blood glucose levels or oral glucose tolerance tests (Oguto), some of the effects of the intervention on glucose metabolism may be omitted.
Baseline differences in insulin and insulin resistance between groups may have caused residual confounding. The effect size was small, and the relatively low bioavailability of magnesium oxide may also have limited the physiological effects of the supplement.
Magnesium oxide has relatively low bioavailability compared to citrate and glycinate. This may have reduced the physiological effects of magnesium supplementation by limiting the amount of ionized or intracellular magnesium available to the body. Future studies should compare different formulations to confirm this and derive dose-response relationships.
Larger and longer trials are needed for clarity
In Chinese elderly with prediabetes and magnesium deficiency, magnesium supplementation was effective in significantly increasing serum magnesium concentrations, correcting magnesium deficiency, and reducing fasting blood glucose concentrations at the group level. On the other hand, “the overall evidence for strong, multifaceted improvements in glucose metabolism from this single study is limited.”
Future studies should confirm these findings, especially the clinical relevance of lowering fasting blood glucose levels alone. This will require larger trials with longer follow-up periods.