Magnesium supplementation modulates T-cell function in people with type 2 diabetes and low serum magnesium levels

CONTEXT: Low magnesium levels, which are common in people with type 2 diabetes, are associated with increased levels of pro-inflammatory molecules. It is unknown whether magnesium supplementation decreases this low-grade inflammation in people with type 2 diabetes. OBJECTIVE: We performed a multidimensional immunophenotyping to better understand the effect of magnesium supplementation on the immune system of people with type 2 diabetes and low magnesium levels. METHODS: Using a randomized, double-blind, placebo-controlled, two-period, cross-over study, we compared the effect of magnesium supplementation (15 mmol/day) to placebo on the immunophenotype including whole blood immune cell counts, T-cell and CD14+ monocyte function after ex vivo stimulation, and the circulating inflammatory proteome. RESULTS: We included 12 adults with insulin-treated type 2 diabetes (7 males, mean±SD age 67±7 years, BMI 31±5 kg/m2, HbA1c 7.5±0.9 %) and low magnesium levels (0.73±0.05 mmol/l). Magnesium treatment significantly increased serum magnesium and the urinary magnesium excretion, when compared to placebo. The IFN-? production from PMA/ionomycin stimulated CD8+ T-cells and T-helper 1 cells, as well as the IL4/IL5/IL13 production from T-helper 2 cells was lower after treatment with magnesium compared to placebo. Magnesium supplementation did not affect immune cell numbers, ex vivo monocyte function and circulating inflammatory proteins, although we found a tendency for lower high sensitive CRP levels after magnesium supplementation compared to placebo. CONCLUSIONS: In conclusion, magnesium supplementation modulates the function of CD4+ and CD8+ T-cells in people with type 2 diabetes and low serum magnesium levels.