The effects of magnesium-zinc-calcium-vitamin D co-supplementation on biomarkers of inflammation, oxidative stress and pregnancy outcomes in gestational diabetes

Randomized, placebo-controlled, single-center trial in pregnant women with gestational diabetes mellitus who were not using oral hypoglycemic agents. For the active magnesium-zinc-calcium-vitamin D group, 30 participants were randomized and 30 completed the trial; the study was conducted at Kosar Clinic, Arak, Iran, from March to November 2017.

The active intervention was an oral magnesium-zinc-calcium-vitamin D tablet taken twice daily for 6 weeks. Each dose contained magnesium 100 mg, zinc 4 mg, calcium 400 mg, and vitamin D 200 IU; participants in the comparison arm received placebo.

Six weeks of magnesium-zinc-calcium-vitamin D co-supplementation improved several inflammation and oxidative stress markers in women with gestational diabetes. In the active arm, hs-CRP decreased from 6.9 ± 1.7 to 5.7 ± 3.7 mg/L (P = 0.01), TAC increased from 619.4 ± 81.1 to 657.6 ± 98.1 mmol/L (P = 0.01), and MDA decreased from 2.9 ± 0.3 to 2.6 ± 0.2 μmol/L (P = 0.003), while total nitrite did not change significantly (43.1 ± 5.5 to 44.3 ± 6.1 μmol/L; P = 0.76) and GSH was not significant (P = 0.32). Nutrient biomarkers also rose, including 25-OH-vitamin D from 12.6 ± 4.2 to 18.7 ± 4.7 ng/mL (P = 0.001), and there were favorable pregnancy trends with higher newborn weight (3089.8 ± 519.9 g vs 3346.3 ± 411.1 g; P = 0.05) and lower macrosomia (3.3% vs 16.7%; P = 0.08).

The trial was small, single-center, and short in duration (6 weeks), which limits confidence in clinical outcomes. The intervention combined four supplements, so the effect of any single nutrient cannot be isolated, and some pregnancy outcome findings were only trends rather than statistically definitive results.