Epigallocatechin gallate (EGCG), a natural compound found in green tea extract, has demonstrated beneficial effects on insulin secretion and insulin sensitivity in animal studies.
In a randomised, placebo-controlled trial, researchers evaluated the effects of EGCG supplementation on maternal symptoms and neonatal outcomes in women with gestational diabetes.
A total of 404 women with gestational diabetes were randomised to take 500 mg of EGCG per day or a placebo from the beginning of the third trimester until full term.
From baseline to full term, those taking EGCG had significant reductions in fasting plasma glucose (105 mg/dL at baseline vs 89 mg/dL at full term), significant reductions in insulin levels (16 µIU/mL at baseline vs 9 µ/mL at full term), significant decreases in HOMA-IR (3.8 at baseline vs 2.0 at full term), significant decreases in HOMA-ß [a meaure of insulin resistance] (57 at baseline vs 45 at full term), and significant improvements on the QUICKI score of diabetic symptoms.
In contrast, those taking placebo experienced no change in fasting plasma glucose, a significant increase in insulin levels, no change in HOMA-IR or HOMA-ß, and no significant change in QUICKI score from baseline to full term.
When compared with the placebo, women taking EGCG had significantly lower levels of fasting plasma glucose, insulin, HOMA-IR and HOMA-ß at full term.
During the course of the study, 57 women withdrew to start insulin therapy for uncontrolled blood glucose levels.
Of these 57 women, 16 (8% of the 202 participants) were from the EGCG group and 41 (20% of the 202 participants) were from the placebo.
Incidence of low birth weight and neonatal hypoglycaemia were significantly reduced in the EGCG group, and the 1-minute and 5-minute Apgar scores were significantly higher in the EGCG group when compared with the placebo.
The authors conclude that EGCG supplementation improves maternal and neonatal outcomes of gestational diabetes.
