NEW YORK (Reuters Health) – Pregnancy outcomes among women with gestational diabetes are similar whether they follow a low-glycemic index (LGI) diet or a conventional high-fiber diet, according to an Australian study reported in Diabetes Care online September 6.

Still, the authors conclude, “An LGI diet appears to be a safe alternative to the traditional pregnancy diet for women with GDM (gestational diabetes mellitus) and expands the range of dietary strategies that can be offered.”

Dr. Jennie Brand-Miller, at the University of Sydney, and colleagues point out that low-glycemic index foods reduce postprandial glucose in healthy individuals and could represent a way to do the same in gestational diabetes without restricting carbohydrate. This might reduce excessive birth weights.

To investigate, they conducted a randomized controlled trial in 99 women diagnosed with gestational diabetes at 20-32 weeks’ gestation. The participants were assigned to one of two healthy diets containing similar proportions of protein, fat, and carbohydrate – but one with a low glycemic index (target GI <50) and the other with a high-fiber (HF) content and moderate GI (target GI ~60).

Fewer women gained excessive weight on the LGI diet (25%) than the HF diet (42%), and fewer needed insulin treatment (53% vs 61%), the team found.

However, neonatal outcomes were virtually the same in both groups. Mean birth weight in both arms was 3.3 kg (p=0.619), the rate of macrosomia was 2.1% with the LGI diet compared to 6.7% on the HF diet (p=0.286), and the ponderal index was 27.2 versus 27.0 kg/meter cubed (p=0.614) in the two groups, respectively, Dr. Brand-Miller and colleagues report.

“Contrary to our hypothesis,” they conclude, “this randomized controlled trial of an LGI diet versus a conventional high-fiber diet found no differences in key pregnancy outcomes in GDM.”

They add, “Further studies in overweight and obese individuals and earlier interventions in women with risk factors for GDM are warranted.”

Reference:
Randomized Controlled Trial Investigating the Effects of a Low–Glycemic Index Diet on Pregnancy Outcomes in Gestational Diabetes Mellitus
Diabetes Care 2011.