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Dietary Changes and Gestational Diabetes Mellitus

Mar 20, 2015

An increase in polyunsaturated fatty acid intake showed some benefit in pregnant women with GDM as well as the fetus…

GDM not only puts mothers at risk but it can also be dangerous for infants. Studies show that more than half of pregnant women with GDM develop overt diabetes within the next 20 years, and their offspring are also at risk for obesity and diabetes. Research in the last decade shows that an inappropriate diet during pregnancy increases the risk of GDM. Also, data shows that reduced dietary intake of polyunsaturated fatty acids (PUFA), and increased high fat, high saturated fatty acid (SFA) is an independent risk factor for GDM.


Researchers from Nanjing Medical University, China studied the impact of increasing polyunsaturated fatty acid intake on blood glucose, lipid metabolism, and pregnancy outcomes of pregnant women with gestational diabetes mellitus with this diet.

Participants were pregnant women with GDM diagnosed in the obstetric clinics of Changzhou MCH Hospital from January 2011 to January 2013. The patients were aged 22-38 years and 24-28 weeks pregnant. None of the participants were associated with pregnancy related complications and there were no reported history of diabetes, hypertension or GDM. The diagnostic criteria for GDM was a 75 g oral glucose tolerance test (OGTT) performed at 24-28 weeks of pregnancy. Glucose levels after fasting, and 1 and 2 hours after glucose administration <91.8 mg/dL, <180 mg/dL, and <153 mg/dL, respectively, were considered normal; if the glucose level exceeded the standard at any point, the patient was diagnosed as GDM. While under constant total energy and protein intake, 84 pregnant women with GDM were randomly divided into the experimental and control groups 41 and 43 patients, which were then given oil-rich and conventional low-oil meals, respectively.

After the diagnosis of GDM, a nutritionist provided individualized dietary guidance. Total daily calories were calculated according to the patient’s height, weight, gestational weeks, and physical strength. Total caloric intake of a light physical worker in late pregnancy was calculated by: ideal weight × 30 kcal/kg· day + 200 kcal.

Results showed that after dietary intervention, the intake and energy supply of fat and the three fatty acids were significantly higher in the experimental group than the control group (P <0.001). The intake and energy supply of polyunsaturated fatty acids increased significantly post-intervention in the experimental group but did not seem to affect the control group. In both groups, fasting blood glucose, 2 hour post-prandial plasma glucose, and insulin resistance index decreased significantly post-intervention (P <0.05). It was also reported that pregnancy outcomes did not differ significantly between the two groups.

The researchers concluded that an appropriate increase in polyunsaturated fatty acid intake did show some benefit in pregnant women with gestational diabetes mellitus as well as the fetus.

Practice Pearls:

  • The ADA guidelines for nutrition recommend that all pregnant women with GDM consult a nutritionist upon diagnosis.
  • The pre-intervention dietary survey showed that local Changzhou women with GDM generally misunderstood what constitutes an appropriate diet; vegetable oil intake was excessive, and energy and macronutrient intake were above requirements.
  • The pregnancy outcomes as well as improvements in blood glucose control, lipid metabolism, and insulin resistance were the same between groups.

Huiyan Wang MD, Hongyi Jiang RD, Liping Yang BSc, et al. “Impacts of dietary fat changes on pregnant women with gestational diabetes mellitus: a randomized controlled study” Asia Pac J Clin Nutr 2015;24(1):58-64.