Role of Macronutrient Diet Composition and Infant Metabolic Outcomes in Gestational Diabetes
Condition: Gestational Diabetes Mellitus
MeSH terms: Diabetes, Gestational; Diabetes Mellitus
Study type: Interventional

Summary: 
      A better understanding of the optimal diet for women with gestational diabetes is fundamental
      to the management of this rapidly growing problem in pregnancy. Careful comparison studies of
      the current low- carbohydrate, higher-fat diet versus a diet higher in complex carbohydrate
      but lower in fat is critical in order to determine which diet results in a more favorable
      maternal 24-hour glucose, lipid, and inflammatory profile, all of which directly effect
      optimal fetal growth and may influence the future health of the offspring.
    

Detailed description: 
      Despite the doubling in the prevalence of gestational diabetes mellitus (GDM) over the last
      10 years, dietary management guidelines remain ambiguous due to the paucity of randomized
      controlled trials. New diagnostic criteria recently developed for the diagnosis of GDM are
      expected to increase the prevalence to 10-15% of all pregnant women. There is growing
      recognition that GDM has long-term implications on maternal risk for diabetes and that the
      intrauterine GDM environment is an independent risk factor for childhood obesity and impaired
      glucose tolerance. Yet, how diet can be used to modify fetal fuel and attenuate this risk
      remains unknown in humans. Fundamental to the management of GDM is dietary intervention, yet
      the historic practice of advising a low-carbohydrate (CHO), higher-fat diet has not been
      sufficiently tested. Both animal and non-human primate data support a fetal programming
      influence that maternal high-fat diets may promote insulin resistance, glucose intolerance,
      and hepatic steatosis in the offspring. Recent human data suggest that high maternal
      triglycerides (TG) and free fatty acids (FFA), variables sensitive to dietary manipulation,
      are independent risk factors for fetal macrosomia and adiposity. As a result, consensus
      groups have abandoned any specific diet recommendations for women with GDM. Despite the
      pivotal role of diet therapy in the treatment of GDM, no randomized trials have directly
      compared glycemic and lipoprotein profiles of the conventional higher-fat diet with any other
      diet. To address this critical need, the aims of this randomized cross-over trial are to
      study the effects of a high complex carbohydrate/low-fat diet (HC/LF; 60% CHO, 25% fat, 15%
      protein) compared to the usual care, low-CHO/higher fat diet (LC/HF; 40% CHO, 45% fat, and
      15% protein) in GDM women on: 1) 72-hour glycemic profiles using a continuous glucose
      monitoring system within subjects; 2) postprandial lipemia by measuring serial plasma TG and
      FFA over a 5-hour, post-breakfast meal period within subjects; and 3) maternal lipoproteins,
      inflammatory profiles, and in-vitro adipose tissue lipolysis after 6-8 weeks of diet therapy
      between subjects. We will also measure neonatal adiposity by air displacement plethysmography
      and newborn markers of lipid peroxidation, inflammation, and dietary fat intake in the babies
      born to mothers with GDM. This pilot study will directly test which GDM diet is most
      effective in limiting maternal hyperglycemia and hyperlipidemia in a randomized controlled
      fashion, potentially optimizing fetal substrate availability and fetal growth. Our goal is to
      determine which diet intervention might favorably impact a cycle that could otherwise
      perpetuate future diabetes, obesity, and CVD in both mother and offspring.
    

Intervention name(s): Low-Carbohydrate/Higher Fat Diet; High Carbohydrate/Low fat diet
Intervention type(s): Other; Other
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: continuous glucose monitoring; gestational diabetes; diet therapy