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OLIDIAG Study: Extra Virgin Olive Oil Supplementation in the Diet of Women with Gestational Diabetes Mellitus-A Randomized Clinical Trial.

  • 2026-03-31
  • Nutrients 18(7)
    • Alicia Jawerbaum
    • Silvia Gorban de Lapertosa
    • Magdalena Rey
    • Inés Argerich
    • Mariano Reynoso
    • María Celeste Muntaner
    • Celina Bertona
    • Verónica Kojdamanian Favetto
    • Esteban Díaz
    • Stella Sucani
    • Dalmiro Gomez Ribot

Study Design

Type
Randomized Controlled Trial (RCT)
Sample size
n = 190
Population
190 patients with GDM
Methods
multicenter, parallel, randomized controlled trial; Intervention group received indication to consume three tablespoons of extra virgin olive oil daily
  • Large Human Trial
  • Rigorous Journal

Background/objectives

Gestational diabetes mellitus (GDM) is a prevalent metabolic disease associated with maternal and neonatal complications. Diets enriched with extra virgin olive oil may benefit metabolism and provide antioxidant effects. We aimed to evaluate the effects of dietary supplementation with extra virgin olive oil on metabolic parameters and insulinization rate in women with GDM.

Methods

This is a multicenter, parallel, randomized controlled trial in which 190 patients with GDM were enrolled before week 29 of gestation and randomized into the Control group and the Intervention group. Patients in the Intervention group received the indication to consume three tablespoons of extra virgin olive oil (EVOO) daily. At term, metabolic parameters, insulin requirement and maternal and neonatal outcomes were evaluated.

Results

Control and Intervention groups showed no differences in maternal age (31.7 ± 6.0 and 32.4 ± 5.2 years, respectively) or gestational age (26.5 ± 3.6 and 26.7 ± 3.3 weeks, respectively) at enrollment. Primary outcomes showed that EVOO consumption was associated with a reduction in insulin requirement (RR 0.595, 95% CI 0.361-0.967, p < 0.05). There was a significant reduction in triglyceridemia in the EVOO-supplemented group compared to controls (MD -43.3 mg/dL, 95% CI -66.8--19.8, p < 0.01). There were no effects of the intervention on gestational weight gain. As secondary outcomes, maternal BMI and gestational age at delivery showed no changes between the groups. Although maternal and neonatal composite outcomes were not significantly reduced, the rate of neonates with more than one complication (RR 0.340, 95% CI 0.133-0.870, p < 0.05) and NICU requirement (RR 0.367, 95% CI 0.140-0.939, p < 0.05) were significantly reduced in the Intervention group.

Conclusions

In GDM, maternal dietary supplementation with extra virgin olive oil resulted in reduction in maternal triglyceridemia, need of insulinization and neonatal complications.

Research Insights

  • Olive Oil→Reduced Body Mass Index

    maternal BMI and gestational age at delivery showed no changes between the groups

    Effect
    Neutral
    Effect size
    Small
    Dose
    three tablespoons daily
  • Olive Oil→Reduced Gestational Age at Delivery

    gestational age at delivery showed no changes between the groups

    Effect
    Neutral
    Effect size
    Small
    Dose
    three tablespoons daily
  • Olive Oil→Reduced Gestational Weight Gain

    There were no effects of the intervention on gestational weight gain

    Effect
    Neutral
    Effect size
    Small
    Dose
    three tablespoons daily
  • Olive Oil→Reduced Insulin Requirement

    EVOO consumption was associated with a reduction in insulin requirement (RR 0.595, 95% CI 0.361-0.967, p < 0.05)

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    three tablespoons daily
  • Olive Oil→Reduced Maternal and Neonatal Composite Outcome

    maternal and neonatal composite outcomes were not significantly reduced

    Effect
    Neutral
    Effect size
    Small
    Dose
    three tablespoons daily
  • Olive Oil→Reduced NICU Requirement

    NICU requirement (RR 0.367, 95% CI 0.140-0.939, p < 0.05) were significantly reduced in the Intervention group

    Effect
    Beneficial
    Effect size
    Large
    Dose
    three tablespoons daily
  • Olive Oil→Reduced Neonatal Complication

    the rate of neonates with more than one complication (RR 0.340, 95% CI 0.133-0.870, p < 0.05) ... were significantly reduced in the Intervention group

    Effect
    Beneficial
    Effect size
    Large
    Dose
    three tablespoons daily
  • Olive Oil→Reduced Triglyceride Levels

    There was a significant reduction in triglyceridemia in the EVOO-supplemented group compared to controls (MD -43.3 mg/dL, 95% CI -66.8--19.8, p < 0.01)

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    three tablespoons daily
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