Table 1.
Main findings of the studies concerning the impact of a plant-based diet on gestational diabetes mellitus.
| Reference | Type of Study | Main Outcome | Number of Participants | Event | Definition of Plant-Based Diet |
|---|---|---|---|---|---|
| Arora et al., India [41] | Observational, cross-sectional | An increased risk of developing GDM was associated with a non-vegetarian diet | 5100 women | The prevalence of GDM was 35% using WHO 2013 criteria | Vegetarian diet |
| Barrett et al., Australia [44] | RCT | A vegetarian diet in early pregnancy increased the presence of short-chain fatty acid bacteria producers without any influence on GDM risk | 9 following a vegetarian diet and 18 an omnivorous one | Microbiome alpha diversity was similar, while beta diversity was reduced, in vegetarians | Vegetarian diet |
| De Filippis et al., Italy [42] | Observational | An increased consumption of plant foodstuffs based on a MedDiet was associated with beneficial microbiota improvements | 51 vegetarians, 51 vegans, and 51 omnivores | Positive correlation between consumption of vegetables and short-chain fatty acids, Prevotella, and Firmicutes in the gut microbiome | MedDiet |
| García de la Torre et al., Spain [35] | Observational, prospective | Following a MedDiet with EVOO and pistachio supplementation before 12 gestational weeks showed a lower GDM incidence and better maternal–fetal outcomes | 932 women | The incidence of GDM was lower in the intervention group than in the controls (RR 0.81) | MedDiet |
| Izadi et al., Iran [39] | Observational, case-control | Adherence to the DASH and MedDiet was associated with a reduced risk for GDM | 200 women with GDM and 260 without GDM | A higher adherence to DASH was related to 71% reduced risk for GDM | DASH and MedDiet |
| Jali et al., India [40] | Observational, cross-sectional | Non-vegetarian pregnant women showed an increased risk for glucose intolerance | 325 women: 202 vegetarian and 123 non-vegetarian | 52 women (16%) presented GDM. An increased prevalence of GDM in patients following a non-vegetarian diet compared to a vegetarian diet (65.5% vs. 38.5%) | Vegetarian diet |
| Kahleova et al., Czech Republic [33] | RCT | A low calorie vegetarian diet improved insulin sensitivity | 37 following a vegetarian diet and 37 following a conventional diabetic diet | A vegetarian diet improved adipokine levels and oxidative stress markers compared to a conventional diabetic diet over 24 weeks | Vegetarian diet |
| Karamanos et al., Mediterranean countries [36] | Observational, prospective | Adhering to a MedDiet pattern decreased the incidence of GDM | 1076 women | The incidence of GDM was lower in subjects with better adherence to the MedDiet (8.0% vs. 12.3%) | MedDiet |
| Kesary et al., Israel [19] | Observational, retrospective | A vegan diet is a protective factor from maternal weight gain but increased the risk for a lower birth weight | 234 vegans, 133 vegetarian, and 1052 omnivores | A vegan diet in pregnancy was associated with a lower birth weight centile compared to omnivores (42.6 ± 25.9 vs. 52.5 ± 27.0; p < 0.001) | Vegan and vegetarian diet |
| Mak et al., China [38] | Observational, prospective | Following an early pregnancy dietary pattern did not significantly increase the risk of GDM in patients. However, a high protein–low starch diet was associated with a decrease in risk for GDM among obese women | 1337 women | 199 women (14.9%) developed GDM | Plant-based and a high protein–low starch pattern diet |
| Olmedo-Requena et al., Spain [37] | Observational, case-control | A high adherence to a MedDiet before pregnancy was strongly associated with a decreased risk in GDM | 291 with GDM and 1175 without GDM | A high MedDiet adherence was associated with lower GDM risk (aOR 0.61; p = 0.028), while a very high MedDiet adherence was more strongly associated (aOR 0.33; p = 0.005) | MedDiet |
| Zhang et al., USA [45] | Observational, prospective | A low fiber and high sugar intake diet increased the risk for GDM | 13,100 women | 758 with GDM. Each 10-g/day increment in total fiber intake was associated with a 26% reduction in GDM risk | Diet rich in fiber |
| Zulyniak et al., Canada [34] | Observational, prospective | A plant-based diet was associated with lowering the birth weight for women of Caucasian ethnicity and increasing it in Asiatic women living in Canada | 3997 women | The plant-based diet was inversely associated with birth weight (β = −67.6 g per 1-unit increase; p < 0.001) | Plant-based diet |