Does the impact of a plant-based diet during pregnancy on birth weight differ by ethnicity? A dietary pattern analysis from a prospective Canadian birth cohort alliance

BMJ Open. 2017 Nov 14;7(11):e017753. doi: 10.1136/bmjopen-2017-017753.

Abstract

Objective: Birth weight is an indicator of newborn health and a strong predictor of health outcomes in later life. Significant variation in diet during pregnancy between ethnic groups in high-income countries provides an ideal opportunity to investigate the influence of maternal diet on birth weight.

Setting: Four multiethnic birth cohorts based in Canada (the NutriGen Alliance).

Participants: 3997 full-term mother-infant pairs of diverse ethnic groups who had principal component analysis-derived diet pattern scores-plant-based, Western and health-conscious-and birth weight data.

Results: No associations were identified between the Western and health-conscious diet patterns and birth weight; however, the plant-based dietary pattern was inversely associated with birth weight (β=-67.6 g per 1-unit increase; P<0.001), and an interaction with non-white ethnicity and birth weight was observed. Ethnically stratified analyses demonstrated that among white Europeans, maternal consumption of a plant-based diet associated with lower birth weight (β=-65.9 g per 1-unit increase; P<0.001), increased risk of small-for-gestational age (SGA; OR=1.46; 95% CI 1.08 to 1.54;P=0.005) and reduced risk of large-for-gestational age (LGA; OR=0.71; 95% CI 0.53 to 0.95;P=0.02). Among South Asians, maternal consumption of a plant-based diet associated with a higher birth weight (β=+40.5 g per 1-unit increase; P=0.01), partially explained by cooked vegetable consumption.

Conclusions: Maternal consumption of a plant-based diet during pregnancy is associated with birth weight. Among white Europeans, a plant-based diet is associated with lower birth weight, reduced odds of an infant born LGA and increased odds of SGA, whereas among South Asians living in Canada, a plant-based diet is associated with increased birth weight.

Keywords: PCA; birth weight; diet pattern; nutrition.

MeSH terms

  • Adult
  • Asian People
  • Birth Weight*
  • Canada / epidemiology
  • Cooking
  • Diet, Healthy / ethnology*
  • Diet, Vegetarian / ethnology*
  • Diet, Western / ethnology*
  • Energy Intake
  • Female
  • Fetal Macrosomia / ethnology
  • Food
  • Humans
  • Infant, Small for Gestational Age
  • Pregnancy
  • Term Birth
  • White People
  • Young Adult