Alignment of the Planetary Health Diet with Pregnancy Dietary Guidelines: Insights from Two Cohorts

The Planetary Health Diet (PHD) is a mostly plant-based diet that aims to optimise human health whilst minimising the environmental impact of food production. Limited data exists on whether the PHD fulfils key nutritional requirements during pregnancy. This research aimed to examine the PHD in early pregnancy and how it aligns with daily nutrient intake and European Food Safety Authority (EFSA) dietary guidelines. Pregnant women (n=678) from two Irish cohorts (ROLO and MicrobeMom) were analysed. Dietary intakes in early pregnancy were determined using a 3-day food diary and used to calculate PHD Index (PHDI) scores. Women were dichotomised by the median score, to create a 'High PHDI' (>88.99) and a 'Low PHDI' group (≤88.99). Differences in nutrient intakes and adherence to dietary guidelines between 'High' and 'Low' PHDI groups were explored using Mann-Whitney U tests for non-normally distributed variables and chi-square tests for categorical variables. Compared to those with a 'Low' score, those with a 'High' PHDI score reported higher intakes of dietary fibre (g/day) (17.32(13.39,21.08) vs 21.74 (18.28,25.88),<i>p</i><0.001), iron (mg/day) (10.48(8.48,12.82) vs 12.06(9.48,14.60),<i>p</i><0.001), folate (µg DFE/day) (250.73 (193.88,312.45) vs 279.57(219.43,356.81),<i>p</i><0.001), and calcium (mg/day) (837.75(695.36,1056.72) vs 956.57(751.84,1155.03),<i>p</i><0.001). Compared to those with a 'Low PHDI' score, a greater proportion of women in the 'High PHDI' group met EFSA recommendations for dietary fibre intake (10.3% vs 28.9%,<i>p</i><0.001). The PHD may support maternal nutritional adequacy in pregnancy, while promoting environmental sustainability. Our findings provide valuable insights that can inform future dietary recommendations for pregnancy, contributing to both maternal health and planetary well-being.