Midwifery and plant-based diets

In a study of over 250 women (both pregnant and non-pregnant) based in Ireland, De Benedictus et al (2022) evaluated dietary intake and the bioavailability of zinc, finding that ‘58.14% of women and 38.39% of pregnant women participating in the study are at risk of inadequate zinc intake, and 29.07% of women and 9.28% of pregnant women may be considered zinc-deficient due to dietary inadequacy, based on their intake of bioavailable zinc’. The authors cited evidence that zinc absorption in vegetarian diets is between 15% and 26% instead of the 33% and 35% seen in omnivorous diets, because phytate-rich diets can inhibit zinc absorption in the small intestine. The authors then observed that ‘all participants whose food frequency questionnaires indicated a vegetarian diet were in the “at-risk” and “zinc-deficient” categories’ (De Benedictus et al, 2022).

A prospective observational Israeli study of 273 women (112 omnivores, 37 fish-eaters, 64 lacto—ovo—vegetarians, and 60 vegans) with a singleton pregnancy, who maintained the same diet before and throughout gestation, reported that ‘[t]he vegan diet was significantly associated with an increased risk of small-for-gestational-age newborns compared only to an omnivore diet’ (Avnon et al, 2021).