Zn is an essential element for human growth. The nutritional adequacy of dietary Zn depends not only on the total Zn intake, but also on the type of food source (i.e. of plant or animal origin). We investigated the association between maternal dietary Zn intake from animal and plant food sources and fetal growth. A total of 918 pregnant women at 12–28 weeks of gestation were selected from the Mothers and Children's Environmental Health study in Korea. Dietary intakes in mid-pregnancy were estimated by a 24 h recall method, and subsequent birth weight and height were obtained from medical records. Multiple regression analysis showed that maternal Zn intake from animal food sources and their proportions relative to total Zn intake were positively associated with birth weight (P = 0·034 and 0·045, respectively) and height (P = 0·020 and 0·032, respectively). Conversely, the percentage of Zn intake from plant food sources relative to total Zn intake was negatively associated with birth height (P = 0·026) after adjustment for covariates that may affect fetal growth. The molar ratio of phytate:Zn was negatively associated with birth weight (P = 0·037). In conclusion, we found that the absolute amounts of Zn from different food sources (e.g. animal or plant) and their proportions relative to total Zn intake were significantly associated with birth weight and height. A sufficient amount of Zn intake from animal food sources of a relatively higher Zn bioavailability is thus encouraged for women during pregnancy.

We examined the relationship between dietary folate intake and periconceptional use of folic acid (FA) supplements, and small-for-gestational age for weight (SGA-W) and height (SGA-H). The study is based on 786 Spanish women aged 16 years or above, who attended the first-term prenatal population-based screening programme (10–13 weeks) at the reference hospital ‘La Fe’, Valencia, with singleton pregnancy. Periconceptional use of FA supplements was categorised as non-users, moderate users ( ≤ 1 mg/d) and high users (>1 mg/d). Babies born to mothers who used high doses of FA supplements had a significant reduction in mean birth height compared with babies of non-users (β = − 0·53, 95 % CI − 0·96, − 0·09). As regards weight, mothers using moderate and high doses of FA supplements had lower-birth-weight babies for gestational age than non-users (β = − 22·96, 95 % CI − 101·14, 55·23; β = − 89·72, 95 % CI − 188·64, 9·21, respectively), although these decreases were not significant. Results from the multivariate logistic regression models showed that high FA supplement users had a higher significant risk for SGA-H (OR 5·33, 95 % CI 2·08, 13·7), and that users of moderate doses were not associated with a higher risk of either a SGA-W or a SGA-H baby. In contrast, increased quintiles of the dietary intake of folate were associated with a decreased risk of SGA-W (P for trend = 0·002), although no association was observed for SGA-H. Our findings suggest that periconceptional use of FA supplements greater than 1 mg/d is associated with decreased birth height and may entail a risk of decreased birth weight.