The influence of maternal vegetarian diet on essential fatty acid status of the newborn.

OBJECTIVES

To evaluate whether a maternal vegetarian diet influences the essential fatty acid status of the newborn and whether this is related to outcome of pregnancy.

DESIGN

Dietary intake and the fatty acid composition of plasma phospholipids were determined in 24 South Asian vegetarian and 24 white omnivore non-pregnant premenopausal women randomly selected from the general population of North London. Umbilical cords and cord blood were collected at delivery from 48 South Asian vegetarian women and 98 white omnivores from the same catchment area along with details of antenatal history and the outcome of pregnancy. The fatty acid composition of the cord arteries and that of cord plasma phospholipids were analysed in a subset of 32 pairs of subjects, who were matched for maternal age, gestational age, parity and sex of infant.

RESULTS

Intakes of linoleic acid (18:2n-6) expressed as proportion of the dietary energy and the ratio of linoleic to alpha-linolenic acid (18:3n-3) were higher in the vegetarian women, and eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) were absent from their diets. The proportion of linoleic acid, as well as the absolute concentration, was greater and those of EPA and DHA were lower in plasma phospholipids, plasma free fatty acid and total plasma lipids of the vegetarians compared with the white subjects. The proportion of DHA was lower (P > 0.001) but that of docosapentaenoic acid (22:5n-6) was greater (P < 0.001) in cord those from the omnivores. The ratio of 20:3n-9/20:4n-6 was elevated in cord artery but not in cord plasma phospholipids in both groups. Early onset of labour and the duration of gestation was 5.6 days shorter. Birth weight, head circumference and length were lower in the infants born to South Asian vegetarians even after adjusting for maternal height, duration of gestation, parity, gender of infants and smoking habits. Multivariate analysis did not reveal any relationship between the proportions of DHA in plasma or cord artery phospholipids and the birthweight or head circumference of the infants.

CONCLUSION

This study demonstrates that vegetarians give birth to infants with less DHA in their plasma and cord artery phospholipids but this did not appear to be independently related to the outcome of pregnancy.