a1 Department of Obstetrics and Gynaecology, Bosch Medicentrum (Groot Ziekengasthuis), 's-Hertogenbosch, The Netherlands
a2 Department of Human Nutrition, Wageningen Agricultural University, Wageningen, The Netherlands
a3 Department of Obstetrics and Gynaecology, Catholic University of Nijmegen, St. Radboud Hospital, Nijmegen, The Netherlands
In ninety-four Dutch nulliparous women the effects of a low-Na diet in pregnancy on blood pressure, energy and nutrient intake, Ca metabolism, Zn and Mg status and body composition were studied longitudinally. The women were randomly divided into an intervention group (n 41), which used a low-Na diet (mean urinary Na excretion 61 mmol/24 h) from week 14 of pregnancy until delivery and a control group (n 53; mean urinary Na excretion 142 mmol/24 h). No effect of the diet on blood pressure was observed. The use of a low-Na diet resulted in significantly reduced intakes of energy, protein, carbohydrates, fat, Ca, Zn, Mg, Fe and cholesterol. However, the women on the low-Na diet appeared to be able to adapt quite well to the reduced intake since Ca, Zn and Mg homeostasis was maintained. In the case of Ca and Mg this was probably due to the observed reduced urinary excretions of these nutrients. Non-significant reductions in weight gain (1·5 kg) and fat-mass gain (0·9 kg) over pregnancy were found in the women on the low-Na diet. No significant effects of the diet on birth weight or placental weight were observed.
(Received March 13 1995)
(Revised July 22 1996)
(Accepted July 26 1996)