The researchers from the High Institute of Public Health at Alexandria University and the Egyptian Ministry of Health looked at 675 healthy pregnant women aged 20–45 years.
All had low serum zinc levels and were assigned to one of three groups: the zinc alone group (a daily dose of 30 mg ZnSO4), the combined group (30 mg ZnSO4 plus multivitamins B1, B6, D3, C and E) and the control group (a placebo of 270 mg lactose).
They were monitored from time of recruitment to one week after delivery.
Published in the British Journal of Nutrition, the results showed stillbirth and preterm delivery as well as early neonatal morbidity – mainly respiratory tract infections – were significantly lower for the two supplemented groups compared to the placebo group.
They also found both single and combined zinc supplements were almost equally effective in reducing second- and third-stage pregnancy complications.
There was no significant difference in birth weight across the three groups.
Zinc is necessary for ‘normal’ pregnancy outcomes as well as the child’s growth, immune function and neuro behavioural development.
The neglected nutrient
Currently, through Egypt’s antenatal care (ANC) programme, pregnant women are routinely given iron and folic acid supplements but not zinc.
The researchers recommended zinc be included in the programme for women at risk of deficiency and urged the results of this latest study be taken into account when calculating cost effectiveness.
According to the International Zinc Nutrition Consultative Group Steering Committee, about 9% of the population in Egypt was at risk of inadequate zinc intake. While a 2008 national survey showed 29% of children under five were stunted.
Dietary advice on zinc was also called for, they added.
“Nutritional health education should be used as a preventive approach to allow the large sector of the low-income population in our society to maximise the use of the limited resources in the best means.”
Too much of a good thing?
Meanwhile the UK's National Health Service (NHS) recommends no more than 25 mg of zinc supplements a day, unless advised to by a doctor. This is 5 mg more than that given in the supplement groups of this study.
According to the NHS choices website: "Taking high doses of zinc reduces the amount of copper the body can absorb. This can lead to anaemia and weakening of the bones."
Source: British Journal of Nutrition
Published online ahead of print, doi:10.1017/S000711451500166X
“The effect of zinc supplementation on pregnancy outcomes: a double-blind, randomised controlled trial, Egypt”
Authors: S. A. Nossiera1, N. E. Naeima, N. A. El-Sayeda and A. A. Abu Zeid