December 2, 2011

expert reaction to study of micronutrient supplementation and women’s fertility outcomes

This study examined the link between dietary micronutrient supplementation and women’s chances of conceiving during fertility treatment.

Catherine Collins, Principal Dietician, St Georges Hospital NHS Trust, said:

“This study showed the benefit of a multivitamin and mineral supplement on conception in women undergoing fertility treatment, two thirds of whom had PCOS as their cause of their infertility. Although the researchers claimed their diets were nutritionally adequate no robust data provided to confirm this – a major concern for any trial making nutritional claims. We know that broad-spectrum supplements can correct dietary deficiencies and boost blood levels of iron, B12, folic acid and vitamin D – as was shown in this study which suggests these women had low intakes pre-conception.

“As this study was of women with conception problems there’s no evidence to suggest every woman considering pregnancy should take them. Similarly, n-acetyl cysteine and arginine have been shown to improve the efficacy of IVF treatments in a small number of studies, but there’s no evidence to support their use in natural conception. However, the nutritional advice for women contemplating pregnancy remains unchanged – take folic acid supplements until 12 weeks of pregnancy and if you decide on a multi-nutrient supplement for nutritional insurance make sure it’s one suitable for pregnancy, as the vitamin A content is lowered to ensure safety of the developing baby. But it’s important to remember a supplement can’t substitute for a varied healthy diet providing sufficient protein and calories to sustain a healthy pregnancy.”

Prof Alison Murdoch, Professor of Reproductive Medicine at Newcastle University, said:

“This is not a well designed study; the numbers are small and the authors have not provided any evidence of causation. The results are unusual and difficult to explain. They describe it only as a pilot study – which it clearly is. I know how it will be picked up by the press and it will cause unnecessary anxiety for infertile patients. A good diet is important if you are trying to conceive but most of us get sufficient nutrition in a normal diet and unless there is no evidence of dietary deficiency, this does not provide evidence of the need for supplements.”

Dr. Allan Pacey, Senior Lecturer in Andrology at the University of Sheffield, said:

“The influence of nutrition on our fertility is of general interest to the public and professionals, but there are relatively few studies which have examined this systematically and few which have shown direct benefits of taking supplements to enhance things.

“Therefore, on the face of it, this study is interesting but we should acknowledge that this is a relatively small number of patients and the study would need to be repeated in a larger trial before we could be certain of the results.

“I can’t help but thinking that for most people, just general dietary advice would achieve the same effect and a good basket of fresh fruit and vegetables from the greengrocer each week would have much the same effect if their diet was poor.”

Glenys Jones, Nutritionist, MRC Human Nutrition Research, said:

“This is an interesting study and supports the body of evidence that diet plays an important role in supporting women’s health and their fertility. However this study alone cannot result in the general recommendation that all women undergoing fertility treatment should take a pre-conception multi-vitamin as it is a very small single study and further large-scale research is required to investigate if this is reproducible in a larger more diverse group of women.”

‘Prospective randomized trial of multiple micronutrients in subfertile women undergoing ovulation induction: a pilot study’ by Rina Agrawal et al., published in Reproductive BioMedicine Online on Friday 2nd December 2011.