7 May 2018

Junk food may double risk of infertility

Clinical Women

Who would have thought? A dietician might be a useful resource for couples trying to become pregnant.

New Australian-led research found that women who ate junk food four times a week or more were twice as likely to be infertile compared with those who rarely ate it. And junk-food eaters, on average, took longer to become pregnant than their healthier-eating colleagues. 

Similarly, women who ate the most fruit, reporting three or more serves a day, were 50% less likely to be infertile compared with those who said they only ate fruit three or fewer times per month. 

“I’d like to see all GPs and fertility specialists referring to a fertility dietitian prior to conception,”  accredited fertility dietitian Melanie McGrice said. 

The study highlighted a problem Ms McGrice increasingly sees among women who mistakenly believe that fruit is in the same basket as soft drinks and other sugary foods, and ought to be avoided. 

While obesity and smoking are now established impediments to pregnancy, questions still surround the role of diet, especially in groups of women who are not undergoing fertility treatment. 

This study took 5600 nulliparous women at their first antenatal visit and asked them about their pre-conception diets and time to pregnancy. 

“Most of the women did not have a history of infertility,” lead author and University of Adelaide researcher Dr Jessica Grieger said. This set the study apart from much other research in the field which has focused on women undergoing fertility treatment. 

One in 12 were classed as “infertile” because it took them longer than a year to conceive, whereas two in five became pregnant within a month. 

The highest fruit eaters had an 8% chance of being infertile, whereas those who ate the least amount of fruit had a 12% chance. Similarly, rarely eating junk food was associated with an 8% chance of infertility, compared with 16% for the group who ate the most. 

Interestingly, fertility rates did not appear to be affected by how much fish or green leafy vegetables the women ate. 

The authors controlled for common causes of infertility, such as BMI, maternal age, smoking and drinking. 

“As diet is a modifiable factor, our findings underscore the importance of considering pre-conception diet to support timely conception for women planning pregnancy,” Dr Grieger said.  

The AMA’s spokesperson for obstetrics and gynaecology said the study yet again supported the importance of a healthy diet for couples trying for a baby. 

“Another week, another good reason for women hoping to start a family to make sure they ditch the fast food and switch over to a healthy diet,” Dr Gino Pecoraro, a senior lecturer in obstetrics and gynaecology at the University of Queensland, said. 

While the study backed up previous research, Dr Pecoraro noted that studies relying on retrospective self-report “can notoriously be inaccurate”. 

It also failed to take into account the father’s diet, he said. 

Human Reproduction 2018; online 4 May