Mum’s diet mistake linked to child allergies

Pregnant women who eat a low fibre diet may be putting their own lives at risk and their babies are more likely to develop allergies, startling new gut bacteria research shows.

Researchers from the University of Sydney's Charles Perkins Centre and four other Australian universities (the Barwon Infant Study from Deakin University, Monash University, James Cook University and the Australian National University) have found women with low levels of the short chain fatty acid acetate are at high risk of the deadly pregnancy complication pre-eclampsia.

Women with pre-eclampsia develop high blood pressure, have high protein in their urine, suffer swelling and are at risk of liver failure, epileptic seizures and some die.

The research published in the journal Nature Communications has also helped to explain the rising levels of allergies among Australian children. One in 10 Aussie kids now has a food allergy.

 

Changing your diet could reduce the risk of allergies in your baby. Picture: istock
Changing your diet could reduce the risk of allergies in your baby. Picture: istock

The research found babies of mothers with low acetate - produced when the bacteria in our gut breaks down plant fibre - levels develop a much smaller thymus.

The thymus is an important foetal immune organ which produces cells needed to control allergies and auto-immune conditions like diabetes.

The team measured the thymus in the babies of 900 women at their 18-20 week ultrasound.

"At 18-20 weeks the thymus (of babies in women with low acetate levels) was much smaller than in healthy women, at term the thymus was two thirds the size of a healthy baby," Professor Ralph Nanan, of University of Sydney's Charles Perkins Centre, said.

The team then carried out blood tests once the infants were born and found cells for controlling allergies and eczema were also lower at birth and remained low for at least the first four years of life.

Babies from pre-eclampsia pregnancies also had rates of allergies that were two to three times higher than the general population, Professor Nanan said.

"No-one understood the link and here we have the indication that mothers had less acetate, the thymus of their baby was smaller and the baby's T cells were low," he said.

 

Ultrasounds showed foetuses of women with low acetate had smaller thymuses. Picture: Istock
Ultrasounds showed foetuses of women with low acetate had smaller thymuses. Picture: Istock

Experiments in mice showed by increasing the acetate levels it was possible to eliminate the risk to mother and baby.

The simple recommendation to 'eat real food, mostly plants, and not too much' might be the most effective primary prevention strategy for some of the most serious conditions of our time, Professor Nanan said.

"The mother's gut bacteria and diet appear to be crucial to promoting a healthy pregnancy," he said.

"More studies are urgently needed to understand how we can best target this system to reduce the growing burden of immune related diseases in the modern world," said Peter Vuillermin, co-lead of the Barwon Infant Study Health in collaboration with the Murdoch Children's Research Institute (MCRI) and Deakin University.

Professor Nanan is looking for funding to do further research that would compare women who maintained their diet in pregnancy and compared the outcomes to women who ate three times more fibre than normal.

The researchers say simply educating women how to increase the fibre in their diet could turn out to be a very cheap and effective primary health prevention strategy.