Researchers say kids likely to crave unhealthy fare if their mothers ate junk food while pregnant
Aug 15, 2007
Joseph Hall, Health reporter, Toronto Star, Section A
A little ice cream and the occasional pickle is one thing.
But mothers who eat large amounts of junk food during pregnancy and while breastfeeding may pass on lifelong cravings for such unhealthy fare to their children, a new British study out of London's Royal Veterinary College says.
"Women shouldn't justify indulging on junk foods because they're eating for two," says Stéphanie Bayol, a research scientist at the college and the lead study author. "There's more and more evidence this will have consequences for the development and the long-term health of the offspring."
The study, published yesterday in the British Journal of Nutrition, was funded by the Wellcome Trust, the United Kingdom's largest charity.
A Harvard University study released earlier this year showed that women who gain excessive weight while expecting were four times more likely to bear children who were overweight by age three than those who remained slimmer during gestation.
But it's also been suggested that these mothers raise fatter kids because they continue poor eating habits long after giving birth, and pass these on to their children.
The new study, however, suggests that mothers who eat junk food may actually rewire babies' brains, permanently tripping neurological "pleasure centres" that make them likely to choose fatty, sweet or salty foods throughout their lives.
Because their research used rats, Bayol says, it removed human social, cultural and psychological factors that could prompt youngsters to choose burgers, chips and doughnuts.
"What you're left with is a true physiological link between maternal junk food diet ... and the development of appetite and feeding behaviours in the offspring."
In the study, pregnant and lactating rats were fed either typical human junk food –such as doughnuts, muffins and potato chips – or healthy rodent pellets. Researchers found the rats borne of mothers fed a steady diet of junk food were 95 per cent more likely to overeat than the offspring of the healthier eaters.
The junk food offspring also ate an average 22 per cent more calories a day than their counterparts, both of whom were offered a choice of healthy and unhealthy foods.
The study did not actually look at the rodent brains to see what changes may have been occurring in the junk food babies. But Bayol says it's likely the reward centres in the fetal and infant rat brains were turned on by the fats, salts and sugars their mothers were ingesting.
Bayol says previous studies comparing other maternal dietary conditions, such as malnourishment, with fetal development have shown striking similarities between humans and animals. Thus, she believes there is a good chance her rodent findings also apply to people.
Rena Mendelson, a professor of nutrition at Toronto's Ryerson University, says it's been well established that spices and other food compounds find their way into amniotic fluid and breast milk, both of which babies ingest through their mouths. That's how many cultural and familial dietary preferences are set in the womb and during early infancy, Mendelson says.
"And so babies are predisposed to the tastes and the smells that are characteristic of the diets that are consumed by their mother."
It makes "perfect sense" therefore that a preference for fatty, salty and sugary foods could be established in the womb and at a mother's breast.