Women know they shouldn't smoke, drink alcohol, or do drugs while they're pregnant. But a new study on rats suggests that even females who eat junk food during pregnancy may be setting up their children for a lifetime of addiction.
A team of Australian scientists found a chemical basis behind this junk food addiction, pinpointing psychoactive chemicals that are produced as a reward response and trigger a natural high in the brain.
"When we eat foods high in fat and sugar, this increases the release of opioids and the feel-good peptide dopamine in the reward centre of the brain and creates a pleasurable sensation that keeps us going back for more," Dr. Beverly Mühlhäusler, a postdoctoral fellow at the University of Adelaide who led the study, told The Huffington Post in an email.
For the study, the team fed some of the rats a diet high in fat and sugar -- foods like sugary cereal, meat patties, potato chips and peanut butter. Then they looked at these rats' offspring after they were weaned, and found that the offspring of junk food-fed mothers preferred more high-fat foods compared to a control group fed a diet low in fat and sugar. They also found that the gene expression in the reward pathway of these rats' brains was altered -- they had an increased predisposition to junk food addiction later in life.
"In the same way that someone addicted to opioid drugs has to consume more of the drug over time to achieve the same 'high', continually producing excess opioids by eating too much junk food results in the need to consume more foods full of fat and sugar to get the same pleasurable sensation," said Dr. Mühlhäusler.
But does this junk food phenomenon extend to humans, too? The researchers suspect so.
"The take-home message for women is that eating large amounts of junk food during pregnancy and while breastfeeding will have long-term consequences for their child's preference for these foods, which will ultimately have negative effects on their health," Dr. Mühlhäusler said in the statement.
The research, published recently in The Journal of the Federation of American Societies for Experimental Biology, also suggests that overcoming this predisposition for junk food addiction later in life may be difficult. Now, the team is examining whether it's even possible.
"The results so far indicate that the effects of prenatal exposure to junk food on the reward system are long lasting," Dr. Mühlhäusler said.