Mothers who eat high fat, high sugar diet during pregnancy have already programmed their babies to be addicted to junk food by the time they are weaned, according to a study from the University of Adelaide.
In their study with laboratory rats, Dr Beverly Muhlhausler, Postdoctoral Fellow in the University's FOODplus Research Centre, and her colleagues, found that a junk food diet during pregnancy and lactation desensitized the mesolimbic reward pathway (the reward system in the brain) fuelled by these highly palatable foods.
Advertisement'We found that the opioid signalling pathway (the reward pathway) in these offspring was less sensitive than those whose mothers were eating a standard diet,' Dr Muhlhausler says.
The opioid system plays a role in energy-driven feeding as well as food hedonics resulting in a higher intake of junk food and these are produced by the body as a reward response. Opioids target the brain's reward system by flooding the circuit with dopamine, a 'feel good' neurotransmitter that regulates feelings of pleasure.
So, being addicted to junk food is very similar to that of being addicted to drugs.
'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,' says Muhlhausler.
This study showed that babies born to a mother who mostly ate junk food would need to eat more fat and sugar to get the same good feeling, because the opioid receptors in the babies change making the reward system less sensitive thus increasing their preference for junk food. These babies tend to grow up into high-fat, high-sugar food junkies leading to health problems.
What this means is, mothers eating a lot of junk food while pregnant are setting up their children to be addicted. Unfortunately, the alterations to the opioid receptors are permanent found the researchers.
'It is important to try and understand the effects of the maternal diet at a very early stage in the offspring to see what systems could be targeted, if any, to reverse the problem,' Muhlhausler opined.
'Although our research shows that many of the long-term health problems associated with maternal junk food diets can be avoided if offspring carefully follow a healthy diet after weaning, they are always going to have a predisposition for over-consumption of junk food and obesity. It's going to make it much more difficult for them to maintain a healthy body weight', she continued. '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'.