What a mother eats while she is pregnant may have permanent consequences on the food preferences of her child and not always in a good way. Several studies coming out of the University of Washington, Princeton University, the Yale University School of Medicine and the National Institute on Drug Abuse have shown that the excess intake of sugar can produce what is called endogenous opioid dependency. Opioids are chemicals that can produce a feeling of euphoria, and excess intake can act like a drug creating its own opium-like food addiction. Up until now studies have only been done on rats where they were fed either normal rodent food or high fat/high sugar human food (we used to call this 'junk food'). The offspring of females fed the human food while they were pregnant or lactating showed a marked preference for foods rich in sugar and fat. They also ate more. This behavior was predicted in humans, but never tested.

Now there is some data to suggest that children exposed to maternal junk food in the womb or early in life may find it harder to resist an unhealthy diet later in life just as the rats did. A recent study published in the Federation of American Societies for Experimental Biology journal, found that babies of mothers having a diet largely made up of processed foods high in fat in sugar have less sensitivity to opioids and are more likely to overeat these foods in both childhood and adulthood. Dr. Bev Mhlhusler, from Adelaide University found that the opioid signaling pathway the reward pathway in offspring of mothers with high fat and sugar diets were less sensitive than those whose mothers were eating a standard diet. Children born to these mothers needed to eat more fat and sugar to get the same good feeling, increasing their preference for high fat and high sugar food. Mothers who eat these foods while pregnant may be setting up their children to crave larger quantities of those foods. This is the first time that high fat and high sugar food consumption during pregnancy and breastfeeding has actually demonstrated an influence on food consumption later in life.

This is important information in light of the rapidly rising rate of childhood obesity. Until we have a better understanding of this phenomenon, pregnant women should be mindful that a baby's reward pathways may be strongly influenced by their own diet behaviors. This adds strength to the recommendation to eat a healthy, well balanced diet during pregnancy.

Dr. SeAnne Safaii, Ph.D., RD, LD, is an assistant professor at the University of Idaho.