Researchers identify brain changes linked to stronger food cravings during pregnancy.
Pregnancy can bring strong cravings for certain foods, leaving many women wondering why particular snacks and meals suddenly become so appealing. Researchers at Louisiana State University’s Pennington Biomedical Research Center have identified changes in brain activity that may help explain why food cravings become stronger during pregnancy. The findings come from a study in mice and provide new information about how pregnancy may affect the brain systems that control food-seeking behavior.
The research team examined serotonin-producing nerve cells in a brain region called the dorsal raphe nucleus. Serotonin is a chemical messenger that helps nerve cells communicate and plays a role in several brain functions. The researchers found that these nerve cells became less active during pregnancy in the animals studied. This change was linked to increased behavior resembling food cravings.
The study, published in Nature Neuroscience, was led by Dr. Yanlin He of Pennington Biomedical Research Center, along with Dr. Pingwen Xu of the University of Illinois Chicago and Dr. Chunmei Wang of Baylor College of Medicine. Researchers discovered that a potassium channel called SK3 played a role in the changes seen during pregnancy. Potassium channels help control the electrical activity of nerve cells, affecting how often they send signals. During pregnancy, SK3 activity increased in the serotonin-producing cells of the dorsal raphe nucleus. This reduced their firing activity and appeared to change the way the brain controlled food-seeking behavior.
To test whether SK3 was responsible, researchers removed the channel from the serotonin-producing nerve cells in the animals. This prevented the usual drop in nerve cell activity during pregnancy and greatly reduced the food-craving-like behavior. The team also tested what happened when SK3 activity was increased in female mice that were not pregnant. In these animals, the changes in brain activity and food-seeking behavior resembled those observed during pregnancy. These results supported the idea that SK3 activity was involved in the process.
The researchers also examined a connection between the dorsal raphe nucleus and the ventral tegmental area, a brain region involved in reward and motivation. Their findings showed that this pathway played a role in controlling food-seeking behavior. When researchers activated the pathway in pregnant animals, food-craving-like behavior decreased. When the pathway was blocked in nonpregnant animals, the behavior increased. These results suggest that communication between these two brain regions may help control the desire to seek certain foods.
Together, the findings point to a possible chain of events in which pregnancy increases SK3 activity, reduces the activity of serotonin-producing nerve cells and changes signals within brain circuits involved in motivation and reward. These changes may help explain why food cravings can become stronger during pregnancy. Dr. He, director of the Brain Glycemic and Metabolism Control Laboratory at Pennington Biomedical, said the findings could eventually help researchers better understand why some women experience intense food cravings and excessive weight gain during pregnancy.
However, the research was conducted in mice, and the results cannot yet be assumed to apply directly to humans. Human studies will be needed to determine whether the same brain changes occur during pregnancy and whether they help explain differences in appetite and food preferences. The researchers also cautioned that directly changing serotonin activity during pregnancy could carry risks. Further work is needed to understand how pregnancy-related hormones and other body changes affect SK3 activity and serotonin signaling.
Although the findings do not provide a treatment for pregnancy cravings, they offer a closer look at the brain activity that may influence food motivation during pregnancy. Further research will be needed to determine whether these changes occur in people and how they may relate to maternal health.
Sources:
Study identifies brain mechanism behind pregnancy-related food cravings
Serotonin neurons in the dorsal raphe control food-craving-like behavior during pregnancy in mice
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