Researchers from Baylor College of Medicine recently discovered that mice overfed from the first few weeks of life became sluggish and obese as compared to their normally fed counterparts, which were more active and less prone to obesity. According to the journal online journal Diabetes, the cause of this was epigenetic changes to DNA in the brain.
To test this, Dr. Robert Waterland, associate professor of pediatrics – nutrition at BCM and a scientist in the USDA/ARS Children’s Nutrition Research Center at Baylor College of Medicine and Texas Children’s Hospital, together with his colleagues observed mice that were suckled in small groups and compared them to mice suckled in normal sized groups.
The mice in the smaller groups had easier access to the mother’s milk, and took advantage of it. In turn, they gained more weight and became fatter than the others and continued that way into adulthood, even though all mice were fed the same type and amount of food after weaning.
Detailed metabolic studies of the adult female mice showed, surprisingly, that those that had been over-nourished as infants did not eat more than their lean counterparts. Instead, they remained fatter as adults because they were much less physically active.
This was emphasised in a statement made by Waterland on BCM:
“Overnutrition in infancy is causing persistent changes that last into adulthood. These could mediate the persistent changes in physical activity.”
Furthermore, the researchers found out using special DNA genomic procedures that there were significant changes in DNA methylation (a post-genetic or epigenetic change) in the hypothalamus area of the brain during infancy (the hypothalamus is a key region for regulation of body weight). Although the individual methylation changes were small, overall they had a profound effect in influencing the risk for obesity, physical activity and sluggish behavior.