- Epidemiological studies have consistently found that obese parents often raise obese children.
- An imaging study showed that a mother’s degree of obesity is correlated with her child's inadequate activation of self-regulatory brain circuits.
- Impaired responses of two critical brain regions may increase the risk of childhood obesity and explain intergenerational obesity.
Many factors contribute to childhood obesity, including, genetic (and epigenetic) predisposition, a social trend towards higher caloric intake, and parental obesity. Epidemiological studies have consistently found that obese parents often raise obese children.
Recent studies have examined the potential biological mechanisms underlying the intergenerational transmission of obesity. Many obesity-related genes, inherited from both parents, are preferentially expressed in brain regions responsible for the self-regulation of food-seeking behaviors, particularly highly rewarding foods. Two of the most important brain regions that contain this self-regulation circuitry are the dorsal lateral prefrontal cortex and anterior cingulate gyrus.
Parental obesity and self-regulation
A recent study considered whether a child’s prenatal exposure to parental obesity affected the normal function of the brain’s self-regulation circuitry. The scientists investigated the relationship between paternal BMI, maternal BMI (both pre-pregnancy and current), and the reactivity of specific brain regions to food cues in 76 healthy children aged 7 to 11 years old (28 males, 48 females; 89.5% were prepubertal; 63.2% were of normal weight, 11.8% overweight, and 25% obese). The scientists wanted to determine whether the obesity-related genes inherited from an obese father or mother were primarily responsible for the altered activity in the self-regulation circuitry in their child’s brain.
Similar to the findings of previous studies, if one parent was obese, both were obese; in addition, the child of the obese parents was obese as well. Maternal BMI ranged from 19.63 to 58.85; paternal BMI ranged from 22.60 to 46.99. Paternal BMI was significantly related to maternal BMI, and both were significantly correlated with their child’s BMI.
Functional Magnetic Resonance Imaging studies of the children revealed, as expected, that the activity of the dorsal lateral prefrontal cortex and anterior cingulate gyrus was the most responsive to food cues. The results of the imaging study demonstrated that the mother’s degree of obesity was significantly correlated with inadequate activation of the self-regulation brain regions in her children. The father’s degree of obesity had no effect on the response of these brain regions.
Why are these findings important? Ordinarily, the dorsal lateral prefrontal cortex and anterior cingulate gyrus regulate our dietary self-control. Their job is to inhibit our urge to eat tasty foods that contain fat, salt, and sugar. This study indicates that the children of obese mothers inherit a brain whose self-regulation circuits may not react appropriately to rewarding food cues. The impaired responses of these two critical regions may increase the risk of childhood obesity and explain the intergenerational incidence of obesity.
Wenk GL (2019) Your Brain on Food, 3rd Ed (Oxford University Press).
Luo S et al (2021) The role of maternal BMI on brain food cue reactivity in children. Brain Imaging & Behavior 15 (6), p.2746.