The role of maternal BMI on brain food cue reactivity in children: a preliminary study

A systematic review of MRI studies on the effects of maternal obesity on offspring brain structure and function

Maternal obesity before or during pregnancy has been associated previously in offspring with a wide range of poor neurodevelopmental outcomes and mental health problems. The effects of maternal obesity on offspring brain structure and function that may be responsible for these poor outcomes are not well understood. We, therefore, undertook a systematic review of magnetic resonance imaging (MRI) studies that have assessed the associations of maternal obesity with brain measures in offspring. A systematic search was conducted in PubMed, Web of Science, Scopus, and PsycINFO on August 20, 2023. Of 15 eligible studies, seven employed functional MRI (fMRI), five diffusion tensor imaging (DTI), and four anatomical MRI (one used both DTI and anatomical MRI) in the offspring. The ages of offspring varied widely: one was a study of fetuses in utero, five of neonates, one of infants, five of school-aged children, two of both neonates and infants, and one of both children and adults. Collectively, 12 studies reported significant associations of maternal obesity with structural or functional alterations of the offspring's brain, most frequently in the prefrontal cortex and limbic system. In conclusion, maternal obesity appears to have a profound influence on offspring brain development, particularly within the prefrontal and limbic networks that regulate emotion and behavior. Further studies are needed to identify how changes in brain structure and function mediate the effects of maternal obesity on long-term emotional and behavioral outcomes, as well as the molecular pathways through which maternal obesity alters offspring brain development.

Does 'portion size' matter? Brain responses to food and non-food cues presented in varying amounts

Larger portions of food elicit greater intake than smaller portions of food, particularly when foods are high in energy density (kcal/g; ED). The neural mechanisms underlying this effect remain unclear. The present study used fMRI to assess brain activation to food (higher-ED, lower-ED) and non-food (office supplies) images presented in larger and smaller (i.e., age-appropriate) amounts in 61, 7-8-year-olds (29 male, 32 female) without obesity. Larger amounts of food increased activation in bilateral visual and right parahippocampal areas compared to smaller amounts; greater activation to food amount (larger > smaller) in this cluster was associated with smaller increases in food intake as portions increased. Activation to amount (larger > smaller) was stronger for food than office supplies in primary and secondary visual areas, but, for office supplies only, extended into bilateral parahippocampus, inferior parietal cortex, and additional visual areas (e.g., V7). Activation was greater for higher-vs. lower-ED food images in ventromedial prefrontal cortex for both larger and smaller amounts of food; however, this activation extended into left lateral orbital frontal cortex for smaller amounts only. Activation to food cues did not differ by familial risk for obesity. These results highlight potentially distinct neural pathways for encoding food energy content and quantity.

Influence of insulin sensitivity on food cue evoked functional brain connectivity in children

Objective

Insulin resistance during childhood is a risk factor for developing type 2 diabetes and other health problems later in life. Studies in adults have shown that insulin resistance affects regional and network activity in the brain which are vital for behavior, e.g. ingestion and metabolic control. To date, no study has investigated whether brain responses to food cues in children are associated with peripheral insulin sensitivity.

Methods

We included 53 children (36 girls) between the age of 7-11 years, who underwent an oral Glucose Tolerance Test (oGTT) to estimate peripheral insulin sensitivity (ISI). Brain responses were measured using functional magnetic resonance imaging (fMRI) before and after glucose ingestion. We compared food-cue task-based activity and functional connectivity (FC) between children with low and high ISI, adjusted for age and BMIz.

Results

Independent of prandial state (i.e., glucose ingestion), children with lower ISI showed higher FC between the anterior insula and caudate and lower FC between the posterior insula and mid temporal cortex than children with higher ISI. Sex differences were found based on prandial state and peripheral insulin sensitivity in the insular FC. No differences were found on whole-brain food-cue reactivity.

Conclusions

Children with low peripheral insulin sensitivity showed differences in food cue evoked response particularly in insula functional connectivity. These differences might influence eating behavior and future risk of developing diabetes.

Children at high familial risk for obesity show executive functioning deficits prior to development of excess weight status

OBJECTIVE

The objective of this study was to determine whether children with healthy weight who vary by familial risk for obesity differ in executive functioning.

METHODS

Children (age 7-8 years) without obesity (n = 93, 52% male) who differed by familial risk for obesity (based on maternal weight status) completed go/no-go and stop-signal tasks to assess inhibitory control and an N-back task to assess working memory. Dual energy x-ray absorptiometry measured adiposity. Linear and mixed-effect models assessed unique effects and relative importance analysis-quantified relative effects of familial risk and percent body fat.

RESULTS

Children at high compared with low familial risk showed worse inhibitory control; however, child adiposity was not associated with inhibitory control. Both high familial risk and greater child adiposity were associated with worse N-back performance when cognitive demand was high (2-back), but not low (0- and 1-back). The relative effect of familial risk on executive functioning was 2.7 to 16 times greater than the relative effect of percent body fat.

CONCLUSIONS

These findings provide initial evidence that deficits in executive functioning may precede the development of obesity in children at high familial risk for this disease. Additional family risk studies are needed to elucidate the pathways through which maternal obesity influences child executive functioning and risk for obesity.

Biobehavioral susceptibility for obesity in childhood: Behavioral, genetic and neuroimaging studies of appetite

Modern food environments are conducive to overeating and weight gain, but not everyone develops obesity. One reason for this may be that individuals differ in appetitive characteristics, or traits, that manifest early in life and go on to influence their behavioral susceptibility to gain and maintain excess weight. Classic studies showing that eating behavior in children can be measured by behavioral paradigms such as tests of caloric compensation and eating in the absence of hunger inspired the development and validation of psychometric instruments to assess appetitive characteristics in children and infants. A large body of evidence now suggests that food approach traits increase obesity risk, while food avoidant traits, such as satiety responsiveness, decrease obesity risk. Twin studies and genetic association studies have demonstrated that appetitive characteristics are heritable, consistent with a biological etiology. However, family environment factors are also influential, with mounting evidence suggesting that genetic and environmental risk factors interact and correlate with consequences for child eating behavior and weight. Further, neuroimaging studies are revealing that individual differences in responses to visual food cues, as well as to small tastes and larger amounts of food, across a number of brain regions involved in reward/motivation, cognitive control and other functions, may contribute to individual variation in appetitive behavior. Growing evidence also suggests that variation on psychometric measures of appetite is associated with regional differences in brain structure, and differential patterns of resting state functional connectivity. Large prospective studies beginning in infancy promise to enrich our understanding of neural and other biological underpinnings of appetite and obesity development in early life, and how the interplay between genetic and environmental factors affects appetitive systems. The biobehavioral susceptibility model of obesity development and maintenance outlined in this narrative review has implications for prevention and treatment of obesity in childhood.

How the placenta-brain lipid axis impacts the nutritional origin of child neurodevelopmental disorders: Focus on attention deficit hyperactivity disorder and autism spectrum disorder

Dietary fish is a rich source of omega-3 (n-3) fatty acids, and as such, is believed to have played an important role in the evolution of the human brain and its advanced cognitive function. The long chain polyunsaturated fatty acids, particularly the n-3 docosahexanoic acid (DHA), are critical for proper neurological development and function. Both low plasma DHA and obesity in pregnancy are associated with neurodevelopmental disorders such as attention deficit and hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in childhood, and n-3 supplementation has been shown to improve symptoms, as reviewed herein. The mechanisms underlying the connection between maternal obesity, n-3 fatty acid levels and offspring's neurological outcomes are poorly understood, but we review the evidence for a mediating role of the placenta in this relationship. Despite promising data that n-3 fatty acid supplementation mitigates the effect of maternal obesity on placental lipid metabolism, few clinical trials or animal studies have considered the neurological outcomes of offspring of mothers with obesity supplemented with n-3 FA in pregnancy.