Neural responses to food cues in middle to older aged adults: a scoping review of fMRI studies

The effect of hunger state on hypothalamic functional connectivity in response to food cues

The neural underpinnings of the integration of internal and external cues that reflect nutritional status are poorly understood in humans. The hypothalamus is a key integrative area involved in short- and long-term energy intake regulation. Hence, we examined the effect of hunger state on the hypothalamus network using functional magnetic resonance imaging. In a multicenter study, participants performed a food cue viewing task either fasted or sated on two separate days. We evaluated hypothalamic functional connectivity (FC) using psychophysiological interactions during high versus low caloric food cue viewing in 107 adults (divided into four groups based on age and body mass index [BMI]; age range 24-76 years; BMI range 19.5-41.5 kg/m² ). In the sated compared to the fasted condition, the hypothalamus showed significantly higher FC with the bilateral caudate, the left insula and parts of the left inferior frontal cortex. Interestingly, we observed a significant interaction between hunger state and BMI group in the dorsolateral prefrontal cortex (DLPFC). Participants with normal weight compared to overweight and obesity showed higher FC between the hypothalamus and DLPFC in the fasted condition. The current study showed that task-based FC of the hypothalamus can be modulated by internal (hunger state) and external cues (i.e., food cues with varying caloric content) with a general enhanced communication in the sated state and obesity-associated differences in hypothalamus to DLPFC communication. This could potentially promote overeating in persons with obesity.

The Association Between Food Addiction and Weight Status in School-Age Children and Adolescents

Background

The association between food addiction (FA) and weight status in children and adolescents remains poorly understood. This study aimed to elucidate the association between FA and weight status using the validated Chinese version of the dimensional Yale Food Addiction Scale for Children 2.0 (dYFAS-C 2.0).

Methods

Participants were enrolled from clinic visitors for regular physical check in a children's hospital. The dYFAS-C 2.0 was translated into Chinese and validated using reliability and validity tests. The participants' body mass index Z score (BMIZ) and waist-to-height ratio (WHtR) were used to characterize weight status. The FA severity was assessed using the translated dYFAS-C 2.0.

Results

Among the 903 children and adolescents enrolled, 426 (47.2%) completed the survey [277 (65%) females and 149 (35%) males]. The Cronbach α of translated dYFAS-C 2.0 was 0.934, and confirmatory factor analysis indicated an acceptable model fit. FA correlated positively with BMIZ and WHtR in the whole sample after adjusting for the effect of gender (p < 0.001). Further analyses showed that the correlation remained significant in participants with BMIZ > 1 (p = 0.006) but not in those with BMIZ ≤ 1 (p = 0.220). However, the correlations between FA and WHtR were statistically significant in both participants with or without abdominal obesity (p < 0.05). The FA could explain 12.1 and 15.8% of variance in BMIZ and WHtR, respectively. The corresponding cutoff points of FA for excessive weight risk were 0.7 (BMIZ) and 0.4 (WHtR).

Conclusion

The dYFAS-C 2.0 has good reliability and validity in the Chinese population. FA is associated with weight status characterized by BMIZ and WHtR, especially in participants with BMIZ > 1 and in those with abdominal obesity.

Clinical Trial Registration

[www.chictr.org.cn], identifier [ChiCTR2100052239].