Fearnbach S Nicole, English Laural K, Lasschuijt Marlou, Wilson Stephen J, Savage Jennifer S, Fisher Jennifer O, Rolls Barbara J, Keller Kathleen L
Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA.
Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands.
Physiol Behav. 2016 Aug 1;162:3-9. doi: 10.1016/j.physbeh.2016.03.007. Epub 2016 Mar 10.
Energy balance is regulated by a multifaceted system of physiological signals that influence energy intake and expenditure. Therefore, variability in the brain's response to food may be partially explained by differences in levels of metabolically active tissues throughout the body, including fat-free mass (FFM) and fat mass (FM). The purpose of this study was to test the hypothesis that children's body composition would be related to their brain response to food images varying in energy density (ED), a measure of energy content per weight of food. Functional magnetic resonance imaging (fMRI) was used to measure brain response to High (>1.5kcal/g) and Low (<1.5kcal/g) ED food images, and Control images, in 36 children ages 7-10years. Body composition was measured using bioelectrical impedance analysis. Multi-subject random effects general linear model (GLM) and two-factor repeated measures analysis of variance (ANOVA) were used to test for main effects of ED (High ED vs. Low ED) in a priori defined brain regions of interest previously implicated in energy homeostasis and reward processing. Pearson's correlations were then calculated between activation in these regions for various contrasts (High ED-Low ED, High ED-Control, Low ED-Control) and child body composition (FFM index, FM index, % body fat). Relative to Low ED foods, High ED foods elicited greater BOLD activation in the left thalamus. In the right substantia nigra, BOLD activation for the contrast of High ED-Low ED foods was positively associated with child FFM. There were no significant results for the High ED-Control or Low ED-Control contrasts. Our findings support literature on FFM as an appetitive driver, such that greater amounts of lean mass were associated with greater activation for High ED foods in an area of the brain associated with dopamine signaling and reward (substantia nigra). These results confirm our hypothesis that brain response to foods varying in energy content is related to measures of child body composition.
能量平衡由一个影响能量摄入和消耗的多方面生理信号系统调节。因此，大脑对食物反应的变异性可能部分由全身代谢活跃组织水平的差异来解释，包括去脂体重（FFM）和脂肪量（FM）。本研究的目的是检验这样一个假设，即儿童的身体组成与其大脑对能量密度（ED，即每单位重量食物的能量含量）不同的食物图像的反应有关。功能性磁共振成像（fMRI）用于测量36名7至10岁儿童对高能量密度（>1.5千卡/克）和低能量密度（<1.5千卡/克）食物图像以及对照图像的大脑反应。使用生物电阻抗分析测量身体组成。多受试者随机效应一般线性模型（GLM）和双因素重复测量方差分析（ANOVA）用于在先验定义的、先前与能量稳态和奖赏处理有关的大脑感兴趣区域中检验能量密度（高能量密度与低能量密度）的主要效应。然后计算这些区域在各种对比（高能量密度-低能量密度、高能量密度-对照、低能量密度-对照）下的激活与儿童身体组成（FFM指数、FM指数、体脂百分比）之间的皮尔逊相关性。相对于低能量密度食物，高能量密度食物在左侧丘脑引起更大的血氧水平依赖（BOLD）激活。在右侧黑质，高能量密度-低能量密度食物对比的BOLD激活与儿童FFM呈正相关。高能量密度-对照或低能量密度-对照对比没有显著结果。我们的研究结果支持了将FFM作为食欲驱动因素的文献，即更多的瘦体重与大脑中与多巴胺信号和奖赏有关区域（黑质）对高能量密度食物的更大激活相关。这些结果证实了我们的假设，即大脑对能量含量不同的食物的反应与儿童身体组成的测量有关。
