Image Sciences Institute, University Medical Center Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands.
The Rowett Institute, University of Aberdeen, Foresterhill Road AB25 2ZD, Scotland; Division of Biomedical Sciences, Centre for Health Science, University of the Highlands and Islands, Inverness IV2 3JH, United Kingdom.
Neuroimage. 2021 Oct 15;240:118374. doi: 10.1016/j.neuroimage.2021.118374. Epub 2021 Jul 7.
Food cue exposure can trigger eating. Food cue reactivity (FCR) is a conditioned response to food cues and includes physiological responses and activation of reward-related brain areas. FCR can be affected by hunger and weight status. The appetite-regulating hormones ghrelin and leptin play a pivotal role in homeostatic as well as hedonic eating. We examined the association between ghrelin and leptin levels and neural FCR in the fasted and sated state and the association between meal-induced changes in ghrelin and neural FCR, and in how far these associations are related to BMI and HOMA-IR. Data from 109 participants from three European centers (age 50±18 y, BMI 27±5 kg/m) who performed a food viewing task during fMRI after an overnight fast and after a standardized meal were analyzed. Blood samples were drawn prior to the viewing task in which high-caloric, low-caloric and non-food images were shown. Fasting ghrelin was positively associated with neural FCR in the inferior and superior occipital gyrus in the fasted state. This was partly attributable to BMI and HOMA-IR. These brain regions are involved in visual attention, suggesting that individuals with higher fasting ghrelin have heightened attention to food cues. Leptin was positively associated with high calorie FCR in the medial prefrontal cortex (PFC) in the fasted state and to neural FCR in the left supramarginal gyrus in the fasted versus sated state, when correcting for BMI and HOMA-IR, respectively. This PFC region is involved in assessing anticipated reward value, suggesting that for individuals with higher leptin levels high-caloric foods are more salient than low-caloric foods, but foods in general are not more salient than non-foods. There were no associations between ghrelin and leptin and neural FCR in the sated state, nor between meal-induced changes in ghrelin and neural FCR. In conclusion, we show modest associations between ghrelin and leptin and neural FCR in a relatively large sample of European adults with a broad age and BMI range. Our findings indicate that people with higher leptin levels for their weight status and people with higher ghrelin levels may be more attracted to high caloric foods when hungry. The results of the present study form a foundation for future studies to test whether food intake and (changes in) weight status can be predicted by the association between (mainly fasting) ghrelin and leptin levels and neural FCR.
食物线索暴露会引发进食。食物线索反应(FCR)是对食物线索的条件反应,包括生理反应和与奖励相关的大脑区域的激活。FCR 会受到饥饿和体重状况的影响。调节食欲的激素胃饥饿素和瘦素在稳态和享乐性进食中起着关键作用。我们研究了空腹和饱腹状态下胃饥饿素和瘦素水平与神经 FCR 之间的关系,以及餐后胃饥饿素变化与神经 FCR 之间的关系,以及这些关系与 BMI 和 HOMA-IR 的关系。该研究的数据来自三个欧洲中心的 109 名参与者(年龄 50±18 岁,BMI 27±5kg/m),他们在禁食一夜后和标准餐后进行 fMRI 食物观察任务。在观看任务之前抽取血液样本,其中显示高热量、低热量和非食物图像。空腹胃饥饿素与禁食状态下下顶叶和上顶叶的神经 FCR 呈正相关。这部分归因于 BMI 和 HOMA-IR。这些大脑区域参与视觉注意力,这表明空腹时胃饥饿素水平较高的个体对食物线索的注意力更高。瘦素与禁食状态下内侧前额叶皮质(PFC)的高热量 FCR 呈正相关,与禁食状态下左侧缘上回的神经 FCR 呈正相关,当分别校正 BMI 和 HOMA-IR 时。这个 PFC 区域参与评估预期的奖励价值,这表明对于瘦素水平较高的个体,高热量食物比低热量食物更突出,但食物并不比非食物更突出。在饱腹状态下,胃饥饿素和瘦素与神经 FCR 之间没有相关性,餐后胃饥饿素变化与神经 FCR 之间也没有相关性。总之,我们在一个相对较大的、年龄和 BMI 范围较广的欧洲成年人样本中,发现了胃饥饿素和瘦素与神经 FCR 之间的适度关联。我们的研究结果表明,对于体重状况,瘦素水平较高的人,以及饥饿时胃饥饿素水平较高的人,可能更容易被高热量食物所吸引。本研究的结果为未来的研究奠定了基础,这些研究可以测试(主要是空腹)胃饥饿素和瘦素水平与神经 FCR 之间的关联是否可以预测食物摄入和(体重状况的)变化。