The apéritif effect: Alcohol's effects on the brain's response to food aromas in women

Abstract

Objective: Consuming alcohol prior to a meal (an apéritif) increases food consumption. This greater food consumption may result from increased activity in brain regions that mediate reward and regulate feeding behavior. Using functional magnetic resonance imaging, we evaluated the blood oxygenation level dependent (BOLD) response to the food aromas of either roast beef or Italian meat sauce following pharmacokinetically controlled intravenous infusion of alcohol.

Methods: BOLD activation to food aromas in non-obese women (n = 35) was evaluated once during intravenous infusion of 6% v/v EtOH, clamped at a steady-state breath alcohol concentration of 50 mg%, and once during infusion of saline using matching pump rates. Ad libitum intake of roast beef with noodles or Italian meat sauce with pasta following imaging was recorded.

Results: BOLD activation to food relative to non-food odors in the hypothalamic area was increased during alcohol pre-load when compared to saline. Food consumption was significantly greater, and levels of ghrelin were reduced, following alcohol.

Conclusions: An alcohol pre-load increased food consumption and potentiated differences between food and non-food BOLD responses in the region of the hypothalamus. The hypothalamus may mediate the interplay of alcohol and responses to food cues, thus playing a role in the apéritif phenomenon.

Figure 1

Subjective Effects of Alcohol as reported both pre- and during alcohol and saline infusion sessions. T0 = Pre-Infusion baseline; T1 – T5 = Intra-Infusion assessments. Intensity (FO=12.2, SE=1.0; IEd=12.1, SE=0.9), pleasantness (FO = 7.0±0.2; IEd = 7.6±0.2), and representativeness (FO = 6.8±0.2; IEd = 7.6±0.2) (for details, see Methods).

Figure 2. Circulating Ghrelin

Mean circulating ghrelin pre- and post-intravenous infusion of either alcohol or saline, with ghrelin showing a marked reduction following alcohol administration. †, p < 0.001.

Figure 3

A.) Olfactory response (both infusates and odors) in amygdala/piriform, and lateral orbitofrontal cortex. B.) Food Odor (FO) > Odor of Inedible object (IEd): Activation in anterior cingulate/medial prefrontal regions (sagittal view), amygdala/piriform and ventral striatum (coronal and axial), right orbitofrontal cortex and bilateral insula (axial). Display threshold p_uncorr < 0.001. The colorbar scales indicate t-statistic values for 35 subjects.

Figure 4

A.) Alcohol's Effect on Food Odor BOLD Response [FO > IEd] _{Alcohol > Saline} in the hypothalamus for all subjects (n=35). B.) Plots of mean BOLD responses for all subjects occurring within the Saline and Alcohol infusion sessions as extracted from the functional cluster (Table 2; p_uncorr < 0.005; yellow) in Panel A. C.) Differential Odor Response [FO > IEd]_Alcohol in the Hypothalamus in 13 AEM subjects. D.) 3-Way Interaction BOLD Response AEM>AEL [FO > IEd] _{Alcohol > Saline} in the Hypothalamus/Thalamus in 25 subjects. Display threshold, p_uncorr < 0.005 (yellow), Red color illustrates peak voxel-wise effect, p_uncorr ≥ 0.001. FO = Food Odors; IEd = Inedible Object Odors; AEM = Alcohol Eat More; AEL = Alcohol Eat Less.