Brain dopamine responses to ultra-processed milkshakes are highly variable and not significantly related to adiposity in humans

Abstract

Ultra-processed foods high in fat and sugar may be addictive, in part, due to their purported ability to induce an exaggerated postingestive brain dopamine response akin to drugs of abuse. Using standard [¹¹C]raclopride positron emission tomography (PET) displacement methods used to measure brain dopamine responses to addictive drugs, we measured postingestive striatal dopamine responses to an ultra-processed milkshake high in fat and sugar in 50 young, healthy adults over a wide body mass index range (BMI 20-45 kg/m²). Surprisingly, milkshake consumption did not result in significant postingestive dopamine response in the striatum (p=0.62) nor any striatal subregion (p>0.33) and the highly variable interindividual responses were not significantly related to adiposity (BMI: r=0.076, p=0.51; %body fat: r=0.16, p=0.28). Thus, postingestive striatal dopamine responses to an ultra-processed milkshake were likely substantially smaller than many addictive drugs and below the limits of detection using standard PET methods.

Keywords: Obesity; PET; [11C]raclopride; controlled-feeding; dopamine; striatum; ultra-processed.

Figure 1.

(A) An ultra-processed milkshake did not significantly impact [¹¹C]raclopride binding potential (D2BP_ralco) across the whole sample (n=50) in whole striatum. (B) Distribution of percent change between fasting D2BP_ralco and D2BP_ralco after consumption of milkshake, with individuals displaying dopamine release (green, left, “Responders”, n=29) and those who did not (purple, right, “Non-responders”, n=21). (C) Those classified as milkshake “Responders” rated the milkshake as more pleasant (0=“neutral”, 100=“extremely pleasant”) (D) and reported greater wanting (0=“I don’t want any more”, 100=“I want much more of the milkshake”) (E) but similar levels of hunger after an overnight fast compared to “Non-responders

Figure 3.. Postingestive dopamine responses to milkshake correlated with prior fasting hunger and subsequent ad libitum cookie energy intake.

(A) Region of interest (ROI) analyses indicate that self-reported hunger after an overnight fast correlated with dopamine response to milkshake consumption, particularly in the left putamen. (B) The ROI relationship between hunger and dopamine response, was supported by voxelwise correlation analysis which identified two clusters surviving correction for multiple comparisons (left putamen: 106 voxels; x = 22.8, y=−6.0, z= 13.5; p<0.01; and right caudate: 39 voxels; x = –15.8, y = −20.0, z = 6.5; p<0.05). (C) Additionally, ROI analyses indicate that the postingestive dopamine response to milkshake particularly in the left putamen was correlated with ad libitum intake of energy from cookies at a subsequent meal test in the overnight fasted state. (D) Voxelwise analyses identified clusters in bilateral putamen surviving correction for multiple comparisons where dopamine response was correlated with subsequent ad libitum cookie consumption (left putamen: 41 voxels, x = 29.8, y= 11.5, z= 6.6; p<0.02; right putamen: 34 voxels, x = 26.2, y= 11.5, z= 6.5; p=0.05). All clusters defined by NN=1 (faces touching), k_e=20, bi-sided p_uncorr<0.1, and cluster corrected at p<0.05