A Plant-Based Meal Affects Thalamus Perfusion Differently than an Energy- and Macronutrient-Matched Conventional Meal in Men with Type 2 Diabetes, Overweight/Obese, and Healthy Men: A Three-Group Randomized Crossover Study

Abstract

Background: Reward circuitry in the brain plays a key role in weight regulation. We tested the effects of a plant-based meal on these brain regions. Methods: A randomized crossover design was used to test the effects of two energy- and macronutrient-matched meals: a vegan (V-meal) and a conventional meat (M-meal) on brain activity, gastrointestinal hormones, and satiety in participants with type 2 diabetes (T2D; n=20), overweight/obese participants (O; n=20), and healthy controls (H; n=20). Brain perfusion was measured, using arterial spin labeling functional brain imaging; satiety was assessed using a visual analogue scale; and plasma concentrations of gut hormones were determined at 0 and 180 min. Repeated-measures ANOVA was used for statistical analysis. Bonferroni correction for multiple comparisons was applied. The Hedge's g statistic was used to measure the effect size for means of paired difference between the times (180-0 min) and meal types (M-V meal) for each group. Findings: Thalamus perfusion was the highest in patients with T2Dand the lowest in overweight/obese individuals (p=0.001). Thalamus perfusion decreased significantly after ingestion of the M-meal in men with T2D (p=0.04) and overweight/obese men (p=0.004), and it decreased significantly after ingestion of the V-meal in healthy controls (p<0.001). The effect size was -0.41 (95% CI, -1.14 to 0.31; p=0.26) for men with diabetes; -0.72 (95% CI, -1.48 to 0.01; p=0.05) for overweight/obese men; and 0.82 (95% CI, 0.09 to 1.59; p=0.03) for men with T2D. Changes in thalamus perfusion after ingestion of both test meals correlated with changes in satiety (r= +0.68; p<0.01), fasting plasma insulin (r= +0.40; p<0.01), C-peptide (r= +0.48; p<0.01) and amylin (r= +0.55; p<0.01), and insulin secretion at 5 mmol/l (r= +0.77; p<0.05). Interpretation: Thalamus perfusion decreased after the M-meal in men with T2D and overweight/obese men, and it decreased after the V-meal in healthy controls. The changes in thalamus perfusion were associated with changes in satiety and insulin secretion. Trial Registration: The trial is prospectively registered with ClinicalTrials.gov (ID: NCT02474147). Funding Statement: This work was supported by the project grant AZV15-27338A from Ministry of Health, Prague, Czech Republic and by the conceptual development of research organization („Institute for Clinical and Experimental Medicine – IKEM, IN 00023001“) from Ministry of Health, Czech Republic. Declaration of Interests: The authors stated: None declared Ethics Approval Statement: This study was approved by the Ethics Committee of the Thomayer Hospital and Institute for Clinical and Experimental Medicine in Prague, Czech Republic on August 13, 2014. The protocol identification number is G14-08-42.