Effect of Almond Consumption on the Neural Response in the Left Insula

Previous functional magnetic resonance imaging (fMRI) studies evaluating consummatory responses in the brain's taste and reward centers have been limited to liquid or semiliquid substances. The purpose of this study was to utilize fMRI to measure a consummatory response to solid foods in the left insula, which includes the primary taste cortex. Thirteen (12F/1M) subjects (BMI 30.8 ± 1.4 kg/m 2 , 36 ± 3.5 y) completed 2 fMRI sessions before (pre) and 2 after a 12wk weight loss intervention including 42g almonds daily (post). During each fMRI session, left insula activity was measured while subjects consumed either almonds or a eucaloric baked product (control). Palatability ratings were collected to evaluate the correlation between palatability and left insula activity. Palatability ratings were higher for almonds (78 ± 3 mm pre, 76 ± 7 mm post) compared to control (40 ± 6 mm pre, 48 ± 8 mm post) but ratings did not change following weight loss. Consumption of almonds and control caused significant activation in the left insula. Left insula activity was not different at pre vs. post‐weight loss while eating almonds. Alternatively, left insula activity was decreased while eating control post‐weight loss. There was a significant positive correlation between palatability rating and left insula activity for almonds (r=0.632, p=0.0086) but not for control (r=‐0.215, p=0.41). These data demonstrate the feasibility of measuring a consummatory response with fMRI while eating a solid food and suggest that the insula response was correlated with palatability ratings. Support: Almond Board of California, NIH UL1 TR001108, USDA (2011‐38420‐20038).