(P09-006-25) Effect of Varying Protein Preload Content on Dorso-Lateral Prefrontal Cortex Activation as Assessed by Functional Near infra-Red Spectroscopy (fNIRS)

Objectives: Protein containing preloads are known to reduce subsequent food intake.  We postulated that one potential mechanism for this action of protein is mediated through increased dorso-lateral prefrontal cortex (dlpfc) activation, and hypothesized that dlpfc activity would exhibit greater activity (uMoxyhemoglobin) after consuming 8 grams of dairy protein compared to 1.2 grams of dairy protein.

Methods: Using a participant pool of convenience, we assessed dlpfc activation by functional near infra-red spectroscopy (fNIRS) 20 minutes after participants consumed either a dairy beverage containing 1.2 grams or 8 grams of dairy protein (Nasser et al 2022) each tested in a separate session.  Participants were then provided with ad libitum access to ultra-processed vanilla ice cream and kcals of ice cream eaten were determined.

Results: The caloric intake of ice cream 20 minutes after consuming preloads with varying dairy protein levels revealed significant differences in consumption and corresponding brain activity. Participants consumed more ice cream after a low-protein preload (217 ± 81 kcal) compared to a high-protein preload (174 ± 69 kcal, p = 0.004). Functional near-infrared spectroscopy (fNIRS) measurements showed decreased oxygenated hemoglobin (μM oxyhemoglobin) in the dorsolateral prefrontal cortex (dlPFC) following the low-protein preload (-0.15 ± 0.66), suggesting reduced inhibitory control. Conversely, the high-protein preload was associated with increased dlPFC activity (0.44 ± 0.77), indicating enhanced self-regulation (p = 0.033, 1-tailed, for the predicted increase in dlPFC activity). These findings emphasize the impact of dietary protein on both eating behavior and neural activity related to self-control.

Conclusions: This data demonstrates that the higher protein preload increased activation of dlpfc within the same time frame, and was associated with a lower intake of UPF. The data are consistent with a potential mechanism of protein satiety mediated through increased activation of the dorso-lateral prefrontal cortex.

Funding Sources: This project was funded by a Seed Grant from the Office of the Dean, College of Nursing and Health Professions, Drexel University to J.A.N.