Eating to dare - Nutrition impacts human risky decision and related brain function

Area of Science:

• Neuroscience
• Nutritional Science
• Behavioral Economics

Background:

• Macronutrient intake influences plasma amino acid profiles, which are precursors to neurotransmitters affecting brain function and decision-making.
• Serotonin, a key neurotransmitter, regulates both appetite and economic choices, highlighting the link between nutrition and behavior.

Purpose of the Study:

• To investigate how acute nutritional manipulation, specifically altering the carbohydrate/protein ratio of a meal, affects plasma tryptophan levels and subsequent risky decision-making.
• To explore the neural mechanisms underlying nutrition-driven changes in risk propensity using functional magnetic resonance imaging (fMRI).

Main Methods:

• Participants consumed breakfasts with varying carbohydrate/protein ratios.
• Plasma amino acid levels, particularly the tryptophan/large neutral amino acids (LNAA) ratio, were measured.
• Risky decision-making tasks were administered, alongside fMRI to monitor brain activity, specifically in the parietal lobule.

Main Results:

• A high-carbohydrate/protein breakfast significantly increased the plasma tryptophan/LNAA ratio.
• This increase in the tryptophan/LNAA ratio correlated with changes in individual risk propensity.
• Parietal lobule activation during risk processing was sensitive to tryptophan/LNAA fluctuations and modulated by body fat mass, predicting behavioral changes.

Conclusions:

• Acute dietary interventions can modulate neurotransmitter precursors, leading to significant changes in human risky decision-making.
• Individual differences, such as body fat mass, play a role in mediating the effects of nutrition on risk propensity.
• Neural activity in the parietal lobule serves as a biomarker for nutrition-driven modulation of risk-taking behavior.