Effects of Lentil Physical form and Digestive Enzyme Availability on Postprandial Mood Responses
Authors: Anguah Katherene O‐B , Campbell Wayne W , McCabe George P , McCrory Megan A 
Published: November 2023

BackgroundWe previously found that consuming a blended lentil meal reduced postprandial blood glucose response by 4.5±1.1 mg/dL compared with a no lentil control but did not differ from a whole lentil meal. Furthermore, when the enzyme supplement α‐galactosidase (α‐gal), which has the potential to accelerate blood glucose absorption by promoting oligosaccharide digestion in the small intestine, was taken with the meals, there were no significant interaction, or main effects on glucose response compared with a placebo. Since poor glucose control has been associated with negative mood and higher blood glucose has been linked with both positive and negative mood responses, we hypothesized that consumption of both blended and whole lentils or taking placebo will lead to better mood responses compared with a no lentil control or α‐gal respectively. Furthermore, the interaction effects of the lentil meals with α‐gal will reduce the positive mood responses compared with placebo.MethodsMood data were collected as part of a randomized crossover, double‐blind, placebo‐controlled trial of lentil physical form and α‐gal availability on glucose and appetite responses. Over a 3‐h period following the consumption of breakfast burritos containing ≥½ cup of cooked whole (W), blended (B) or no lentils (C), each in combination with 3 α‐gal or placebo pills subjects (n=12; BMI 23±3 kg/m2; aged 28±10 y (mean±SD)) rated the following mood responses: overall mood pleasantness, concentration, happiness, mental energy, physical fatigue, sleepiness, boredom, anxiety and irritability on a 9‐point rating scale.ResultsMixed model ANOVA showed the total AUC for overall mood pleasantness was higher for the α‐gal than the placebo (1179±42 vs. 1137±42, p=0.042, 4% difference). There were no main effects or interaction effects on AUC for any of the other mood variables. Consistent with the AUC results, analysis of changes over time in overall mood pleasantness also showed an effect of the enzyme supplement (p=0.001) such that α‐gal resulted in higher overall mood pleasantness compared with the placebo. The time course analysis for the other mood variables showed significant effects; in general, consumption of both blended and whole lentils lowered positive mood responses (concentration, mental energy and happiness) and increased negative mood responses (physical fatigue, anxiety and irritability) from baseline compared with the control (the magnitude of effects ranged from 5–11% on a 9 point scale). Alpha‐gal also generally resulted in increases in positive mood responses and decreases in negative mood responses. Also, mood differences across treatments were not associated with differences in blood glucose response.ConclusionsAlpha‐gal but not consumption of lentils resulted in favorable effects on mood responses in the postprandial state in our study. These effects did not appear to be mediated by changes in blood glucose.Support or Funding InformationUSDBC; NIH RR025761