Sayegh, M., Henderson, J., Farquharson, A.J., Horgan, G.W., Ranawana, V. and Drew, J.E.
||Background: Research suggests green leafy vegetables (GLV) could help improve postprandial glycaemic responses (PGR) and metabolic health. However, inter-individual variations in metabolic responses preclude conclusive evidence. Gene expression profiling has been shown to be a useful tool in deciphering inter-individual variation.
Objective: This study aimed to investigate determinants of inter-individual variation in PGR in women co-ingesting GLV with a carbohydrate meal, focusing on markers of metabolic health and sirtuin system gene gene expression profiling.
Methods: In an acute randomized controlled crossover study, 31 women (BMI 24.8 - 30.5 kg/m2) were recruited (n=31). PGR responses for 4 hours post-consumption of rice (R) (75g available carbohydrate), rice with bok choy (RB) (150g) or spinach (RS) (150g) were measured using a Continuous Glucose Monitoring (CGM) system. Anthropometric, stress, physical activity, visual analogue scale questionnaires and gastric emptying (GE) rate measures were collected. Plasma insulin, adropin, lipids, oestradiol, progesterone, follicle-stimulating hormone (FSH) and testosterone were measured. Gene expression was measured using the GenomeLab System and a custom designed multiplex assay, the hSIRTNADPlex (25 targets involved in sirtuin signalling). Principal Component Analysis (PCA) and Partial Least Squares (PLS) were performed on the entire data set to identify patterns linked to PGR.
Results: Linear mixed model revealed no effect of GLV consumption on PGR. Correlation analysis showed PGR correlated with age, but no other consistent associations were observed. PCA revealed stratification of the cohort into two subgroups, based on hSIRTNADPlex gene expression profiles. PLS analysis revealed the stratified sub-groups were not associated with menopausal status or meal consumed. Notably, lower expression of sirtuin gene targets was associated with higher PGR, lipid, insulin, fat mass, waist/hip circumferences and lower adropin levels.
Conclusion: Co-ingesting GLV with a carbohydrate meal did not reduce postprandial GR in women. Variable responses were evident and largely independent of menopausal status and meal consumed, but partly attributed to sirtuin system variation and associated with markers linked to health status.
Keywords: postprandial glycaemia, inter-individual variation, sirtuins, adropin, green leafy vegetables, carbohydrates, women