Relationship between glycaemic index and nutrient composition of fruit and vegetables

The glycaemic index (GI) of different fruits and vegetables varies over a three-fold range but no causal explanation for the differences has been advanced. This study examined the statistical relationship between published data on GI and the concentrations of nutrients in 24 fresh fruit and vegetables. The most significant relationships were a decrease in GI with increasing organic acids, especially malic acid, and the monosaccharides glucose and fructose, and an increase in GI with increasing minerals. There was no significant correlation with sucrose, starch, citric acid, protein, fat or vitamin C. Possible part explanations for the findings is the GI is reduced by compositional changes that result in an increase in osmolality and nutrient concentration which delay gastric emptying. It is also suggested that acidity per se, i.e. pH, may have a direct effect on GI.