Gigliola Alberti¹, Javier Parada², L. Rodrigo Cataldo³, Javier Vega³, Concepción M. Aguilera⁴, Ana I. Alvarez-Mercado⁴, M. Isabel Hodgson^{1, 3}, Alberto López³, Isidora Angellotti³, Angel Gil⁴, José L. Santos^3,

Salivary amylase activity is partially determined by genetic factors and is possibly related with postprandial plasma glucose levels. The aim of this study is to evaluate the association of salivary amylase activity with plasma glucose and insulin levels after consumption of a gelatinized starchy model food (80% amylopectin; 70% gelatinization), as well as to assess the influence of the salivary amylase gene (AMY1) copy-number variation in amylase activity and concentration. Our results show a strong and significant relation between copy-number variation of AMY1 gene measured through qPCR with salivary amylase concentration, with an enhanced correlation with amylase activity when corrected by salivary flow (r = 0.83, P-value = 0.003). Subjects with high salivary amylase activity tend to have a higher early increase in plasma insulin concentration and a lower glycemic response after starch ingestion compared to subjects with low salivary amylase activity, although these observations did not achieve statistical significance (r = 0.41; P-value = 0.23). In conclusion, we found a strong association between copy-number of AMY1 gene with salivary amylase activity and concentration. However, we did not find evidences for a major role of salivary amylase activity on glycemic response after starch consumption.

amylase, copy number variation, starch, glycemic response