Modulation of postprandial glycaemia and insulinaemia by dietary fat

The present study was designed to examine the effect of corn oil (Co) on postprandial glycaemia and insulinaemia when ingested with glucose (G), casein (Cs), cellulose (Cl) and pectin (P) in various combinations. The study was conducted on six healthy male volunteers, on each of whom six meal tolerance tests were performed. The meals were isocaloric and consisted of G; G and Co; G, Co and Cs; G, Co and P; G, Co, Cs and P; and G, Co, Cs and Cl. The meals were administered after an overnight fast. In addition to a fasting blood sample, blood was collected 0.5, 1.0, 1.5 and 2.0 h after ingestion for measurement of serum glucose and insulin levels. The glycaemic response to GCo was comparable to that to G, but the insulinaemic response was significantly lower. The glycaemic response to GCoCs was significantly lower than that to G but the insulinaemic response to both was comparable. The cellulose containing meal GCoCsCl showed a further reduction in the glycaemic response but not in the insulinaemic response. The pectin containing meals GCoP and GCoCsP gave the lowest glycaemic and insulinaemic responses, the responses to the latter being lower. Corn oil by itself has only a modest effect on the postprandial metabolic response to glucose. Addition of protein and fibre, specially pectin, leads to significant attenuation of glycaemic and insulinaemic responses.