Sodium elevates the plasma glucose response to glucose ingestion in man.

Active transport of glucose across the intestinal mucosa is dependent upon the presence of sodium in the gut lumen. While much information is available on the functional characteristics of this cotransport system, the role of sodium in the in vivo response to the ingestion of a glucose load has not been established. In the present study, two glucose solutions (87 g; Glucola), one containing 2.7 g sodium chloride (NaCl) and the other containing sufficient mannitol (87 mmol) to achieve the same osmolality, were administered orally to a group of 10 healthy subjects on separate days, and their plasma glucose responses were measured for 3.5 h after ingestion. Plasma glucose levels were significantly higher between 45–105 min of ingestion with NaCl than with mannitol, the mean difference being 19 mg/dl. The cumulative incremental glucose response was 7.3 ± 1.3 g/dl-210 min with NaCl and 5.7 ± 1.2 with mannitol (P < 0.01). The plasma insulin response to glucose plus NaCl was also significantly (P < 0.05) heighte...