Effects of green-leafy vegetable intake on postprandial glycemic and lipidemic responses and α-tocopherol concentration in normal weight and obese men.

Vegetable consumption has been encouraged as a component of nutritional education for obese and insulin-resistant patients. However, the benefits of vegetable intake in a therapeutic diet on postprandial glycemic and lipidemic responses have not been clarified. We studied the effects of the intake of spinach, a green-leafy vegetable rich in dietary fiber and α-tocopherol, with a fat-rich meal on postprandial glycemic and lipidemic changes. Fourteen normal weight and 10 obese men consumed three test meals of bread, as a control, bread and butter, and bread and butter with boiled spinach. Blood samples were obtained prior to and 30, 60, 120, 180 and 240 min after consuming the test meals. Compared with the bread meal, consumption of the bread and butter meal showed a reduced peak glucose response at 30 min in normal (p<0.05) but not in obese subjects. The increase in triglyceride and decrease in LDL-cholesterol were greater after the butter-containing meal than after the bread meal (p<0.05). The α-tocopherol/lipid level decreased and remained low after the bread and butter meal, but the decrease was smaller with the spinach-containing meal in obese subjects (p<0.05). These results suggest that green-leafy vegetable intake with a fat-rich meal is effective for supplying postprandial α-tocopherol in obese subjects, but consumption of a regular-sized dish cannot be expected to improve abnormal postprandial hyperglycemic or hyperlipidemic responses.