Effects of Buckwheat, Potato and Rice on Glycemic Indices in Healthy Subjects

We compared the long-term metabolic effects of equal amounts of carbohydrate from potato, rice and buckwheat on glycemic indices and blood lipids in healthy subjects. Nine healthy volunteers-2 men and 7 women were studied. All subjects ate diets based on the same-7-day rotating menu differing only in that the major source of carbohydrate (about 50% of daily total calories) came either from buckwheat, rice or potato. The study was conducted with a triple crossover design over three 7 day periods. On the morning of the 8th day, fasting blood was drawn from each subject to determine serum glucose, insulin, triglycerides, total and HDL-cholesterol. Subjects were then asked to eat breakfast with their respective carbohydrate within a 20 min period. Blood samples were drawn at 30, 60, 120 and 180 min after the start of breakfast to determine glucose and insulin levels. At 30 min the glucose response to the rice meal(7.15mmol/L) and potato meal(6.71mmol/L) were greater than the response to the buckwheat meal(5.855mmol/L) (P < 0.05). The mean area under the glucose response to the curve following the rice meal was greater than that following the buckwheat meal(P < 0.05). The insulin responses to the potato and rice meals at 30 and 60 min were greater than those to the buckwheat meal (P < 0.05). The mean area under the serum insulin response curve after the rice meal was greater than of buckwheat. Blood lipids, uric acid and glycosylated hemoglobin were not affected by the three meals. The study shows that the buckwheat meal has more beneficial effects on glycemic indices than either the rice meal or potato meal in healthy subjects.