Effects of commonly consumed traditional fortified staple meals on the postprandial blood glucose responses of undergraduate students in Imo State University, Owerri, Imo State, Nigeria: an open-label study

Abstract

Background: Diabetics Mellitus a chronic metabolic disorder that prevents the body to utilize glucose completely or partially requires low caloric diets. Unfortunately, Nigerian traditional menu is based on starchy foods. Many diabetic individuals had been ignorantly oriented to consume some staple foods that are believed to have lower calorie than others for low blood glucose response.The study is focused on determining the glycemic index of commonly consumed fortified staple foods as well as determining the extent of their effects on the postprandial blood glucose responses of undergraduate students.Methods: Fifteen volunteered non- diabetic undergraduate students aged 20 – 25yrs on which standard oral glucose tolerate test was performed were selected and were asked to report at the study centre each day after overnight fasting (10 – 12hrs) with certain precautions by 8am for a period of 5days for different prepared test meals from the commonly consumed fortified staple food; namely; beans stew, rice stew, yam stew, unripe plantain stew and garri and stew. Fasting blood samples (2ml each) were collected from the prominent arm veins of each student prior to the eating of one of the test meals on each day. Each test meal contains 50g carbohydrate portion per meal. After the meals had been eaten, 2ml venous blood samples were collected at 30minutes interval for 120 minutes each day from each student and put into the specimen bottles for blood glucose estimations. Also the random sugar was determined 2hours later. A glucometer was used for measuring the blood sugar using test strips. The mean values of postprandial glucose blood sugar for each test meals for the selected students were obtained.Results: The glycemic index of the commonly consumed fortified staple test meals was highest in rice stew (107.7± 8.4), followed by yam stew (102.4±1.8), garri and stew (101.4±11.8), beans stew (86.9±6.7), and unripe plantain stew (81.8±8.4) in that order. The carbohydrate content of the commonly consumed fortified staple test meals was highest in garri with soup (68.2±0.2g) and lowest in unripe plantain stew while the fibre content was highest in plantain stew (5.8±0.4g) and lowest in rice stew (2.8±0.12g). The mean blood oral glucose tolerance test of the students was below 100mg/dl but has the mean peak after an hour interval (112.8±7.3mg/dl) the test food meals were ingested.The highest increase on the postprandial blood glucose after ingestion of the test meals was highest for garri and stew test meal (97.2±14.7mg/dl) but lowest for unripe plantain stew meal (85.574.3±11.6mg/dl) after 60 minutes the test meals were ingested.The random blood sugar test was highest in garri and soup (93.1±2.4mg/dl), followed by beans stew (88.4±4.9mg/dl), and lowest in plantain stew (74.3±11.6mg/dl) test meals after 2hrs the test meals were ingested.Conclusion: Unripe plantain stew meal had the lowest glycemic index response, with lowest postprandial blood glucose response after for the period of time the test meal were ingested.. This could be attributed to the relatively higher level of fibre content of the unripe plantain than other test meals.Key Words: glycemic index, postprandial blood glucose concentrations, glucose tolerance test