The Glycemic Index - Report Example

Glyceamic Index By Insert Your Name Presented to Instructor’s Name, Course Institution Name, Location Date Due Glyceamic Index Abstract The tables of Glycemic Index tables which have been derived scientifically are very helpful in evaluating the relationship between Glycemic Load, Glycemic Index, and health. They are in particular used in the nutritional filed thus expounding more on the physiological effects of carbohydrates foods and their effects on food. However, different foods have different GI values and it is in this respect that six types of test foods were assessed. The experiment aimed practically proving the GI classification of these types of on documented literature. In this research paper, the experiment is explained to detail. Background Glycemic index is numerical a method used to rank food especially carbohydrates on a scale ranging from 0 to 100 in respect to which they induce an increase in the levels of blood glucose after their consumption. Values between 0 to 55, 56 to 69, and 70 or more represent low, moderate, and high GIs respectively. In order to asses the level of GI, blood samples are taken every 15 minutes after consumption of test food for evaluation. The results are then calculated using AUC method and consequently plotted on graph fro comparison with the reference food. Generally, Glycemic Index depicts the quality of the carbohydrates as it compares the same quantities of the carbohydrates hence not facilitate in establishing the quantity of food consumed. Conversely, to fully understand the effects of food on blood glucose, the concept of Glycemic Load was introduced by researchers in 1997. Glycemic load quantifies comprehensive Glycemic effects for a particular food portion.).’ The use of GI to classify carbohydrate rich foods was approved by a committee of experts in 1997 that had brought together FAO and WHO. According to David et al. (2001), ‘The glycemic index is the indexing of the glycemic response of a fixed amount of available carbohydrate from a test food to the same amount of available carbohydrate from a standard food consumed by the same subject (p. 266)’.. Furthermore, the Brand-Miller et al. 2001 argues that Glycemic load is used alongside GI to asses the total GI effect of the consumed diet especially in epidemiological research studies. A number of factors influence Glycemic Index and they include type of starch, physical entrapment, and viscosity of the fiber, sugar content, fat and protein content, acid content, food processing, and cooking method. Methods of Evaluation Subjects Six volunteers and healthy individuals consisting of different ages, sex, and weights w8ere recruited for this experiment. In the selection criteria the major determinants absence of symptoms or clinical signs of a chronic disease via laboratory analyses and physical examination, not dieting in the three-months previous period, not under any medication, sedentary lifestyle, ‘normal oral glucose tolerance test to rule out diabetes and glucose intolerance and normal fating lipid profile’ (José et al. 2006 p. 2). All the volunteers consented to terms and conditions of this study. Experimental design The time (hours) the subjects had last taken any meal was recorded and they were also subjected to twelve-hours fasting period prior to being provided with the test foods. After the fasting period, their blood samples were taken followed by provision of different test foods. Blood samples were taken after a regular interval of fifteen minutes for a period of one and a half hours. Experimental Foods The experimental test foods were Apple, Chocolate, Dates, Ryvita, Mars Bar, and Jelly Beans and they were provided in portions of 50 grams. The test foods differed in terms of type carbohydrate (low, moderate, and high GI) according to documented research. Therefore, the following test foods were administered: apple (low GI), chocolate (low GI), dates (high GI), ryvita (medium GI), mars bar (medium GI), and jelly beans (high GI). Blood Sample Analyses Venous blood samples for glucose were collected, from each of the volunteers, in glass tubes and coagulated on ice for about 10 minutes. Afterwards, serum was separated at room temperature and then stored at -20oc until analysis. Subsequently, serum glucose was analyzed using glucose oxidase method. There followed the assessment of serum glucose response by applying the incremental (iAUC) method and the total area under the curve (tAUC) methods at ¼ hours and 1 ½ hours, and between ¼ and 1 ½ hours. iAUC and tAUC were calculated geometrically by making use of trapezoidal rule. Results All the volunteers completed the one and a half hours experimental study. The collected blood samples, at an interval of 15 minutes after consumption of test foods were analyzed for glucose levels. The following raw data as obtained and for the purpose of experimental errors, the most reasonable and consistent values were taken for final graphical analysis. Raw Data BGL (mmol/L) Sex (M/F) Age Time(hrs) since last ate GI category Fasting 15 min 30min 45 min 60 min 75 min 90 min Apple M 19 5 Low 6.80 7.0 6.8 6.1 6.9 6.2 6.7 Chocolate F 18 3 Low 5.2 6.2 7.5 5.9 5.9 5.4 4.8 Dates M 17 6 High 5.1 6.3 9.1 9.8 10.9 9.9 6.2 Ryvita F 19 6 Med 5.3 6.2 7.0 8.2 8.2 5.9 5.8 Mars bar F 18 4.5 Med 4.5 4.8 5.9 5.6 7.3 7.0 7.7 Jelly beans M 19 14 High 4.8 4.9 5.3 6.0 6.8 6.10 5.8 In the graph it is clear that all the test foods depicted a distinct pattern with respect to their GI category. In the figure above, the Dates which are a categorized as high GI foods shows an increased serum glucose levels achieving peak at around 45 minutes after fasting. In comparison, Ryvita and Mars Bar, medium GI foods, falls in the middle percentile with a gradual peak at around 50 minutes after fasting. Apple and Chocolate, low GI foods falls in the lowest percentile in the graph. However, jelly beans increase the serum glucose gradually until a peak is achievd at 60th minute. Discussion José et al. (2006) in their article notes that the effect of any particular test food on the Glycemic Index is entirely dependent on both its quality and quantity. Considering that Gycemic Load assesses the overall effect on the amount of food consumed, the disparity for instance between jelly beans and dates which are both high GI foods, may have been influenced by the amount consumed. The higher the GI of any types of food, the greater the elevation of blood glucose level. Subsequently, food composition and its condition -processed or not- influences its effect on Glycemic index. In comparison to documented GI values, Dates have a value of 103±21, Ryvita has 69±110, Mars Bar has 62±8, and Jelly Beans has 80±8 (Foster-Powell & Miller 1995). Conclusion With respect to this experimental study, there needs to be a more specialized research aiming at determining whether the age of the subjects and their gender any effects on changing the levels of serum glucose. Furthermore, the application of GI values in determining the effects of food on blood glucose levels is supported although other aspects such as status of the food for instance processing need to be established. References Brand-Miller J, Barclay AW, Irwin T 2001, ‘A new food labeling program for the glycemic index’, Proc Nutr Soc Aust, vol. 25, p. 21 David JA J, Cyril WC K, Livia SA A, Silvia F, Maryam H, Augustine M, Alexandra L J, and Mette A 2002, ‘Glycemic index: overview of implications in health and disease’, Am J Clin Nutr, vol. 76, pp. 266-273. Foster-Powell K, Miller J 1995, ‘International tables of glycemic index’, Am J Clin Nutr; vol. 62, no. pp. 871S–900S Kaye, FPl, Susanna, HA, and Janette, CB 2002, ‘International table of glycemic index and glycemic load values’, Am J Clin Nutr, vol 76, pp. 5–56. Read More