DO TRADITIONAL FOODS HELP TO DECREASE THE GLYCAEMIC INDEX? Selladurai Pirasath Demonstrator, Faculty of Medicine, University of Jaffna.

Supervisors: Prof: Vasanthy Arasaratnam, Vice-Chancellor, University of Jaffna. Dr.S.Balakumar, Senior Lecturer, Faculty of Medicine,

Glycaemic Index The Glycaemic Index is a numerical Index that ranks carbohydrates based on their rate of glycemic response Glycaemic Index uses a scale of 0 to 100 Standard foods-Glucose/white bread GI - WHO “The incremental area under the blood glucose response curve of 75g carbohydrate portion of a food Expressed as a percent of response to same amount of carbohydrate from a standard food taken by same subject”

Factors affecting the GI Degree of ripeness Physical form of the food Degree of processing Type of carbohydrates Chemical composition of starch Cooking method Type and amount of sugar Speed of eating Fibers Soluble fiber Insoluble fiber Fat and protein content Methods of food preparation Degree of starch gelatinization

Effects of fiber Insoluble fiber Soluble fiber (viscous) Little effect on digestibility of carbohydrate foods Very large amount-lower the glycemic index of foods Soluble fiber (viscous) Decreases rate of digestion -impedes access to digestive enzymes Decreases rate of absorption Sugars in fiber-rich foods tend to be absorbed into the bloodstream more slowly

Advantages of Low GI diets Diabetes mellitus Coronary heart disease (CHD) Cancer Attention deficit disorder Weight control

Objective Determination of the glycaemic index of traditional foods in Jaffna

Materials and methods

Foods selection White rice (‘Bg- 11-11’) Brown rice (‘At- 402’) Analysis of Glycaemic Index of traditional foods White rice (‘Bg- 11-11’) Brown rice (‘At- 402’) Parboiled rice (‘Mottaikarupan’) Pittu [ Rice flour : Wheat flour = 1:2] String hopper [ Rice flour : Wheat flour = 1:2] TUBERS potato (Solanum tubrosum) cassava (Manihot esculenta) LEGUMES green gram (Vigna radiata) chick pea (Cicer arietinum).

Food analysis

Subjects selection 22volunteers 11females and 11 males Mean body mass index – 21.9 (±2.75) kgm-2 Mean age – 24.62 (±1.43) years Mean height – 1.7 (±0.07) m Mean weight – 63.42 (±10.5 kg 22volunteers 11females and 11 males

Determination of the peak glycaemic response to the glucose 75g glucose dissolved in 300mL water. 22 volunteers. Blood glucose level measured half hourly for 2 hours. Glycaemic response for glucose were calculated at 30, 60, 90 and 120min. Blood glucose reached peak at 30min.

Determination of peak glycaemic response to different food items Each test food – 75 g digestible CHO food Pilot study - 3 Volunteers Elaborate study – 22 Volunteers Blood glucose level was measured half hourly for 2 hours. Glycaemic responses for each test foods were calculated at 30,60,90 & 120 min. Maximal glycaemic response obtained at 30 min.

Results & Discussion

Peak glycaemic response to the glucose Figure1: The mean glycemic response for glucose at 30, 60, 90& 120min

Pilot and elaborate studies to determine the glycaemic index of different varieties of rice Figure 2: The mean glycaemic response obtained in three volunteers for different varieties of rice at ( ) 30 and 60( ) min Figure 3: The mean glycemic response values obtained in 22 volunteers for different varieties of rice at 30min

Glycaemic index of different varieties of rice Table 1: Proximate compositions of different varieties of rice Constituents % White rice Brown rice Parboiled rice Moisture 62.41 70.28 65.54 Total protein 1.53 1.78 2.18 Soluble dietary fiber Trace 0.21 0.42 Insoluble dietary fiber 1.21 1.88 Total dietary fiber 2.09 2.30 Total digestible carbohydrate 26.22 22.19 23.10 Figure 4: The mean glycaemic index values obtained in 22 volunteers for different varieties of rice at 30min

Pilot and elaborate studies to determine the glycaemic index of Pittu & stringhopper Figure 5: The mean glycaemic response obtained in three volunteers for pittu & string hopper at ( ) 30 and 60( ) min Figure 6: The mean glycaemic response values obtained in 22 volunteers for pittu & string hopper at 30min

Glycaemic index of Pittu & string hopper Table 2: Proximate compositions of pittu & string hopper Constituents % Pittu String hopper Moisture 47.43 53.67 Total protein 4.40 3.67 Soluble dietary fiber 0.45 0.43 Insoluble dietary fiber 1.56 1.45 Total dietary fiber 2.01 1.88 Total digestible carbohydrate 45.03 37.50 Figure 7: The mean glycemic index Values obtained in 22 volunteers for pittu & string hopper

Pilot and elaborate studies to determine the glycaemic index of tubers Figure 8: The mean glycaemic response obtained in three volunteers for different varieties of tubers at ( ) 30 and 60( ) min Figure 9: The mean glycemic response values obtained in 22 volunteers for different varieties of tubers at 30min

Glycaemic index of different varieties of tubers Table 3: Proximate compositions of tubers Constituents % Cassava Potato Moisture 64.09 73.6 Total protein 0.45 2.99 Soluble dietary fiber 0.47 0.48 Insoluble dietary fiber 2.18 1.21 Total dietary fiber 2.65 1.69 Total digestible carbohydrate 32.25 20.17 Figure 10: The mean glycaemic index values obtained in 22 volunteers for different varieties of tubers at 30min

Pilot and elaborate studies to determine the glycaemic index of legumes Figure 11: The mean glycaemic response obtained in three volunteers for legumes at ( ) 30 ,60and 90( ) min Figure 12: The mean glycaemic response values obtained in 22 volunteers for legumesat 60min

Glycaemic index of Legumes Table 4: Proximate compositions of legumes Constituents % Green gram Chick pea Moisture 57.79 56.37 Total protein 7.59 6.01 Soluble dietary fiber 0.43 0.40 Insoluble dietary fiber 8.76 7.19 Total dietary fiber 9.19 Total digestible carbohydrate 25.43 29.62 Figure 13: The mean glycemic index values obtained in 22 volunteers for legumes

Statistical analysis Glycaemic response and glycaemic index values were analyzed by Randomized Complete Block Design using SAS analytical package.

Table 5: Comparision of Glycaemic response and Glycaemic index values of basic foods using P values Basic foods Glycaemic Response Glycaemic Index White rice P < 0.05 P < 0.05 P < 0.05 P < 0.05 P < 0.05 Brown rice P < 0.05 P < 0.05 Parboiled rice P < 0.05 P < 0.05 Pittu P < 0.05 P < 0.05 P < 0.05 P < 0.05 String hopper

Table 6: Comparision of Glycaemic response and Glycaemic index values of tubers and legumes using P values Fruit items Glycaemic Response Glycaemic Index Cassava P < 0.05 P < 0.05 P < 0.05 P < 0.05 P < 0.05 Potato Chick pea P > 0.05 P < 0.05 P > 0.05 P < 0.05 Green gram P > 0.05 P < 0.05 P > 0.05 P < 0.05

Conclusion Figure 14: The mean glycemic index values obtained in 22 volunteers for local foods

LOW GI DIETS INTERMEDIATE GI DIETS HIGH GI DIETS Pittu [ Rice flour : Wheat flour = 1:2] String hopper [ Rice flour : Wheat flour = 1:2] Chickpea Green gram INTERMEDIATE GI DIETS White rice (‘Bg- 11-11’) Brown rice (‘At- 402’) Parboiled rice (‘Mottaikarupan’) Potato HIGH GI DIETS Cassava

Get the “Message” from research; “CONSUMPTION OF SOLUBLE FIBER DIETS DECREASE THE GLYCAEMIC INDICES”

Diabetes mellitus is the greatest health challenge among adults PRIMORDIAL PREVENTION IS ESSENTIAL SINCE ADOLESCENT AGE Concept of GI Adolescent nutritional health care “Theme of Scientific Session”

Glycaemic index values [42] food items are available in Sri Lanka. International journal of food science and nutrition [in press] 2011; UK Journals Rice Science journal 2011; CHINA. Journal of Science 2009; AFRICA. Indian journal of medical science 2010;INDIA.

Free papers in Annual scientific sessions; Ceylon medical journal 2010; vol 55. Ceylon medical journal 2011[suppl]; vol 56. Free papers in Annual scientific sessions; 42nd Annual Scientific Session, Ceylon College of Physicians,2009. 44th Annual Scientific Session, Ceylon College of Physicians,2011.

124th Annual Scientific Session, Sri Lanka Medical Association,2011. 44th Annual Scientific Session, Ceylon College of Community Physicians,2011. Annual Scientific Session, University of Colombo,2009. Annual Scientific Session, Batticaloa Medical Association,2009. Annual Scientific Session, Jaffna Science Association,2008.

References Foster-Powell K, Holt SHA, Brand Miller JC. International table of glycaemic index and glycaemic load values. Am J Clin Nutr 2002;76:5-56. Wolver TMS, Jenkins, DJA, Jenkins AL, Josse RG. The Glycaemic index: Methodology and Clinical Implications. Am J Clin Nutr 1991;54:846-54. Mendosa, D. Glycemic Index. The glycemic index ranks foods on how they affect our blood glucose levels. 2007.Available at www.mendosa.com/gi.htm.

Acknowledgement Supervisors Committee of BMA Volunteers Sincere thanks to Supervisors Committee of BMA Volunteers Financial assistances

University of Jaffna - Thilliampalam Kanagasabai research fund IRQUE medical study programme, Research fund of Faculty of Medicine, University of Jaffna. George Steuart, Agencies (PVT) Ltd ,Diagnostic Vision, Mount Lavinia.

Thank you