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  • Kinship  Between  Glycemic Index and  Diabetes

    March 28, 2019


          

              Rupendra  Shakya –  The impact of carbohydrates on blood glucose levels has been recognized by doctors and the medical community for at least the past 2 decades. After a high-glycemic load meal, blood glucose levels increase more steeply, and the demand for insulin will rise greatly. In other words, a high carbohydrate meal puts stress on pancreatic function and increases the risk of developing Type 2 diabetes. Fundamentally, there is an inherent relationship between the glycemic index and diabetes.

    The glycemic index, or GI, is a food ranking system that gives a lower number to foods that result in lower and more gradual blood glucose increases, and a higher number to foods that raise blood glucose levels more drastically and more quickly. In between these numbers, is the medium GI. Foods such as most high fiber vegetables and oats have a low glycemic index, while white bread, certain fruits and potatoes have a high GI. The high glycemic index and diabetes have a detrimental relationship on health.

    In the treatment of diabetes, one must pay attention to both glycemic index and glycemic load. Due to the relationship between the GI and diabetes, there are foods that increase the probability of the onset of diabetes.                     .

    While a particular food has a ranking within the glycemic index, the total glycemic load will depend on the serving size, together with the amount of carbohydrate in that serving. For example, dried pulse that are boiled have a glycemic index of 29,  which goes up to a value of 55. If you consume just one cup of pulse, the carbohydrate per serving will be 18 grams. The total glycemic load per serving, however, is actually 5. In other words, the actual effect of eating a small portion of boiled pulse produces a lower glycemic load than one would think. Therefore, glycemic index and diabetes considerations should include both the quality of the food (glycemic index) and quantity of the carbohydrate contained in the food.

    The physiological effects of high glycemic index foods have been shown to rapidly increase blood glucose levels. When an individual consistently eats high GI foods, it results in rapid increases in blood sugar, prompting high insulin levels. Over the next few hours after a high glycemic load meal, insulin levels are high, resulting in a sharp drop in glucose levels. This rapid rise and fall of blood sugar is what puts the strain on the pancreas and can ultimately lead to diabetes. Consuming a low GI diet results in more gradual and tepid rises in blood sugar, and therefore puts less demand on the pancreas to release a large amount of insulin. Subsequently, in terms of the glycemic index and diabetes, eating a low GI diet reduces your risk of diabetes.

    Low glycemic index diets have been shown to improve overall blood sugar control in people with both Type 1 and Type 2 diabetes. The American Diabetes Association recommends that individuals with diabetes reduce their calorie intake, maintain a healthy weight, and count the carbohydrates they consume. A low GI diet, taking into account food portions that add up to total glycemic load, is a way to attain effective control of blood sugar, along with weight loss. Subsequently, a low glycemic index diet and diabetes have a healthy relationship.

    High glycemic index foods can raise blood glucose levels very quickly, as well as insulin levels. In contrast, low glycemic index foods do not significantly raise blood glucose levels and insulin levels after eating. Pure glucose is given a value of 100 while other foods are given an index number representing its relative effect on blood glucose levels. For example, sweet corn is assigned an index number of 55 which means sweet corn raises blood glucose levels 55 percent as much as pure glucose. In general, foods below 55 are considered low glycemic index foods, 55-70 represents mid-glycemic index foods and over 70 are considered high glycemic foods. In the past, it was widely believed that simple sugars dramatically increased blood glucose levels while starches such as potatoes and bread were digested slowly.

    The body regulates the levels of blood glucose to avoid the detrimental effects of a prolonged high, or low, blood sugar by releasing hormones like insulin and other chemicals. High blood glucose causes insulin production, which helps the glucose move out of the blood stream and into fat cells and muscles. Low blood glucose causes the release of other chemicals and hormones, which reduce the effectiveness of insulin and help bring blood glucose back to normal levels.

    Meals containing high glycemic foods can cause the blood glucose to rise twice as high, as a meal of low glycemic foods, containing the same number of calories and nutrients. The high glycemic meal causes a much higher insulin output, which would tend to increase the storage of glycogen and fat. Even though nutrient absorption slows after 2-4 hours, elevated levels of insulin remain, causing blood glucose to drop further–often resulting in hypoglycemia—very low blood glucose. Four to six hours after this meal, a second group of hormones is released, in amounts normally found only after many hours of fasting, as the body fights to restore nutrient levels in the blood.

    High glycemic meals raise blood glucose so high, extra insulin is produced, quickly sending sugars into the body cells, dramatically lowering blood glucose, causing the body to release hormones to increase hunger and appetite to restore blood glucose. In tests where drugs are given to prevent the uptake of glucose into cells, subjects showed increased appetite and overeating long after blood glucose returned to normal. Low blood sugar causes overeating even though it all began with a very high blood sugar.

    In conclusion, it does seem that high glycemic diets may increase appetite, food intake, fat deposition and overwork the cells that produce insulin. High glycemic foods may therefore increase the risk of obesity, type 2 diabetes and heart disease.

    (Assistant Professor and Medical Biochemist, Crimson College of Technology and Crimson Hospital Butwal , Nepal)