Low glycemic index foods work best for diabetics

By Imelda Angeles-Agdeppa, PhD
Food and Nutrition Research Institute

Diabetes is a disease that affects the way the body uses food.  It raises sugar levels in the blood.

During normal digestion, foods are converted into a form of sugar called glucose. The blood transports glucose to cells of the body with the help of insulin, a hormone manufactured by the pancreas.

The pancreas is a small organ near the stomach.  Glucose is then changed into usable energy for use by the cells.  The process of turning foods to energy is very important because the body always needs energy for any action, from thinking to running.

In diabetics, food is changed into glucose readily.  But there is a problem with insulin.  It may either be absent or insufficient.  Cells cannot use the glucose in the bloodstream to make energy.  The glucose accumulates in the blood leading to high sugar levels, a characteristic of untreated diabetes.

The signs and symptoms of diabetes are frequent urination, excessive thirst, extreme hunger, sudden weight loss, weakness and fatigue, recurring or hard to heal skin or gum infection, drowsiness, tingling or numbness in hands or feet, itching of skin and genitals, sudden vision changes, and blurred vision.

A diabetic may deliver a baby that weighs more than 4 kilograms.

For diabetics, food planning is very important.  Knowing what foods to avoid will help control the levels of blood sugar. 

The glycemic index of foods is a useful guide on what foods to eat.  GI is a classification of foods based on blood glucose response relative to a starchy food or glucose standard.  GI is influenced by factors such as starch structure, sugar, dietary fiber, presence of fat, protein, and degree of food processing.

Foods can be classified according to GI. The foods enumerated here use glucose as standard, where glucose has a value of 100.  Foods with high GI are cornflakes, rice cakes, watermelons, white rice, baked potatoes, and whole wheat breads.

Foods with moderate GI are ice cream, mango, oatmeal, and pineapple while those with low GI are apple, fettuccine and other pasta, oats, lentil, barley, soybean and other beans, and yogurt.

Low GI foods can decrease demand for insulin and improve insulin sensitivity.  These foods are digested and absorbed slowly resulting to a gradual rise in blood glucose and improved glycemic and weight control.  These foods when taken at supper can maintain blood glucose levels through the night.

It should be noted that GI should not be the only criterion used in planning the types of foods for diabetics.  Other important dietary considerations are the total amount of carbohydrate, amount and type of fat, and fiber and salt content of foods.

Understanding GI to ward off health inconveniences

Recent studies on large numbers of people with diabetes show that those who keep their blood sugar under tight control best avoid the complications of diabetes like heart disease, blindness, kidney failure, and lower extremity amputations.

Experts agree that what works well for people with diabetes—and everyone—are regular exercise, little saturated and trans-fatty acids, and high-fiber diet.  Carbohydrates break quickly during digestion and can raise blood sugar to dangerous levels.

 When diabetics make use of GI to prepare healthy meals, it keeps their blood sugar levels and weight under control.   Many carbohydrate-rich foods have high GIs, and certainly they are not good in any substantial quantity for people with diabetes.

Other carbohydrates like complex carbohydrates and dietary fiber break down more slowly, releasing glucose gradually into the blood streams and are said to have lower GIs which are good for diabetic patients.

Studies on GIs by experts showed that many of the starchy foods produce the highest glycemic response.  These are white bread, some breakfast cereals, e.g. cornflakes, and baked cheesy potatoes.

Low glycemic foods include beans, barley, pasta, oat, apple, orange, peach, peanut, strawberry, sweet corn, and carrot.  Vinegar and lemon juice help reduce glycemic load, the amount of carbohydrate in a serving of a particular food.

Many foods have few available carbohydrates in a standard serving.  These are called “free foods” because they are essentially free of any impact on blood sugar. These foods contain less than five grams of available carbohydrate in a 100-gram portion.  The rest of the portion is protein, fat, fiber, ash, and water. 

Examples of free foods are: (1) vegetables—asparagus, beans, cabbage, broccoli, cucumber, eggplant, lettuce, okra, mushroom, tomato, radish, spinach, turnip and pepper; (2) fruits—avocado, raspberry, strawberry; (3) eggs and dairy—cheese, milk, eggs, yogurt plain, and; (4) beverages—coffee, diet soda, tea, and water.

The GI should, however, not be the only criterion when selecting what to eat.  The total amount of carbohydrate, amount and type of fat, and the fiber and salt content are also important.  Factors such as variety of foods, cooking methods, and processing may also affect a food's GI.

[For more information on this topic, parties may write or call The Director, Food and Nutrition Research Institute, Department of Science and Technology, Gen. Santos Avenue, Bicutan, Taguig, Metro Manila, Tel/Fax: 8372934, 8373164; E-mail: cvcb@fnri.dost.gov.ph; FNRI-DOST website: http//www.fnri@dost.gov.ph]