A diabetic’s GI
(First of two parts)
We had an intimate dinner last weekend with Dr. Agnes Torrijos-Cruz, Dr. Arcy Cabalu, Winnie Sianda and other friends in our group we fondly call Familia Aqua Mocha. Since Agnes is the current vice president of Diabetes Philippines, a very active advocacy group composed of doctors and other healthcare professionals involved in the prevention of diabetes and its complications, our conversation inevitably shifted at one point to the alarming increase in the prevalence of diabetes in the Philippines.
The following morning, I caught Agnes speaking as the guest resource person in a popular TV program, still looking fresh despite our group’s late-night dinner the previous day. Listening to her very simple and clear explanations on what causes diabetes and how we unwittingly expose ourselves to a wanton lifestyle increasing our risk of developing diabetes and its complications, I was totally convinced that a continuous public education program is needed to equip everyone—lay people and doctors alike—with frequently overlooked information on what needs to be done to stem the tide of the diabetes epidemic in our country and worldwide.
We are said to be in the fast-food era, which is also fast leading us to the diabetic direction. If we don’t watch it, in 15 years the Philippines is projected to be among the top 10 countries in terms of increasing prevalence of diabetes.
Although we have modern drugs now that can bring down blood sugar levels effectively, diet and increased physical activity remain the mainstay of both prevention and treatment of diabetes. Drugs should not be considered an excuse for throwing caution to the wind when it comes to choosing the right food one should eat. Diabetic patients and those who are not yet diabetic but have a family history of diabetes should be well aware of the glycemic index or GI of the carbohydrate sources they eat.
In the ’80s, Dr. David Jenkins and his colleagues at the University of Toronto researched on foods that could be recommended for people with diabetes. Prof. Jennie Brand-Miller at the University of Sydney continued the research and developed the GI.
The GI is a measure of the effects of carbohydrates on blood sugar levels. Carbohydrates that break down rapidly after eating, releasing glucose rapidly into the bloodstream, have a high GI; while those that break down slowly, releasing glucose gradually into the bloodstream, have a low GI. Food items with a low GI are generally healthier for diabetics compared to those with a higher GI.
Foods with low GI have slower rates of digestion and absorption of the sugars and starches they contain. The carbohydrate or sugar load is relatively lower and less insulin is therefore required for digestion. This results in better blood sugar control. Even the lipids or cholesterol levels, particularly blood triglyceride levels, have been shown to be better controlled with more intake of low GI foods.
The current validated methods of measuring GI use glucose as the reference food, giving it a GI value of 100. The GI values of other foods can be interpreted as their relative percentages on an absolute scale with sugar as the reference.
Most fruits and vegetables (except potatoes, watermelon), grainy breads, pasta, legumes/pulses, basmati rice and milk have a relatively low GI of 55 or less. Croissant, brown rice, orange sweet potato and biscuits have a GI in the intermediate range of 55-69; and sweetened corn flakes, baked potato, white rice and white bread have relatively high GI of 70 or more. Candies, ice creams and some cakes may have GIs approximating sugar itself.
Although diabetics should only eat low GI food items under ordinary conditions, they may need a high-GI food for a more rapid rise in blood glucose levels for energy recovery after strenuous exercise and during times when they experience hypoglycemia or low blood sugar levels. Hypoglycemia may occur occasionally due to the antidiabetic drugs they take, particularly if they are on insulin.
Prevention of frequent and severe hypoglycemia is very important in preventing complications of diabetes. Hyperglycemia or elevated blood sugar is bad, but when it dips down too low, sudden and serious complications can also develop. It can even lead to sudden death due a fatal abnormality in the heartbeat, or some may even lead to coma when blood sugar levels drop to less than 50 milligrams per deciliter. So knowing when to eat high-GI foods is also important for diabetics when they feel signs of hypoglycemia like cold sweats, feeling of faintness, fast heart beat or palpitations.