Glycemic Index - Disease Prevention

Disease Prevention

Several lines of recent scientific evidence have shown that individuals who followed a low-GI diet over many years were at a significantly lower risk for developing both type 2 diabetes, coronary heart disease, and age-related macular degeneration than others. High blood glucose levels or repeated glycemic "spikes" following a meal may promote these diseases by increasing systemic glycative stress, other oxidative stress to the vasculature, and also by the direct increase in insulin levels. The glycative stress sets up a vicious cycle of systemic protein glycation, compromised protein editing capacity involving the ubiquitin proteolytic pathway and autophagic pathways, leading to enhanced accumulation of glycated and other obsolete proteins.

In the past, postprandial hyperglycemia has been considered a risk factor associated mainly with diabetes. However, more recent evidence shows that it also presents an increased risk for atherosclerosis in the non-diabetic population and that high GI diets and high blood-sugar levels more generally and are related to kidney disease as well.

Conversely, there are areas such as Peru and Asia, where people eat high-glycemic index foods such as potatoes and high-GI rices, but without a high level of obesity or diabetes. The high consumption of legumes in South America and fresh fruit and vegetables in Asia likely lowers the glycemic effect in these individuals. The mixing of high- and low-GI carbohydrates produces moderate GI values.

A study from the University of Sydney in Australia suggests that having a breakfast of white bread and sugar-rich cereals, over time, may make a person susceptible to diabetes, heart disease, and even cancer.

A study published in the American Journal of Clinical Nutrition found that age-related adult macular degeneration (AMD), which leads to blindness, is 42% higher among people with a high-GI diet, and concluded that eating a lower-GI diet would eliminate 20% of AMD cases.

The American Diabetes Association supports glycemic index but warns that the total amount of carbohydrate in the food is still the strongest and most important indicator, and that everyone should make their own custom method that works best for them.

The International Life Sciences Institute concluded in 2011 that because there are many different ways of lowering glycemic response, not all of which have the same effects on health, "It is becoming evident that modifying the glycaemic response of the diet should not be seen as a stand-alone strategy but rather as an element of an overall balanced diet and lifestyle."