Two of the most common forms of diabetes are Type 1 and Type 2. In Type 1 diabetes, the immune system destroys cells in the pancreas that produce insulin. In Type 2 diabetes, the body becomes resistant to insulin. This means the insulin the body produces cannot send its signal to the cells. Both types of diabetes can worsen if you eat a diet rich in refined carbohydrates.
The Role of Insulin in Metabolism
The main task of insulin is to signal to the cells when there are nutrients available in the bloodstream. To send this message to the cells, insulin binds to insulin receptors embedded in the cell membranes. This triggers transporters to embed into the cell membrane and nutrients are then absorbed into the cell through the transporters. The greatest spike in insulin occurs in response to high glucose levels, though amino acids, the building blocks of protein, and fat also contribute to elevated glucose levels.
Diabetes
When a patient has untreated diabetes, insulin is unable to communicate to the cells when food is present. As a result, glucose and other nutrients begin to accumulate in the bloodstream. Since insulin cannot communicate with the cells, the cells are essentially starving. This causes weight loss, and while some blood sugar is secreted in the urine, the excess blood sugar in the bloodstream can cause nerve damage. Daily insulin injections or insulin taken nasally together with dietary restrictions can help control Type 1 diabetes. Type 2 diabetes is normally controlled with dietary restrictions alone.
High Carbohydrate Diet
After a meal, the digestive tract converts fat into a protein-covered fat molecule, carbohydrates into glucose and protein into amino acids. As carbohydrates break down to glucose already in the digestive tract, they can give rise to a steep peek in blood sugar levels. This can be a dangerous condition in both Type 1 and Type 2 diabetes. In Type 1 diabetes, the daily doses of insulin are usually calculated relative to a diet that is low to moderate in carbohydrates. Filling up on carbohydrates can flood the bloodstream with more glucose than the injected insulin can handle. In Type 2 diabetes, the small amounts of insulin that can still bind to receptors cannot handle high-carbohydrate meals. So, in both cases, a high carbohydrate diet could cause dangerously high levels of glucose.
High-Glycemic Index Vs. Low-Glycemic Index Diets
Not all carbohydrates are equally bad for people with diabetes. Carbohydrate foods that break down fast, such as white bread, potato chips and sugar, have a high glycemic index, whereas carbohydrate foods that break down more slowly, such as brown rice, whole grain bread and pasta, vegetables and legumes, have a low glycemic index. As low-glycemic-index foods do not flood the bloodstream with glucose to the same extent as low-glycemic index carbohydrates, they are a safer choice of carbohydrates for people with diabetes.
References
- National Institute on Diabetes and Digestive and Kidney Diseases:Insulin Resistance and Pre-Diabetes
- American Diabetes Association: Diabetes Basics
- MayoClinic.com: Diabetes
- "Nutrition and Metabolism"; Low-carbohydrate diet in type 2 diabetes: stable improvement of bodyweight and glycemic control during 44 months follow-up Jörgen V Nielsen; May 2008 and Eva A Joensson;
- Harvard School of Public Health: Carbohydrates: Good Carbs Guide the Way
