Understanding Diabetes, Part 1

By Nancy Sauer, Bakery Manager

This spring Open Harvest sponsored a cooking class called Delicious Diabetic Dining. The interest in the classes and the questions asked during them showed that there is a desire for information about what diabetes is and how one lives with it. The aim of this article is to provide a basic overview of what's known about diabetes.

Diabetes is the name of a group of diseases in which the body does not make or use insulin properly. Insulin is the hormone responsible for moving glucose, or sugar, out of the bloodstream and into the muscle and organ cells that need it. Glucose is the body's main energy source. One of the tasks of the digestive system is to break down the carbohydrates we eat and transform them into glucose. This is then absorbed by the blood and circulated through the body. If something happens to disrupt the body's insulin supply our cells go hungry while unused glucose builds up in the blood stream.

The two major varieties of diabetes are Type 1, in which the body is completely unable to manufacture insulin, and Type 2, in which the body either doesn't manufacture enough insulin or does not use insulin effectively. There is a third type of diabetes, gestational diabetes, which is a temporary condition affecting some women during pregnancy. Gestational diabetes usually goes away after the pregnancy, but women who have had it have a greater risk of developing Type 2 diabetes later in life.

Type 1 diabetes was once called juvenile-onset diabetes because it most often develops in children, teenagers and young adults. In this kind of diabetes, the islets, the special cells in the pancreas that manufacture insulin, have been completely destroyed leaving the person with no insulin at all. Persons with this type of diabetes must take insulin to regulate their blood glucose and so Type 1 is sometimes called insulin-dependent diabetes. About 5-10 percent of diabetics in the US have Type 1.

Type 2 diabetes was once called adult-onset diabetes because it was usually diagnosed in middle-aged or older adults. In this kind of diabetes the islets still make insulin but either they don't make enough or the body's cells don't use it efficiently. Some Type 2 diabetics need insulin to control their blood glucose but most can manage it effectively with medications that help the body to use its own insulin. For this reason Type 2 is sometimes referred to as non-insulin dependent diabetes. About 90-95 percent of diabetics in the US have Type 2.

At this point, both forms of diabetes are chronic diseases - they can be treated, but not cured. But the Diabetes Prevention Program sponsored by the National Institutes of Health has shown that it is possible to prevent or delay the development of Type 2 in persons who are at risk. By exercising 30 minutes a day five times a week and losing 5-10% of body weight (if one is overweight) you can reduce your risk of developing Type 2 diabetes. And since exercise and keeping a healthy weight also reduces your chances of heart disease and cancer, this is an all-around a good deal. See page 8 to learn about the new Diabetes Support Group.

Understanding Diabetes, Part 2

In this part will be a look at the causes of Type 1 and what research is being done on prevention or cures for it. Type 2 will be covered in part 3.

Type 1 diabetes is an autoimmune disease - one of the diseases caused by the body's immune system mistaking normal body tissue as an invader and attacking it. Systemic lupus erythematosus, rheumatoid arthritis, and celiac sprue are other examples of autoimmune diseases. In the case of Type 1, the insulin-producing beta-cells in the part of the pancreas known as islets are targeted as enemies and destroyed.

By studying the incidence of Type 1 in different populations, certain patterns have emerged. Type 1 is more common in Caucasians than in other ethnic groups, with the highest rates being found in the Scandinavian countries and Sardinia, Italy. This is evidence that part of the cause is genetic. However, studies done of identical twins have shown that genetics is not enough - when one twin has Type 1 diabetes, only about 30% of the cases does the other twin have it. This has led researchers to look for environmental triggers to the disease, and there is evidence that viruses, diet, or both may play a role. There is a great deal of research being done on the question of what exact combination of genes and environmental factors trigger Type 1.

Research on the prevention or cure of Type 1 is going on in many different areas, and the two issues are somewhat linked. Ultimately, a cure involves restoring the body's ability to make insulin. Transplants of whole pancreases or islet cells, or regrowing new islets from the patient's own cells would all in theory work, and all three areas are being investigated. But as long as the patient's immune system regarded the new beta cells as invaders this would only be a temporary treatment, and so research is also being done to understand why and how the immune system loses its ability to distinguish friend from foe. This information would in turn allow the possibility of stopping the immune system's attack on the beta cells before it went to completion, thus preventing Type 1 from developing at all.

Understanding Diabetes, Part 3

The causes of Type I diabetes are only partially known: It is clear that it is an autoimmune disease, but what causes the body to regard its pancreatic cells as an enemy is unknown. Type II diabetes is even more mysterious. It is characterized by the cells of the body becoming resistant to insulin, but how and why this occurs is unknown.

Some, but not all, Type II diabetics also have failure of the insulin-producing beta cells of their pancreas, and some but not all of them show the same immune responses as Type I diabetics. These observations, along with developing research on possible genetic and non-genetic causes of Type II, have led researchers to the possibility that Type II diabetes may not be a single disease but a family of diseases with different causes but similar symptoms.

The one thing that is clear is that medical research has a long way to go before we understand the causes of this disease.

Even with our current limited understanding, however, some things are clear. Obesity is apparently a risk factor, as is a lack of physical activity. This can be seen, somewhat tragically, in the recent upswing of Type II diabetes in children in the US. On the positive side, this points to ways that individuals can act to reduce their risk of developing Type II diabetes.

The Diabetes Prevention Program, a three year large-scale research study sponsored by the National Institute of Health, showed that people at risk of diabetes could delay or prevent onset by means of simple life-style changes. Participants in the study group who exercised for at least 30 minutes a day, five days a week and who received counseling on healthy eating choices reduced their risk of developing diabetes by 58% compared to the control group.

Based on this research the National Institutes of Health have issued some guidelines for Americans who want to reduce their risk of diabetes:

1. Eat a sensible diet that emphasizes fruits, vegetables, and whole grains.
2. Exercise at least 30 minutes a day five days a week. An elaborate exercise program isn't necessary, just walking will do fine.
3. If you are overweight, losing weight will help reduce your risk. You don't have to lose all your excess weight at once; losing just 5 to 10% of your body mass will lower your risk.

More complete information on the Diabetes Prevention Program and the National Institute of Health's recommendations can be found at: http://www.ndep.nih.gov/campaigns/ SmallSteps/SmallSteps_index.htm