Frequently Asked Questions
- How is type 1 diabetes different from type 2 diabetes?
- Does diabetes cause symptoms?
- What if my sugar is above normal, but not high enough to diagnose diabetes?
- How can type 2 diabetes be prevented?
- Can my diabetes be treated without insulin injections?
- Do I have to avoid eating sugar?
- Why is my sugar so high in the morning, when I do not eat during the night?
- How low should I go — is tight blood-sugar control worth the effort?
Insulin is the hormone that helps to deliver sugar out of the bloodstream and into the muscles and other working tissues. There, it can be used for energy.
In type 1 diabetes mellitus, the body makes less insulin than is normal.
In type 2 diabetes mellitus, the body needs more insulin than is normal.
In both type 1 and type 2 diabetes, the body does not have enough insulin to meet its needs. As a result, type 1 and type 2 diabetes both result in high blood sugar levels. They share many of the same symptoms. They can cause many of the same health problems.
Type 1 and type 2 diabetes have very different causes. Their treatments also are different.
Type 1 diabetes results when the pancreas (your insulin factory) fails. Most often this is caused by the body's own immune system attacking the pancreas. Type 1 diabetes usually starts when you are a child or a young adult. The main treatment is to supply insulin to the body. People with type 1 diabetes can't survive without insulin injections. Treatment also includes diet and exercise, however.
Type 2 diabetes results when the body's tissues fail to respond to normal levels of insulin. Doctors call this change insulin resistance. Insulin resistance usually develops gradually with age. It is much more likely to develop in a person who is overweight or obese or has a family tendency toward diabetes.
Most type 2 diabetes shows up after age 40. But children, teenagers and younger adults also may develop type 2 diabetes. This is more likely if they are overweight.
Treatments are used to lower insulin resistance. One way to lower insulin resistance is to lose weight. Another way is to help cells in the body to respond more normally to insulin. Insulin resistance can be improved by a reduced-calorie diet, by exercise and also by a variety of medicines. Most people with type 2 diabetes can be treated for at least a portion of their adult years with pills. About 1 out of 3 people with type 2 diabetes require injections of insulin to help control the disease and its symptoms.
Diabetes does cause symptoms. Type 2 diabetes symptoms are sometimes mild, however. Some people have diabetes for months or even years without realizing that they are ill. Most people with diabetes do have symptoms. They feel much better when they receive treatment.
Diabetes is most likely to cause symptoms when it is not diagnosed or not adequately treated. The most common symptoms are:
- Frequent urination
- Blurred vision
- Unusually strong appetite
- Weight loss
- Recurring problems with yeast infections or fungal infections
For more information about type 2 diabetes symptoms and why they symptoms occur, visit our "Learn The Basics" diabetes symptoms section.
Diabetes also strongly increases your risk of dangerous health problems such as heart attack and stroke. Visit our "Keep On Track" section to learn the warning signs to report to your doctor.
The scientific group that most closely studies diabetes diagnosis around the world is the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. This expert sets guidelines for what blood-sugar levels are considered normal, and what levels diagnose diabetes or show an "in-between" state called pre-diabetes.
Specific tests of blood sugar are used to diagnose diabetes. A normal blood sugar (glucose) is below 100 milligrams per deciliter (mg/dl) if it is measured after an eight-hour fast. A "fast" means nothing to eat or drink except water. Normal blood sugar is less than 140 mg/dl if it is measured without a fast. Another way to look at blood sugar is to measure the percentage of blood cells that have a form called hemoglobin A1C. A normal A1C is 5.6% or lower.
Blood sugar test results that are well above normal — more than 125 if you have been fasting, or above 200 if you have been eating — indicate diabetes. Similarly, an A1C test with a result that is 6.5% or higher identifies diabetes. So what does it mean if your test results land somewhere in between "normal" and diabetes?
This middle range includes:
- Fasting glucose, 101 to 125
- Glucose after eating, 141 to 199
- A1C, 5.7% to 6.4%
In this middle range, you have a condition called pre-diabetes. Some doctors separate the condition into either impaired glucose tolerance (if you ate before your test) or impaired fasting glucose (if you did not eat before the test).
Mild glucose elevation means you are much more likely than average to develop diabetes. This is the reason doctors say that people with a test result in this range have pre-diabetes. As many as 1 out of 10 people with impaired glucose tolerance will develop diabetes within one year.
People with mild sugar elevations have an increased risk of heart attack and stroke. If your blood sugar is even a little higher than normal, your body may be developing insulin resistance. A person with insulin resistance often has other factors that increase the risk of heart and artery disease. When they occur together, these risks are known as the metabolic syndrome. The syndrome is common among people who have slightly high glucose, as well as those with full-blown diabetes.
If you have pre-diabetes, you should pay special attention to health habits that will reduce your risks of heart attack and stroke. Stay in close contact with your doctor. Get tested for diabetes often.
Thankfully, there are good strategies to prevent diabetes if you have pre-diabetes. The Diabetes Prevention Program showed how well these strategies can work. This was a three-year study of more than 3,200 people with impaired glucose tolerance (pre-diabetes). People in the study adopted careful — but reasonable — diet and exercise habits. They lost an average of 5% to 7% of their body weight. This change reduced their chance of developing diabetes during the years they were studied by nearly 60%.
The medicine metformin is also helpful. This drug makes the body more sensitive to insulin's effects.
Type 2 diabetes can be prevented in some high-risk people. People who have had slightly high blood sugar (above 100 milligrams per deciliter) are at very high risk of developing diabetes. These people have "pre-diabetes." A diagnosis of pre-diabetes means that you have a 1 in 10 chance of having full-blown diabetes within the next year.
A large study known as the Diabetes Prevention Program gave us encouraging news. This study looked for ways to reduce the risk of diabetes in people with pre-diabetes. People in the study made aggressive efforts to improve diet and exercise. This reduced their risk of developing diabetes within three years by nearly 60%.
On average, the people who were studied exercised about 30 minutes per day. They also reduced their calorie intake. As a result, they lost an average of 5% to 7% of their body weight.
The study also found that a medicine used to treat diabetes is useful for preventing it. Metformin reduced the risk of getting diabetes by 31%.
Why might it be helpful to treat pre-diabetes, instead of waiting to start medicine when diabetes is full-blown? Some experts think your heart disease risk increases sharply when you move from pre-diabetes to diabetes. If those experts are correct, then treatment for pre-diabetes is a sensible way to lower your heart disease risk. Using medicine to treat pre-diabetes is somewhat controversial.
This study should encourage people to exercise regularly and to eat a reduced-calorie diet. These efforts are most important for people who have pre-diabetes or other factors that increase their risk of type 2 diabetes. The risks include obesity or a family history of diabetes.
If you have type 2 diabetes, you can use many different ways to lower your blood sugar.
Exercise and a reduced-calorie diet both lower blood sugar. Together, they are the first-choice treatment for type 2 diabetes. A wide variety of pills can be used when exercise and diet changes do not lower blood sugar enough. Insulin is another reliable and safe treatment.
Here are the times that insulin may be the most practical medicine for type 2 diabetes:
- When the sugar is very high (with most readings over 250 milligrams per deciliter), you might need to start out with insulin injections. Later, you may be able to change to oral medicine (pills). Pills sometimes don't work well when the sugar level is very high. Insulin usually can be stopped in favor of pills after the sugar is brought to a more manageable level.
- Insulin is among the safest treatments for you if you are elderly or have heart failure or kidney disease.
- The dose of insulin can be raised as high as needed. If you have high blood sugar even though you take maximum doses of other drugs, insulin can keep your diabetes under control.
- Insulin is one of the least expensive medicines available for treating diabetes. It is one sensible choice if cost is an issue.
About 1 out of 3 people with type 2 diabetes require long-term insulin.
Diets that are low in total carbohydrates are not recommended for people with diabetes. However, it is best for you to limit the amount of refined carbohydrates that you eat. This includes sugar and processed grains such as white rice, white flour and pasta. Refined carbohydrates enter the bloodstream quickly. This can increase your sugar average. A regular habit of sugary foods also can lead to insulin resistance in your body over time.
You might imagine that sugar in your diet is what most directly builds up your blood-glucose level. After a sugary snack, this may be true. However, your digestion of well-balanced meals is not so simple. Your digestive tract and liver can take almost any form of nutrition and convert it into glucose. This includes fats, proteins and starches as well as sugar.
You should focus on your total calorie intake as well as the types of food you eat. All type 2 diabetics should eat a low-calorie diet. This clearly has been shown to lower blood glucose levels and reduce the risk of heart disease.
Some diabetics choose to use "non-nutritive sweeteners" (such as aspartame or saccharine) instead of sugar (sucrose). They provide more sweetness for fewer calories. As you think about how to cut calories, remember that the major calorie source of calories in a dessert may be fat, not sugar.
Some people with diabetes find it helpful to use sweeteners such as sorbitol, mannitol or xylitol instead of sugar. They tend to raise blood glucose less suddenly than regular sugar. These "sugar alcohols" frequently cause diarrhea. Like other sugars, they contain calories.
It may surprise you to know that sugar continues to enter your bloodstream throughout the night. No, you are not sleepwalking to your kitchen for secret snacks. Actually, your body has stored up sugar inside your liver during the day. When you stop eating, your liver lets this sugar flow into your bloodstream. Your liver also can make sugar out of the raw ingredients it has collected from other foods (such as fats).
Your body is less able to move glucose from the blood to the cells at night. This also can push up blood sugar. Hormones such as cortisol build up as a normal part of your nightly sleep cycle. These hormones interfere with the work of insulin. Insulin becomes less efficient at moving glucose into the cells.
Overnight, your muscles and other tissues also use less sugar. That's because you are less active. The extra sugar stays in the blood.
Altogether, these factors lead to high sugar levels in the morning for diabetics.
Pushing your blood sugar below 150 to 200 milligrams per deciliter (mg/dl) may eliminate most or all noticeable diabetes symptoms. But experts strongly recommend that you continue lowering your sugar, to nearly normal levels.
Tight blood-sugar control requires treatment with more than one medicine in most people who have had diabetes for five to 10 years. You have to pay close attention to your sugar levels, with frequent at-home monitoring. So, is this effort worth the trouble?
Yes, it is worthwhile, in almost every case.
As you get your sugars closer to normal, you will reduce your risk of health problems caused by diabetes. This was shown in the United Kingdom Prospective Diabetes Study. It was the largest study of type 2 diabetes patients in history. Results of this study allow us to predict how much benefit you will see from tight control.
Let's say you are able to lower your hemoglobin A1C (one measure of sugar control) from 9% to 8%, or from 8% to 7%. (Normal is usually about 6.2%.) For each drop of 1 percentage point, you can expect the following results:
- 35% reduced risk of eye damage (retinopathy) in the next 10 years
- 35% reduced risk of kidney damage in the next 10 years
- 18% reduced risk of heart attack during the next 10 years
- 7% reduced chance of dying within 10 years
- Reduced nerve damage
Tight control is safe for most people with type 2 diabetes. Tight control can increase the chance that you will have occasional hypoglycemic spells (low blood sugar). If you are elderly or have had a heart attack or stroke, this chance can make tight control a danger for you. If you have been unable to prevent episodes of hypoglycemia, then tight blood-sugar control is not your best plan. Keep this risk in mind when you discuss your sugar goals with your doctor.
The greatest benefit of tight control is in its prevention of long-term health problems. For this reason, people who are very elderly or who have a short life expectancy for other reasons may not benefit as much from tight control.
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