Diabetes mellitus refers to a group of diseases that affect how your
body uses blood glucose, commonly called blood sugar. Glucose is vital
to your health because it's an important source of energy for the cells
that make up your muscles and tissues. It's also your brain's main
source of fuel.If you have diabetes, no matter what type, it means you have too much
glucose in your blood, although the reasons may differ. Too much glucose
can lead to serious health problems.Chronic diabetes conditions include type 1 diabetes and type 2 diabetes.
Potentially reversible diabetes conditions include prediabetes — when
your blood sugar levels are higher than normal, but not high enough to
be classified as diabetes — and gestational diabetes, which occurs
during pregnancy but may resolve after the baby is delivered.
Diabetes symptoms vary depending on how much your blood sugar is
elevated. Some people, especially those with pre-diabetes or type 2
diabetes, may not experience symptoms initially. In type 1 diabetes,
symptoms tend to come on quickly and be more severe. Some of the signs
and symptoms of type 1 and type 2 diabetes include:
- Increased thirst
- Frequent urination
- Extreme hunger
- Unexplained weight loss
- Presence of ketones in the urine
- Fatigue
- Blurred vision
- Slow-healing sores
- High blood pressure
- Frequent infections, such as gums or skin infections and vaginal or bladder infections
Although type 1 diabetes can develop at any age, it typically appears
during childhood or adolescence. Type 2 diabetes, the more common type,
can develop at any age and is often preventable. To understand diabetes, first you must understand how glucose is normally processed in the body.
How insulin works
Insulin is a hormone that comes from the pancreas, a gland situated behind and below the stomach.
- The pancreas secretes insulin into the bloodstream.
- The insulin circulates, enabling sugar to enter your cells.
- Insulin lowers the amount of sugar in your bloodstream.
- As your blood sugar level drops, so does the secretion of insulin from your pancreas.
The role of glucose
Glucose — a sugar — is a main source of energy for the cells that make up muscles and other tissues.
- Glucose comes from two major sources: food and your liver.
- Sugar is absorbed into the bloodstream, where it enters cells with the help of insulin.
- Your liver stores and makes glucose.
- When your insulin levels are low, such as when you haven't eaten in a
while, the liver metabolizes stored glycogen into glucose to keep your
glucose level within a normal range.
Causes of type 1 diabetes
In type 1 diabetes, your immune system — which normally fights harmful
bacteria or viruses — attacks and destroys your insulin-producing cells
in the pancreas. This leaves you with little or no insulin. Instead of
being transported into your cells, sugar builds up in your bloodstream.
Type 1 is thought to be caused by a combination of genetic
susceptibility and environmental factors, though exactly what many of
those factors are is still unclear.
Causes of pre-diabetes and type 2 diabetes
In pre-diabetes — which can lead to type 2 diabetes — and in type 2
diabetes, your cells become resistant to the action of insulin, and your
pancreas is unable to make enough insulin to overcome this resistance.
Instead of moving into your cells where it's needed for energy, sugar
builds up in your bloodstream. Exactly why this happens is uncertain,
although as in type 1 diabetes, it's believed that genetic and
environmental factors play a role in the development of type 2. Being
overweight is strongly linked to the development of type 2 diabetes, but
not everyone with type 2 is overweight.
Causes of gestational diabetes
During pregnancy, the placenta produces hormones to sustain your
pregnancy. These hormones make your cells more resistant to insulin. As
your placenta grows larger in the second and third trimesters, it
secretes more of these hormones — making it even harder for insulin to
do its job.
Normally, your pancreas responds by producing enough extra insulin to
overcome this resistance. But sometimes your pancreas can't keep up.
When this happens, too little glucose gets into your cells and too much
stays in your blood. This is gestational diabetes.
Risk factors for type 1 diabetes
Although the exact cause of type 1 diabetes is unknown, genetic factors
likely play a role. Your risk of developing type 1 diabetes increases if
you have a parent or sibling who has type 1 diabetes. Environmental
factors, such as exposure to a viral illness, also likely play some role
in type 1 diabetes. Other factors that may increase your risk include:
- The presence of damaging immune system cells that make autoantibodies.
Sometimes family members of people with type 1 diabetes are tested for
the presence of diabetes autoantibodies. If you have these
autoantibodies, you have an increased risk of developing type 1
diabetes. But, not everyone who has these autoantibodies develops type
1.
- Dietary factors. A number of dietary factors have
been linked to an increased risk of type 1 diabetes, such as low vitamin
D consumption; early exposure to cow's milk or cow's milk formula; or
exposure to cereals before 4 months of age. However, none of these
factors has been shown to cause type 1 diabetes.
- Race. Type 1 diabetes is more common in whites than in other races.
- Geography. Certain countries, such as Finland and Sweden, have higher rates of type 1 diabetes.
Risk factors for prediabetes and type 2 diabetes
Researchers don't fully understand why some people develop prediabetes
and type 2 diabetes and others don't. It's clear that certain factors
increase the risk, however, including:
- Weight. The more fatty tissue you have, the more resistant your cells become to insulin.
- Inactivity. The less active you are, the greater
your risk. Physical activity helps you control your weight, uses up
glucose as energy and makes your cells more sensitive to insulin.
Exercising less than three times a week may increase your risk of type 2
diabetes.
- Family history. Your risk increases if a parent or sibling has type 2 diabetes.
- Race. Although it's unclear why, people of certain
races — including blacks, Hispanics, American Indians and Asians — are
at higher risk.
- Age. Your risk increases as you get older. This may
be because you tend to exercise less, lose muscle mass and gain weight
as you age. But type 2 diabetes is also increasing dramatically among
children, adolescents and younger adults.
- Gestational diabetes. If you developed gestational
diabetes when you were pregnant, your risk of developing prediabetes and
type 2 diabetes later increases. If you gave birth to a baby weighing
more than 9 pounds (4 kilograms), you're also at risk of type 2
diabetes.
- Polycystic ovary syndrome. For women, having
polycystic ovary syndrome — a common condition characterized by
irregular menstrual periods, excess hair growth and obesity — increases
the risk of diabetes.
- High blood pressure. Having blood pressure over 140/90mm Hg is linked to an increased risk of type 2 diabetes.
- Abnormal cholesterol levels. If you have low levels
of high-density lipoprotein (HDL), or "good," cholesterol, your risk of
type 2 diabetes is higher. Low levels of HDL are defined as below 35
mg/dL.
- High levels of triglycerides. Triglycerides are a fat carried in the blood. If your triglyceride levels are above 250 mg/dL, your risk of diabetes increases.
Risk factors for gestational diabetes
Any pregnant woman can develop gestational diabetes, but some women are
at greater risk than are others. Risk factors for gestational diabetes
include:
- Age. Women older than age 25 are at increased risk.
- Family or personal history. Your risk increases if
you have prediabetes — a precursor to type 2 diabetes — or if a close
family member, such as a parent or sibling, has type 2 diabetes. You're
also at greater risk if you had gestational diabetes during a previous
pregnancy, if you delivered a very large baby or if you had an
unexplained stillbirth.
- Weight. Being overweight before pregnancy increases your risk.
- Race. For reasons that aren't clear, women who are
black, Hispanic, American Indian or Asian are more likely to develop
gestational diabetes.
Depending on what type of diabetes you have, blood sugar monitoring,
insulin and oral medications may play a role in your treatment. But no
matter what type of diabetes you have, eating a healthy diet,
maintaining a healthy weight and monitoring your blood sugar levels are
key to managing your diabetes.
Treatments for all types of diabetes
An important part of managing all types of diabetes is maintaining a healthy weight through a healthy diet and exercise plan:
-
Healthy eating. Contrary to popular
perception, there's no diabetes diet. You'll need to center your diet on
more fruits, vegetables and whole grains — foods that are high in
nutrition and fiber and low in fat and calories — and cut down on animal
products, refined carbohydrates and sweets. In fact, it's the best
eating plan for the entire family. Sugary foods are OK once in a while,
as long as they're included in your meal plan.
Yet understanding what and how much to eat can be a challenge. A
registered dietitian can help you create a meal plan that fits your
health goals, food preferences and lifestyle. This may include
carbohydrate counting, especially if you have type 1 diabetes.
- Physical activity. Everyone needs
regular aerobic exercise, and people who have diabetes are no exception.
Exercise lowers your blood sugar level by transporting sugar to your
cells, where it's used for energy. Exercise also increases your
sensitivity to insulin, which means your body needs less insulin to
transport sugar to your cells. Get your doctor's OK to exercise. Then
choose activities you enjoy, such as walking, swimming or biking. What's
most important is making physical activity part of your daily routine.
Aim for at least 30 minutes or more of aerobic exercise most days of the
week. If you haven't been active for a while, start slowly and build up
gradually.
Treatments for type 1 and type 2 diabetes
Treatment for type 1 diabetes involves insulin injections or the use of
an insulin pump, frequent blood sugar checks and carbohydrate counting.
Treatment of type 2 diabetes primarily involves monitoring of your blood
sugar, along with diabetes medications, insulin or both.
-
Monitoring your blood sugar. Depending on your
treatment plan, you may check and record your blood sugar level several
times a week to three or more times a day. Careful monitoring is the
only way to make sure that your blood sugar level remains within your
target range. People who receive insulin therapy may also choose to
monitor their blood sugar levels with a continuous glucose monitor.
Although this technology doesn't yet replace the glucose meter, it can
provide important information about trends in blood sugar levels.
-
Insulin. Most people with type 1 diabetes need insulin
therapy to survive. Some people with type 2 diabetes also need insulin
therapy. Often insulin is injected using a fine needle and syringe or an
insulin pen — a device that looks like an ink pen, except the cartridge
is filled with insulin. Many types of insulin are available, including rapid-acting insulin,
long-acting insulin and intermediate options. Depending on your needs,
your doctor may prescribe a mixture of insulin types to use throughout
the day and night.
- Oral or other medications. Sometimes other oral or
injected medications are prescribed as well. Some diabetes medications
stimulate your pancreas to produce and release more insulin. Others
inhibit the production and release of glucose from your liver, which
means you need less insulin to transport sugar into your cells. Still
others block the action of stomach or intestinal enzymes that break down
carbohydrates or make your tissues more sensitive to insulin.
- Transplantation. In some people who have type 1 diabetes, a pancreas transplant may be an option. Islet transplants are being studied as well. With
a successful pancreas transplant, you would no longer need insulin
therapy. But transplants aren't always successful — and these procedures
pose serious risks. You need a lifetime of immune-suppressing drugs to
prevent organ rejection. These drugs can have serious side effects,
including a high risk of infection, organ injury and cancer. Because the
side effects can be more dangerous than the diabetes, transplants are
usually reserved for people whose diabetes can't be controlled or those
who have serious complications.
- Bariatric surgery. Although it is not specifically
considered a treatment for type 2 diabetes, people with type 2 diabetes
who also have a body mass index higher than 35 may benefit from this
type of surgery. People who've undergone gastric bypass have seen
significant improvements in their blood sugar levels. However, this
procedure's long-term risks and benefits for type 2 diabetes aren't yet
known.
Treatment for gestational diabetes
Controlling your blood sugar level is essential to keeping your baby
healthy and avoiding complications during delivery. In addition to
maintaining a healthy diet and exercising, your treatment plan may
include monitoring your blood sugar and, in some cases, using insulin.
Your health care provider will also monitor your blood sugar level
during labor. If your blood sugar rises, your baby may release high
levels of insulin — which can lead to low blood sugar right after birth.
Treatment for pre-diabetes
If you have pre-diabetes, healthy lifestyle choices can help you bring
your blood sugar level back to normal or at least keep it from rising
toward the levels seen in type 2 diabetes. Maintaining a healthy weight
through exercise and healthy eating can help. Exercising at least 150
minutes a week and losing 5 to 10 percent of your body weight may
prevent or delay type 2 diabetes.
Sometimes medications — such as metformin (Glucophage, Glumetza, others)
— also are an option if you're at high risk of diabetes, including when
your prediabetes is worsening or if you have cardiovascular disease,
fatty liver disease or polycystic ovary syndrome.
In other cases, medications to control cholesterol — statins, in
particular — and high blood pressure medications are needed. Your doctor
might prescribe low-dose aspirin therapy to help prevent cardiovascular
disease if you're at high risk.
Type 1 diabetes can't be prevented. However, the same healthy lifestyle
choices that help treat pre-diabetes, type 2 diabetes and gestational
diabetes can help prevent them.
- Eat healthy foods. Choose foods low in fat and calories. Focus on fruits, vegetables and whole grains. Strive for variety to prevent boredom.
- Get more physical activity. Aim for 30 minutes of
moderate physical activity a day. Take a brisk daily walk. Ride your
bike. Swim laps. If you can't fit in a long workout, break it up into
smaller sessions spread throughout the day.
- Lose excess pounds. If you're overweight, losing
even 5 percent of your body weight — for example, 10 pounds (4.5
kilograms) if you weigh 200 pounds (90.7 kilograms) — can reduce the
risk of diabetes. To keep your weight in a healthy range, focus on
permanent changes to your eating and exercise habits. Motivate yourself
by remembering the benefits of losing weight, such as a healthier heart,
more energy and improved self-esteem.
Sometimes medication is an option as well. Oral diabetes drugs such as
metformin (Glucophage, Glumetza, others) may reduce the risk of type 2
diabetes — but healthy lifestyle choices remain essential.