What's the Difference Between Type 1 and Type 2 Diabetes?

Type 1 diabetes and type 2 diabetes are not the same disease. Learn about the differences between the two, and how each affects the body.

illustration of glucose and insulin in the bloodstream
The high levels of blood sugar in diabetes can result from a lack of insulin or the body's failure to respond to insulin.Gwen Shockey/Alamy

Type 1 and type 2 diabetes share the problem of high levels of blood sugar. The inability to control blood sugar causes the symptoms and the complications of both types of diabetes. But type 1 diabetes and type 2 diabetes are two different diseases in many ways. According to the latest (2014) estimates from the Centers for Disease Control and Prevention (CDC), 29.1 million people, or 9.3 percent of the U.S. population, have diabetes. Type 1 diabetes affects just 5 percent of those adults, with type 2 diabetes affecting up to 95 percent. Here’s what else you need to know to be health-savvy in the age of the diabetes epidemic.

What Causes Diabetes?

"Type 1 diabetes is an autoimmune disease — the body's immune system attacks the cells in the pancreas that make insulin," a hormone, says Andjela Drincic, MD, associate professor of internal medicine in the division of diabetes, endocrinology, and metabolism at the University of Nebraska Medical Center in Omaha. The exact cause is not known, but it's probably a combination of the genes a person is born with and something in the environment that triggers the genes to become active.

"The cause of type 2 diabetes is multifactorial," says Dr. Drincic. "People inherit genes that make them susceptible to type 2, but lifestyle factors, like obesity and inactivity, are also important. In type 2 diabetes, at least in the early stages, there is enough insulin, but the body becomes resistant to it." Risk factors for type 2 diabetes include a family history of the disease, a poor diet, a sedentary lifestyle, and obesity. African-Americans, Latin Americans, and certain Native American groups have a higher risk of type 2 diabetes than Caucasian Americans.

Can You Go from Type 2 Diabetes to Type 1 Diabetes?

Can You Go from Type 2 Diabetes to Type 1 Diabetes?

Juvenile or Adult-Onset: When Does Diabetes Start?

Usually, type 1 diabetes in diagnosed in childhood, while type 2 diabetes is typically diagnosed after age 40. But these aren't hard-and-fast rules. People are getting type 2 diabetes at increasingly younger ages and more adults are getting type 1 diabetes, says Shannon Knapp, RN, CDE, a diabetes educator at the Cleveland Clinic, highlighting the need for diabetes prevention at all ages.

What Does Diabetes Do to the Body?

People with type 1 diabetes do not produce insulin, and as a result sugar builds up in the blood instead of going into the cells, where it's needed for energy. In type 1 diabetes, high blood sugar causes symptoms like thirst, hunger, and fatigue and can cause devastating consequences, including damage to the nerves, blood vessels, and internal organs. The same scary complications of diabetes appear in type 2 as well. The difference is that people with type 2 diabetes still produce insulin; their bodies just become less sensitive to it over time, which is what causes the complications.

Are the Symptoms of Diabetes Different?

The first symptoms of type 1 diabetes appear when blood sugar gets too high. Symptoms include thirst, hunger, fatigue, frequent urination, weight loss, tingling or numbness in the feet, and blurred vision. Very high blood sugar can cause rapid breathing, dry skin, fruity breath, and nausea.

Meanwhile, the first symptoms of type 2 diabetes may not show up for many years — meaning the disease can ravage a person’s body without them realizing it. Early symptoms include frequent infections, fatigue, frequent urination, thirst, hunger, blurred vision, erectile dysfunction in men, and pain or numbness in the hands or feet. Drincic notes that "symptoms of type 2 diabetes don't start as suddenly as symptoms of type 1 diabetes."

Is Diagnosing Diabetes Types 1 and 2 Similar?

Blood tests used to diagnose type 1 and type 2 diabetes include fasting blood sugar, a hemoglobin A1C test, and a glucose tolerance test. The A1C test measures the average blood sugar level over the past few months. The glucose tolerance test measures blood sugar after a sugary drink is given.

"The blood sugar testing we do to diagnose and manage type 1 diabetes is very similar to the testing we do for type 2 diabetes," says Drincic. "We can do a blood test that looks for antibodies. That tells us if it is type 1 or 2." In type 1 diabetes, the immune system makes antibodies that act against the cells in the pancreas that make insulin, and these antibodies can be detected in a blood test. Your doctor may suspect type 2 diabetes based on your symptoms and risk factors, such as obesity and family history.

Is Diabetes Treatment Different, Too?

A good diabetes diet and regular exercise matters for people with type 1 and type 2 diabetes, Knapp explains. "The big difference is that everybody with type 1 diabetes needs to take insulin,” she says. “People with type 1 diabetes need to check their blood sugar level with a device called a glucometer about four times a day to know how much insulin to take."

Treatment for type 2 diabetes also starts with diet and exercise, and oral medication can also be used to increase the amount of insulin the pancreas makes, Knapp says. "Over time, if the pancreas stops making insulin, some people with type 2 will also need insulin." People with type 2 diabetes also need to check their blood sugar, from one to several times a day, depending on their state of health.

What Are the Complications of Diabetes?

"Whether it's type 1 or type 2," Drinsic says, "the big picture for diabetes is all about preventing complications," which are mostly related to nerve and blood vessel damage. For example, if you have either type of diabetes, you have twice the risk of heart attack or heart disease as compared with someone without the disease. Other complications include eye problems, kidney disease, foot infections, skin infections, stroke, high blood pressure, cognitive decline, and high cholesterol.

Can Diabetes Be Prevented or Cured?

"As of now there is no way to prevent or cure type 1 diabetes," Drincic notes. "There is lots of promising research, but it is still in the early stages." Some of the initiatives involve targeting the cells in the immune system that cause the autoimmune response. Other possibilities include the use of stem cells or pancreas transplants.

Another area of research is diet and its effects on both prevention and diabetes maintenance. A study published in March 2017 in the British Journal of Nutrition reported that following a diet high in plant nutrients and low in meat consumption lowers a person's risk of developing type 2 diabetes. The results indicated that certain compounds found in meat, rather than specific proteins, increased the risk of type 2 diabetes. Aside from eating healthy foods rich in plant nutrients, a large number of studies indicate that exercise is paramount not only for weight control, but also for maintaining a healthy, optimistic outlook.

"The best cure for type 2 diabetes is prevention, and research on that is very exciting," Drincic says. "Losing a moderate amount of weight and exercising regularly can reduce or delay type 2 diabetes significantly." For example, The Finnish Diabetes Prevention Study (DPS), a landmark study published in December 2003 in the journal Diabetes Care, followed 522 middle-aged, overweight subjects with risk factors for type 2 diabetes. A weight-loss diet and 30 minutes of daily exercise lowered their risk of developing type 2 diabetes by 58 percent compared with those who didn't follow the diet or exercise.