Diabetes Mellitus (Type 1 and Type 2)

Diabetes (Type 1 and Type 2) Quick Overview

Learn the signs of diabetes, the types, and how to manage diabetes with a diabetic diet and lifestyle changes
Learn the signs of diabetes and how it can be managed with diet and lifestyle changes.
  • Diabetes is a condition characterized by the body's inability to regulate glucose (sugar) levels in blood.
  • In type 1 diabetes, the body does not produce enough insulin.
  • People with type 2 diabetes can produce insulin, but the body is not able to use the insulin effectively.
  • Symptoms of both type 1 and type 2 diabetes include
  • The cause of type 1 diabetes is an autoimmune disorder in which the immune system slowly destroys the insulin-producing beta cells in the pancreas. Combinations of genetic factors and unhealthy lifestyle choices cause type 2 diabetes.
  • The main diagnostic test for diabetes is measurement of the blood glucose level.
  • Changes in lifestyle and diet may be adequate to control type 2 diabetes in some people. Other people with type 2 diabetes require medications. Insulin is essential treatment for type 1 diabetes.
  • To date, only the drug teplizumab has proven effective to slow progression to type 1 diabetes in some early cases detected before clinical onset. No approach has yet proven effective to prevent type 1 diabetes. Prevention of type 2 diabetes can be accomplished in some cases by:
    • maintaining a healthy weight,
    • regular, moderate to vigorous exercise,
    • sustaining a healthy lifestyle, such as nicotine abstinence.
  • Prediabetes is a condition that can occur before development of type 2 diabetes.
  • Any type of diabetes mellitus over time can damage blood vessels and nerves. Damage to blood vessels can lead to heart disease, kidney disease, and vision problems including blindness. Nerve damage can result in diabetic neuropathy.

What Is Diabetes?

Diabetes mellitus (DM) is a set of related diseases in which the body cannot regulate the amount of sugar (specifically, glucose) in the blood.

The blood delivers glucose to provide the body with energy for all daily activities.

  • The liver converts the food a person eats into glucose (simple sugar) and stores this glucose as starch (called glycogen). The liver releases stored glucose into the bloodstream between meals.
  • In a healthy person, several hormones tightly regulate the blood glucose level, primarily insulin. Insulin is produced by the pancreas, a small organ located in the upper belly between the stomach and liver. The pancreas also releases other important enzymes directly into the gut to help digest food.
  • Insulin allows glucose to move out of the blood into cells throughout the body, where it is used for fuel.
  • People with diabetes mellitus either do not produce enough insulin (type 1 diabetes), cannot use insulin properly (type 2 diabetes), or both (various forms of diabetes).
  • In diabetic patients, glucose cannot move efficiently from the blood into cells, so blood glucose levels remain high. This not only starves all the cells, which need the glucose for fuel, but over time also harms certain organs and tissues exposed to high glucose levels.

What Are the Types of Diabetes?

Type 1 diabetes (T1D)

The body produces little or no insulin to regulate blood glucose level.

  • T1D affects about 10% of all people with diabetes in the United States.
  • T1D is typically diagnosed during childhood or adolescence. In the past T1D was called juvenile-onset diabetes or insulin-dependent diabetes mellitus.
  • Insulin deficiency can occur at any age due to destruction of the pancreas by alcohol, disease, or removal by surgery.
  • T1D results from progressive destruction by the immune system of the pancreatic beta cells, the only cell type that produces significant amounts of insulin.
  • People with T1D require daily insulin treatment to sustain life.

Type 2 diabetes (T2D)

Although the pancreas still secretes insulin in someone with T2D, the body’s tissues are partially or completely incapable of responding to insulin. This is often referred to as insulin resistance. The pancreas tries to overcome this resistance by secreting more and more insulin. People with insulin resistance develop T2D when they fail to secrete enough insulin to cope with their body's demands.

  • At least 90% of adult individuals with diabetes have T2D.
  • T2D is typically diagnosed during adulthood, usually after age 45 years. It was once called adult-onset diabetes mellitus, or non-insulin-dependent diabetes mellitus. These names are no longer used, because T2D can occur in young people, and some people with T2D require insulin therapy.
  • T2D is usually controlled with diet, weight loss, exercise, and/or oral medications. However, more than half of all people with T2D require insulin to control their blood sugar levels at some point during the course of their disease.

Gestational diabetes (GDM)

Gestational diabetes (GDM) is a form of diabetes that occurs during the second half of pregnancy.

  • Although gestational diabetes typically resolves after delivery of a baby, a woman who develops gestational diabetes is more likely than other women to develop T2D later in life.
  • Women with gestational diabetes are more likely to have large babies, complicated pregnancies, and complicated deliveries.

Metabolic syndrome

Metabolic syndrome (also referred to as syndrome X) is a set of abnormalities in which insulin resistance or T2D is almost always present along with hypertension (high blood pressure), high fat levels in the blood (increased serum lipids, predominant elevation of LDL cholesterol, decreased HDL cholesterol, and elevated triglycerides), central obesity, and abnormalities in blood clotting and inflammatory responses. A high rate of cardiovascular disease is associated with metabolic syndrome.


Prediabetes is a common condition related to diabetes. In people with prediabetes, the blood sugar level is higher than normal but not yet high enough to be considered diagnostic of diabetes mellitus.

  • Prediabetes increases a person's risk of developing T2D, heart disease, or stroke.
  • Prediabetes can typically be reversed (without insulin or medication) by sustained lifestyle changes, such as losing a modest amount of weight and increasing physical activity levels. Weight loss can prevent, or at least delay, the onset of T2D.
  • An international expert committee of the American Diabetes Association redefined the criteria for prediabetes, lowering the blood sugar level cut-off point for prediabetes in adults. Approximately 20% more adults are now believed to have this condition and may develop diabetes within 10 years unless they change to healthier lifestyles, such as exercising more and maintaining a healthy weight.

About 17 million Americans (6.2% of adults in North America) are believed to have diabetes mellitus. Some experts estimate that about one-third of adults with diabetes do not know they have diabetes mellitus.

  • About 1 million new cases of diabetes mellitus are diagnosed each year. Diabetes mellitus directly or indirectly causes at least 200,000 deaths each year.
  • The rates of people affected by T1D and T2D are increasing rapidly. These increases are due to many factors. The most significant reason for T2D is the increasing number of obese people due to sedentary lifestyles.

What Are the Causes of Diabetes?

Type 1 diabetes causes

T1D is an autoimmune disease. The body's immune system specifically destroys the cells in the pancreas that produce insulin.

  • A predisposition to develop T1D may run in families. However, genetic causes (i.e., a positive family history) are much more common for T2D.
  • Common and unavoidable viral infections are among the environmental factors which contribute to T1D by triggering autoimmunity.
  • T1D is most common among people of non-Hispanic, Northern European descent (especially Finland and Sardinia), followed by African Americans, and Hispanic Americans. It is relatively rare among Asian Americans.
  • T1D is slightly more common in men than in women.
  • T1D most often presents before age 21 but can occur at any age.

Type 2 diabetes causes

T2D is strongly linked to genetics, so T2D tends to run in families. Several genes have been linked to T2D, and many more are under study. Risk factors for developing T2D include:

  • High blood pressure
  • High triglyceride (fat) levels in the blood
  • Gestational diabetes or giving birth to a baby weighing more than 9 pounds
  • High-fat diet
  • High alcohol intake
  • Sedentary lifestyle
  • Obesity or being overweight
  • Ethnicity, particularly when a close relative had T2D or gestational diabetes. African Americans, Native Americans, Hispanic Americans, and Japanese Americans display greater risks of developing T2D than non-Hispanic white Americans.
  • Aging: Increasing age is a significant risk factor for T2D. Risk begins to rise significantly at about age 45 years, and rises considerably after age 65 years.

What Are Diabetes Symptoms and Signs?

Type 1 diabetes symptoms

Symptoms of type 1 diabetes are often dramatic and come on very suddenly.

  • T1D is usually recognized in childhood or early adolescence, often in association with an injury or illness (such as a virus or urinary tract infection).
  • The extra stress can cause diabetic ketoacidosis (DKA).
    • Symptoms of ketoacidosis include nausea and vomiting. Dehydration and often serious disturbances in blood levels of potassium and other factors follow.
    • Without treatment, ketoacidosis can lead to coma and death.

Type 2 diabetes symptoms

Symptoms of type 2 diabetes are often subtle and may be attributed to aging or obesity.

  • A person may have T2D for many years without knowing it.
  • People with T2D can develop the hyperglycemic hyperosmolar nonketotic (“HONK”) syndrome.
  • T2D can be precipitated by steroids and stress.
  • If not properly treated, T2D can lead to complications such as blindness, kidney failure, heart disease, and nerve damage.

Common symptoms of both type 1 and type 2 diabetes include:

  • Fatigue, or feeling constantly tired: With diabetes, the body’s metabolism is inefficient and sometimes unable to use glucose for fuel. The body switches over to metabolizing fat, partially or completely, as a fuel source. This process requires the body to use more energy. The end result is feeling fatigued or constantly tired.
  • Unexplained weight loss: People with diabetes mellitus are unable to metabolize food. They may lose weight even though they appear to eat appropriate or even excessive amounts of food. Losing sugar and water in the urine can lead to dehydration and unintentional weight loss.
  • Excessive thirst (polydipsia): A person with diabetes mellitus develops high blood sugar levels. When kidneys filter this blood, the high sugar content overwhelms the kidney's ability to control sugar filtering. The kidney spill excess sugar into the urine, resulting in large amounts of urine. The body tries to counteract this by sending a signal to the brain to dilute the blood, which translates into thirst. Thirst encourages more drinking (i.e., water consumption) to dilute the high blood sugar down to normal levels and to compensate for water lost by excessive urination. Typically, people with undiagnosed diabetes will drink more sugary beverages, not just water, which drives the blood sugar higher.
  • Excessive urination (polyuria): The body tries to rid itself of extra sugar in the blood by dumping it via urine. Excessive urination can cause dehydration because a large amount of water is necessary to excrete high amounts of blood sugar.
  • Excessive eating (polyphagia): If able, the pancreas will secrete more insulin to control high blood sugar levels. With T2D, the body resists actions of insulin. One action of insulin is to stimulate hunger. Therefore, higher insulin levels can increase hunger. Despite eating more, the person with diabetes may gain very little weight and may even lose weight.
  • Poor healing or slowly-healing wounds: White blood cells are critical to defend the body against infection and also to clean up dead tissue. High blood sugar levels prevent white blood cells from functioning normally. When white blood cells do not function properly, wounds take much longer to heal and become infected more frequently. Long-standing diabetes is also associated with thickening of blood vessels, which prevents good circulation needed to deliver oxygen and other nutrients throughout the body.
  • Infections: Diabetes can suppress the immune system. Certain infections may indicate poor blood sugar control and can occur more often in a person with diabetes. These include frequent yeast infections of the genitals, dental infections, skin infections, and frequent urinary tract infections.
  • Altered mental status: Agitation, unexplained irritability, inattention, extreme lethargy, or confusion can all be signs of high blood sugar, or ketoacidosis, or hyperosmolar hyperglycemia nonketotic syndrome (“HONK” syndrome), or hypoglycemia (low blood sugar). Thus, any of these in a diabetic person merit immediate medical assessment of blood glucose. Call your health care professional or 911 for immediate attention by a medical professional.
  • Blurry vision: Though not specific for diabetes, blurry vision frequently occurs with high blood sugar levels.

When Should Someone Seek Medical Care for Type 1 or Type 2 Diabetes?

If a person has diabetes and experiences any of the following, contact a health care professional.

  • Experiencing diabetes symptoms. This may indicate an uncontrolled blood sugar level despite treatment.
  • Blood sugar levels are consistently high (more than 200 mg/dL). Chronically high blood sugar level is the root cause of all complications from diabetes.
  • Blood sugar level is often low (less than 70 mg/dL), called hypoglycemia. This may indicate that the diabetes management strategy is too aggressive. Hypoglycemia could also indicate infection or other stress on the body's organs, such as kidney failure, liver failure, adrenal gland failure, other conditions, or the concomitant use of certain medications.
  • Injury to the foot or leg, no matter how minor. Even the tiniest cut or blister can become seriously infected in a person with diabetes. Early diagnosis and treatment of problems affecting the feet and lower extremities, along with regular diabetic foot care, are critical to preserve function of the legs and to prevent amputation. Each person with long-standing diabetes must perform self-care by examining their feet daily for wounds. A person can use a mirror or smartphone on a selfie stick to inspect or document the bottoms of his or her own feet.
  • Low-grade fever (below 101.5 F or 38.6 C). Fever can be one sign of infection. Many common infections can potentially be more dangerous for diabetic people than non-diabetic people. Note symptoms may indicate where the infection is located, such as painful urination, redness or swelling of skin, abdominal pain, chest pain, or cough.
  • Nausea or vomiting despite keeping liquids down. The health care professional may adjust medications while the patient is sick. The health care professional will probably recommend an urgent office visit or a visit to the emergency department. Persistent nausea and vomiting can be a sign of diabetic ketoacidosis (DKA) or other serious illnesses. DKA can threaten life.
  • Small sore(s) or ulcer on the foot or leg. Any non-healing sore or ulcer on the feet or legs of a diabetic person must be evaluated by a medical professional. Even a sore less than 1 inch wide, not draining pus, and not exposing deep tissue or bone should be evaluated by a health care professional.

When you contact a health care professional, tell the person you are concerned because you or someone you know has diabetes.

  • The patient will probably be referred to a nurse who will ask questions and initially recommend what to do.
  • Be prepared for this conversation. Have handy by the phone a list of all medications and nutritional supplements, medical problems, allergies to medicines, and a blood sugar diary.
  • The nurse may need any or all of this information to decide both the urgency of the patient's condition and how best to treat the problem.

Diabetes Emergencies

Medical emergencies that warrant a call to 911

The following situations can become medical emergencies (call 911) and warrant an immediate visit to a hospital emergency department.

  • Anyone with a severe diabetic complication should travel to an emergency department by car or ambulance.
  • If the person is unable to speak for himself or herself, a companion should accompany him or her to speak with the health care professional.
  • Always bring a complete and current list of medical problems, medications, nutritional supplements, allergies to medications, and the person's blood sugar diary to the emergency department. This information will help the health care professional diagnose the problem and treat it appropriately.

Signs and symptoms of diabetic complications that warrant emergency care

  • Altered mental status: Lethargy, agitation, forgetfulness, or just strange behavior can be a sign of low or high blood sugar levels.
    • If a person with diabetes has an altered mental status, then try giving him or her some fruit juice (about 6 ounces) or cake icing if the person is awake enough to swallow normally without choking. Avoid giving things that can lodge in the throat, such as hard candy. The health care professional can prescribe glucose wafers or gels that melt under the tongue or glucagon (a medication given into the nose or by injection).
    • If a diabetic person does not wake up within about 5 minutes and behave normally within about 15 minutes, call 911.
    • If the person is not known to have diabetes, these symptoms can be signs of stroke, drug intoxication, alcohol intoxication, oxygen starvation, and other serious medical conditions. Call 911 immediately.
  • Nausea or vomiting: If a diabetic person cannot keep down food, medications, or fluids at all, he or she may have diabetic ketoacidosis, hyperosmolar hyperglycemic nonketotic (HONK) syndrome, or another complication of diabetes.
    • If he or she has not already taken his or her latest insulin dose or oral diabetes medicine, then contact a medical professional.
    • If he or she already has low blood sugar levels, taking additional insulin or medication may drive the blood sugar level down even further, possibly to dangerous levels.
  • Fever above 101.5 F (38.6 C): If the primary health care professional cannot see the patient right away, seek emergency care for a person with diabetes and high fever. Note any other symptoms such as cough, painful urination, abdominal pain, or chest pain.
  • High blood sugar level: If the person’s blood sugar level is above 400 mg/dL, and the primary health care professional cannot see him or her right away, go to the closest emergency department. High blood sugar levels can be a sign of DKA or HONK syndrome. Both conditions can be fatal if not treated promptly.
  • Large sores or ulcers on the feet or legs: For a diabetic person, a nonhealing sore larger than 1 inch in diameter can be a sign of a potentially limb-threatening infection.
    • Other signs and symptoms that merit immediate care are exposed bone or deep tissue wound, large areas of surrounding redness and warmth, swelling, and severe pain in the foot or leg.
    • Left untreated, such a sore may ultimately require amputation of the limb.
  • Cuts or lacerations: Any cut penetrating all the layers of skin, especially on the legs, is a potential danger to a person with diabetes. Although important to anyone's recovery, proper wound care is critical in diabetic people to assure proper wound healing.
  • Chest pain: Take seriously any pain in the chest or arms (particularly in the middle of the chest or along the left side), and immediately seek medical attention.
    • Diabetic people are more likely than nondiabetic people to have a heart attack, with or without experiencing chest pain.
    • Irregular heartbeats and unexplained shortness of breath may also be signs of heart attack.
  • Severe abdominal pain: Depending on the location, this can be a sign of heart attack, abdominal aortic aneurysm (dangerous widening of the large artery in the abdomen), DKA, or interrupted blood flow to the bowels.
    • All these are more common in people with diabetes than in the general population. All are potentially life-threatening.
    • People with diabetes also get other common causes of severe abdominal pain, such as appendicitis, perforated ulcer, inflammation and infection of the gallbladder, kidney stones, and bowel obstruction.
    • Severe pain anywhere in the body is a signal for timely medical attention.

What Tests Do Health Care Professionals Use to Diagnose Diabetes?

Doctors use common tests to diagnose diabetes and monitor blood sugar control.

The health care professional will take a history including information about the patient's symptoms, risk factors for diabetes, past medical problems, current medications, allergies to medications, family history of diabetes, or other medical problems (such as high cholesterol or heart disease), and personal habits and lifestyle.

Various laboratory tests can confirm the diagnosis of diabetes.

Fingerstick blood glucose at the point of care. This rapid test may be performed anywhere, including community-based screening programs.

  • Although not as accurate as testing blood in a hospital laboratory, a fingerstick blood glucose test is easy to perform, and the adequate result is available quickly.
  • The test involves sticking the patient's finger for a tiny blood sample. The blood drop is placed on a strip to be inserted into a machine that reports the blood sugar level. These portable machines are accurate to within about 10%-20% of true laboratory values.
  • Fingerstick blood glucose values tend to be most inaccurate at very high or very low levels. Abnormally low or high results should be confirmed by repeat testing. Point-of-care testing is how most people with diabetes monitor their blood sugar levels at home.

Fasting plasma glucose. The patient will be asked to eat or drink nothing for eight hours before having blood drawn, usually first thing in the morning. If the blood glucose level is greater than or equal to 126 mg/dL (without eating anything) at any age, the person probably has diabetes.

  • If the result is unclear, further testing may be performed to confirm diabetes. Such testing can be a fasting plasma glucose repeated on a different day, an oral glucose tolerance test (described below), or a fingerstick glycosylated hemoglobin (called "hemoglobin A1c" and described below).
  • If fasting plasma glucose level is greater than 100 mg/dL but less than 126 mg/dL, then the patient has impaired fasting glucose, or IFG. IFG is prediabetes. Though patients with IFG do not yet have diabetes, they carry high risk of developing diabetes in the near future.

Oral glucose tolerance test. After fasting for at least six hours, the health care professional draws blood to measure plasma glucose before and at two hours after drinking a specific sweet drink (which contains up to 75 grams of sugar).

  • If the blood sugar level rises to 200 mg/dL or higher, the patient has diabetes.
  • If the blood glucose level rises to between 140 and 199 mg/dL after the sugary drink, then the patient has impaired glucose tolerance (IGT). IGT is also a prediabetic condition.

Glycosylated hemoglobin or hemoglobin A1c. This test measures how high the blood sugar levels have been over approximately the last 120 days, which is the average life span of the red blood cells on which this test is based.

  • Glucose attaches naturally on hemoglobin in red blood cells and stays there for the remaining life of the red blood cell.
  • The percentage of hemoglobin with attached sugar can be measured in a small blood drop, obtained by fingerstick or blood draw.
  • The hemoglobin A1c test is a practical measure of blood sugar control in most people with diabetes. The normal hemoglobin A1c value is under 6%. Hemoglobin A1c levels at or below 7% indicate good glucose control. Results at or above 8% indicate blood sugar levels are high too often.
  • The hemoglobin A1c test is most useful for diabetes follow-up care. Though occasionally suboptimal for diagnosing diabetes, hemoglobin A1c above 6% is highly suggestive of diabetes. Often another test will support the diagnosis of diabetes.
  • The hemoglobin A1c is usually measured about every three to six months in people with diabetes. It may be done more frequently for people with difficulty achieving and maintaining good blood sugar control.
  • This test is rarely used to document chronic hypoglycemia in nondiabetic patients.
  • Normal values may vary from laboratory to laboratory.

What Are Diabetes Treatment Options?

Various treatments exist for diabetes. T1D requires insulin (by multiple daily injections or a pump), diabetic diet, and other lifestyle modifications. T2D is generally treated with diabetic diet, lifestyle changes (such as moderate to vigorous exercise), and medication(s).

Are There Home Remedies (Diet, Exercise, and Glucose Monitoring) for Diabetes?

If a person has diabetes, healthful lifestyle choices in diet, exercise, sleep, and other habits will help improve glycemic (blood sugar) control and prevent or minimize complications from diabetes.

Diabetes diet

A healthy diet is key to controlling blood sugar levels and preventing diabetes complications.

  • Patients who are obese and have had difficulty losing weight on their own should talk to a health care professional. He or she can recommend a dietitian, help set feasible goals, or supervise a weight-modification program.
  • Eat a consistent, well-balanced diet high in fiber, low in saturated fat, low in concentrated sweets, and eliminate excess calories.
  • A consistent diet includes roughly the same number of calories at predictably similar times of day. Such a disciplined diet helps match the correct dose of insulin or other medications.
  • A healthy diet helps keep the blood sugar level relatively even. A healthy, predictable diet avoids excessively low or high blood sugar levels, which can be dangerous and even life-threatening.


In any form, regular exercise helps reduce the risk of developing diabetes. Activity can reduce the risk of developing diabetes-related complications such as heart disease, stroke, kidney failure, blindness, and leg ulcers.

  • As little as 20 minutes of walking three times a week has proven beneficial. Any exercise is beneficial. No matter how easy or how long, some exercise is better than no exercise. Reducing the time spent sitting is helpful.
  • Patients who have diabetes-related complications (such as eye, kidney, or nerve problems) may be limited in both the type of exercise and the amount of exercise they can safely perform. Consult your health care professional before starting any exercise program.

Alcohol use

Moderate or eliminate alcohol consumption. One drink is considered 1.5 ounces of liquor, 6 ounces of wine, or 12 ounces of beer. Adult men should not consume more than seven alcoholic drinks in a week, and never more than two drinks in an evening. Adult women should not consume more than three alcoholic drinks in a week, and never more than one drink in an evening. Excessive alcohol use is a known risk factor for T2D. Alcohol consumption can cause low or high blood sugar levels, cause nerve pain (neuritis), and increase blood triglycerides.


If a diabetic person smokes cigarettes or uses any other form of tobacco, he or she dramatically raises his or her risks for nearly all diabetes-related complications. Smoking damages blood vessels. Smoking contributes to heart disease, stroke, and poor circulation in the limbs. People who need help to quit tobacco use should talk to a health care professional.

Self-monitored blood glucose

Check blood sugar levels frequently, then record the results in a logbook or digital record. At a minimum, check blood sugar before meals and at bedtime.

  • The glucose log should include the doses and times of administration for insulin or oral medications, when and what the person ate, when and for how long the person exercised, and any significant events of the day (such as high or low blood sugar levels and how the person treated the problem). Many mobile applications ("apps") exist to help log and share data.
  • Simple equipment exists to test sugar levels less painfully and more conveniently. The daily sugar diary is invaluable both to self-management and to professional evaluation of responses to medications, diet, and exercise.
  • Medicare pays for diabetic testing supplies, as do many private insurers and Medicaid.
  • Continuous glucose monitors (CGMs) are useful devices that measure and log glucose levels under the skin. CGMs and their logs can be highly helpful tools for managing diabetes. CGMs must be calibrated carefully with blood glucose monitoring.

What Are Medical Treatments for Diabetes?

Treatment of diabetes is highly individualized. Treatment depends on the specific type of diabetes, co-existing medical problems, presence of diabetes-related complications, and the physical and mental skills of the affected person.

  • A health care team helps set healthy and feasible goals for lifestyle changes, blood sugar control, and treatment.
  • Together, the affected person and his or her health care team formulate a plan to help meet these goals.

Education about diabetes and its treatment is essential.

  • At the initial diagnosis of diabetes, the health care team will spend much time educating the patient about the condition, treatment, and practical skills for daily self-care.
  • The diabetes care team includes the health care professional and support staff. A professional dietitian and a diabetes educator are usually part of the team. The team may include specialists in hormone health (endocrinology), foot care (podiatry), neurology, kidney diseases (nephrology), eye diseases (ophthalmology), and behavioral health (psychology or psychiatry).
  • Among reputable sources, the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK) provides information on diabetes and related research including clinical trials.

The health care team will encounter the patient at appropriate intervals to monitor progress and evaluate goals.

Type 1 diabetes treatments

Treatment of T1D involves multiple daily injections of insulin or continuous insulin delivery by a pump. Daily injections usually combine short-acting insulin (e.g., lispro [Humalog], aspart [NovoLog or Fiasp], regular) and a long-acting insulin (e.g., NPH, lente, glargine [Lantus or Basaglar], detemir [Levemir]).

  • Insulin must be given as an injection just under the skin. If taken by mouth, insulin would be destroyed in the stomach before it could get into the blood where it is needed.
  • Most people with T1D inject themselves. Even if someone else usually injects the insulin, every person taking insulin must know how to inject insulin in case the other person is unavailable.
  • A trained professional will show the patient how to store and inject insulin. Usually this is a nurse or a diabetes educator.
  • Fast-acting insulin is usually injected three or four times each day, generally around mealtimes. Dosage is individualized and tailored to the patient's specific needs. Long-acting insulin formulations are typically administered once or twice each day.
  • Some people prefer to receive fast-acting insulin continuously by infusion pumps. Supplemental mealtime insulin is programmed into the pump by the individual in consultation with his or her health care team.
  • It is important to match food intake with insulin dosing, because insulin lowers blood sugar regardless of whether a person eats or not. If excessive insulin is received relative to food intake, the result may be hypoglycemia. This is called an insulin reaction.
  • During the adjustment period after initial diagnosis, the individual learns how insulin affects him or her. He or she learns how to time meals and exercise with insulin injections to keep blood sugar levels as even as possible. Many people with diabetes struggle with adjustment to their condition, especially maintaining high motivation and resilience after many years coping with diabetes.
  • Keeping accurate records of sugar levels and insulin dosages is crucial for diabetes management.
  • Eating a consistent, healthy diet appropriate for the patient's diagnosis and weight is essential to control sugar levels and to prevent diabetes-related complications.

Type 2 diabetes treatments

Depending on several factors upon diagnosis of T2D, the person may be able to control blood sugar through lifestyle changes, without medication. Such factors include but are not limited to the patient’s age, motivation, self-discipline with diet and exercise, duration of T2D prior to clinical diagnosis, and co-existing conditions.

  • For obese people with T2D, the best initial approach includes dietary restrictions and an exercise program under the supervision of a physician with the aim of weight loss.
  • This course will generally be tried for three to six months. If blood sugar and glycosylated hemoglobin remain high, then the person will receive oral medication, usually a sulfonylurea or biguanide (metformin [Glucophage]).
  • Even on medication, a healthy diet and physical activity are essential to lose weight or to maintain a healthy weight. People should perform moderate to vigorous physical activity as often as possible.
  • The health care professional will carefully monitor the patient's progress on medication. The therapeutic goals are the right dose(s) of the right medication(s) at the right time(s) to control blood sugar levels with few side effects.
  • Over time, people with T2D often require insulin injections to control their sugar levels.
  • People with T2D commonly take a combination of oral medication and insulin injections to control sugar levels.

What Medications Treat Diabetes?

Many different types of medications are available to help lower blood sugar levels in people with T2D. Each medication works in a different way. Combining two or more medications commonly gets better outcomes.

  • Sulfonylureas: These stimulate the pancreas to release more insulin. Sometimes, the pancreas lacks enough stored insulin to respond adequately to sulfonylurea.
  • Biguanides: These decrease the amount of glucose produced by the liver by improving its sensitivity to insulin.
  • Alpha-glucosidase inhibitors: These slow absorption of starch as a person eats, which slows down the rise of blood glucose level during and after meals.
  • Thiazolidinediones: These increase tissue sensitivity to insulin but are restricted in the U.S. market.
  • Meglitinides: These stimulate the pancreas to release more insulin.
  • D-phenylalanine derivatives: These stimulate the pancreas to release more insulin more quickly.
  • Sodium-glucose co-transporter 1 (SGLT2) inhibitors: These block reabsorption of glucose by the kidney, leading to increased glucose excretion and reduction of blood sugar levels. Urinary tract infections are more common with SGLT2 inhibitors due to higher sugar levels in the urine.
  • Amylin synthetic derivatives: Amylin is a naturally occurring hormone secreted by the pancreas along with insulin. Amylin derivatives, such as pramlintide (Symlin), help lower blood sugar levels after meals when insulin alone does not. Pramlintide is injected subcutaneously along with insulin.
  • Incretin mimetics: These promote insulin release by the pancreas. They mimic other natural actions that lower blood sugar level. Exenatide (Byetta) was the first incretin mimetic agent approved in the U.S. It is indicated for T2D in addition to metformin (Glucophage) or a sulfonylurea, when these agents alone cannot control the sugar level.
  • Insulins: Only synthetic types of human insulin are available in the U.S., since they are less likely to cause allergic reactions than the animal-derived insulin used in the past. Different formulations of insulin are categorized according to action onset and duration. Commercial mixtures of insulin sometimes provide constant (basal) control and immediate control.

What Are Complications of Diabetes?

Both T1D and T2D create high blood sugar levels, called hyperglycemia. Over years, hyperglycemia damages the retina of the eye, blood vessels of the kidneys and other organs, and the nerves.

  • Damage to the retina from diabetes (diabetic retinopathy) is the leading cause of acquired blindness.
  • Damage to the kidneys from diabetes (diabetic nephropathy) is the leading cause of acquired kidney failure.
  • Damage to the nerves from diabetes (diabetic neuropathy) is a major cause of foot wounds and ulcers. It remains the leading cause of nontraumatic amputations of feet and legs.
  • Damage to the nerves in the autonomic nervous system can lead to paralysis of the stomach (gastroparesis), chronic diarrhea, and an inability to control heart rate and blood pressure during postural changes (dysautonomia).
  • Diabetes accelerates atherosclerosis, (the formation of fatty plaques inside the arteries), which can lead to blockages or a clot (thrombus). Such changes can then lead to heart attack, stroke, and decreased circulation in the arms and legs (peripheral vascular disease).
  • Diabetes predisposes people to elevated blood pressure (hypertension), high levels of cholesterol and triglycerides. Both independently and together with hyperglycemia, these conditions increase the risk of heart disease, kidney disease, and other blood vessel complications.

Diabetes can contribute to a number of acute medical problems. Acute means coming on suddenly rather than developing slowly over time (chronic).

  • Many infections are associated with diabetes. Infections are frequently more dangerous in someone with diabetes because the body's normal ability to fight infections is impaired. Infections may worsen glucose control, which further delays recovery from infections.
  • Hypoglycemia or low blood sugar occurs intermittently in most people with diabetes. It can result from receiving too much diabetes medication or insulin (an insulin reaction), missing a meal, exercising more than usual, drinking too much alcohol, or taking certain medications for other conditions. You should recognize hypoglycemia and must be prepared to treat it at any time. Headache, feeling dizzy, poor concentration, tremor of the hands, and sweating are common symptoms of hypoglycemia. A person can faint or lose consciousness with a seizure if blood sugar level becomes too low.
  • Diabetic ketoacidosis DKA is a serious condition in which uncontrolled hyperglycemia causes dehydration and inadequate insulin allows buildup of blood ketones (acidic waste products). High acid and altered salt levels in the blood can threaten life. DKA typically occurs at the initial diagnosis of T1D and in people with poor glucose control. DKA can be precipitated by infection, stress, trauma, missing medications like insulin, or medical emergencies such as a stroke or heart attack.
  • Hyperosmolar hyperglycemic nonketotic (HONK) syndrome is a serious condition in which high blood sugar level leads to severe dehydration. When the body tries to rid its excess sugar via the urine, this can cause severe dehydration leading to seizures, coma, and even death. HONK syndrome typically occurs in people with T2D who are not controlling their sugar levels, who have become dehydrated, or who have stress, injury, stroke, or are taking certain medications, like steroids.

Diagnosing Diabetes-Related Complications

A person with diabetes should be checked regularly for early signs of diabetic complications. A primary health care professional can order some tests. Other tests require referral to a specialist.

  • People with diabetes who have entered or passed puberty should have their eyes checked at least once a year by an eye specialist (ophthalmologist) to screen for diabetic retinopathy, a leading cause of acquired blindness.
  • The urine should be checked for protein (microalbumin) on a regular basis, at least once annually. Urinary protein is an early sign of diabetic nephropathy, a leading cause of acquired kidney failure.
  • Sensation in the legs should be checked regularly using a tuning fork or a monofilament device. Diabetic neuropathy is a leading cause of lower extremity ulcers in individuals with diabetes and the leading contributor to nontraumatic amputations of the feet or legs.
  • The health care professional should check the feet and lower legs of adult diabetic patients at every visit for cuts, scrapes, blisters, or other lesions that could become infected. Adults with diabetes should check the soles of their feet and their legs daily with a hand-held mirror or camera, either themselves or with the assistance of a relative or caretaker.
  • The adult patient should be screened regularly for conditions that may contribute to heart disease, such as high blood pressure and high cholesterol.

Diabetes Follow-up


  • Follow treatment recommendations of your health care team.
  • Keep records of blood sugar levels or CGM results as often as recommended by your health care team, including times when levels were checked, when and how much insulin or medication was taken, when and what was eaten, and when and for how long the patient exercised.
  • Contact your health care professional if you have issues with treatment or symptoms suggesting poor glucose control.
  • Fast-acting glucose should always be available for emergency use in case of hypoglycemia.
  • Glucagon should always be available for emergency use by the patient or patient's support in case of seizure or unconsciousness suspected to be due to hypoglycemia.
  • People with diabetes should always wear a medical identification tag that identifies their diagnosis and shows contact information for their healthcare provider. For children with diabetes, it is appropriate to show contact information for the parent(s).


  • Attend diabetes education classes at the local hospital. The more educated you and your family are about your diabetes, the better your health is likely to be.
  • If taking insulin, you should see your health care professional about every three months at a minimum. Every three to six months is generally adequate for those with uncomplicated diabetes and not taking insulin.
  • Become educated to recognize the signs and symptoms of low blood sugar levels. Have a clear plan for treating low blood sugar levels, and know when to call 911. Mild symptoms include confusion and sweating. These symptoms can progress to lethargy, agitation (sometimes with violent, jerking motions), or seizures.

Is It Possible to Prevent Diabetes?

No approach has yet been approved by the FDA to prevent T1D, though recent research showed promising results for teplizumab for some at highest risk of developing T1D.

T2D can be prevented in some cases.

  • Control weight to normal or near-normal levels by eating a healthy low-fat, high-fiber diet with appropriate content of calories.
  • Regular physical activity is essential to prevent T2D.
  • Keep alcohol consumption low.
  • Quit smoking and other tobacco products.
  • To control high blood fat levels (e.g., high total cholesterol) or high blood pressure, take medications as directed.
  • Lifestyle modifications and/or certain medications can sometimes prevent progression of prediabetes to T2D. Prediabetes can be diagnosed by checking fasting glucose or two hours after ingesting up to 75 grams of glucose (dose based on patient’s weight).

If you or someone you know has any type of diabetes, focus on preventing diabetes-related complications. Complications can cause serious disabilities, such as blindness, kidney failure requiring dialysis, amputation, or even death.

  • Tight glucose control! The single best thing people with diabetes can do is to keep their blood sugar level within the suggested range every day. The only way to accomplish this goal is the combination of glucose monitoring, appropriate diet, high personal motivation sustained over time, and appropriate medical treatment. Consult a nutritionist or your health care professional regarding diet.
  • Quit smoking and stop use of other tobacco products.
  • Maintain healthy weight.
  • Increase physical activity. Adults should aim for moderate to vigorous physical activity lasting at least 30 minutes every day.
  • Drink adequate amounts of water, and avoid consuming excessive salt.
  • Take care of your skin. Keep it supple and hydrated to avoid sores and cracks that can become infected.
  • Brush and floss your teeth at least twice every day. Encounter your dentist and dental hygienist regularly to prevent tooth decay and gum disease.
  • Wash and examine your feet daily. Including the soles, look for small cuts, sores, or blisters that may worsen. File toenails to avoid damaging the surrounding skin, rather than cutting them. A specialist in foot care (podiatrist) may be necessary to help care for your feet.

What Is the Prognosis of Diabetes?

Diabetes is a leading cause of death in all industrialized nations. Overall, the risk of premature death of people with diabetes is twice that of people without diabetes. Prognosis depends on the duration of diabetes, degree of blood sugar control, and development of complications.

Type 1 diabetes

About 15% of people with T1D die before age 40 years, which is about 20 times the rate of this age group in the general population.

  • Diabetic ketoacidosis (DKA), kidney failure, and heart disease compose the most common causes of death related to T1D.
  • The good news is prognosis improves with good sugar control. Maintaining tight blood (or CGM) sugar control prevents, slows the progression of, and can improve established complications of T1D.

Type 2 diabetes

The life expectancy of people who are diagnosed with T2D during their 40s decreases by five to 10 years because of the disease.

  • Heart disease leads the causes of death related to T2D.
  • Aim for excellent glycemic control, tight blood pressure control, keeping the "bad" cholesterol (LDL) level at the recommended level below 100 mg/dL (or even lower, particularly if other risk factors for cardiovascular disease are present), and keeping the "good" (HDL) cholesterol as high as possible. When indicated, aspirin can prevent, slow the progression of, and improve established complications related to diabetes.

What Types of Health Care Professionals Treat Diabetes?

Most primary care providers have experience managing diabetes, including internists, gynecologists, and family practitioners. Specialists in diabetes care are called endocrinologists or diabetologists. You can locate endocrinologists using the "Find an Endocrinologist" search engine online at the Hormone Health Network. You can locate a pediatric endocrinologist for diabetic youth using the "Find a Doctor" search engine of the Pediatric Endocrine Society.

Are There Support Groups and Counseling for People With Diabetes?

Consider joining a support group to share your experiences and learn from others. The American Diabetes Association, Hormone Health Network, and local chapters of Juvenile Diabetes Research Foundation International are excellent resources. Your health care team will have information about local groups in your area. The following groups also provide support:

American Association of Diabetes Educators
100 W Monroe, Suite 400
Chicago, IL 60603
(800) 338-3633

American Dietetic Association
120 South Riverside Plaza, Suite 2000
Chicago, IL 60606-6995
(800) 877-1600

National Diabetes Education Program
One Diabetes Way
Bethesda, MD 20814-9692
(800) 438-5383
[email protected]

Hormone Health Network
2055 L Street NW, Suite 600
Washington DC 20036
[email protected]

Non-starchy vegetables make up a large portion of the diet of those with type 2 diabetes.

Type 2 Diabetes Diet

A healthy eating plan is an essential part of any diabetes treatment plan, but there is no one recommended "diabetic diet" for everyone. An individual nutrition plan will depend on many things, including underlying health and level of physical activity, the types of medication(s) being taken, and personal preference. Most people with type 2 diabetes find that having a fairly regular schedule for meals and snacks is helpful. Eating a variety of foods and watching portion sizes is also recommended.

Examples of meal planning tools that some people with type 2 diabetes like to use include

  • the plate method,
  • carbohydrate counting, or the
  • glycemic index.
MedscapeReference.com. Type 2 Diabetes Mellitus.