Insulin is a hormone that regulates the body’s metabolism, helping control both the storage and utilization of the major energy sources in the blood, glucose (the most important energy source) and lipids (fats, sterols, certain vitamins, other substances). Simplistically, insulin increases the use of glucose and inhibits the use of fat as an energy source. Insulin is produced in the pancreas and is released into the bloodstream in response to increasing levels of blood glucose as well as from other signals.
The human body regulates its most important systems by having both ‘on’ and ‘off’ mechanisms working in concert, allowing rapid and precise control in response to stimuli. Balancing insulin are epinephrine (also called adrenalin), noradrenaline and cortisol which are made in the adrenal glands and are part of the body’s response to stress (for example infections, fight or flight response, many other causes), glucagon (made in the pancreas), growth hormone (made in the pituitary gland in the brain), and other hormones and mechanisms.
Diabetes mellitus (DM) is a disorder of abnormal energy metabolism, resulting in abnormally high blood glucose and lipid levels. It is diagnosed based on glucose levels of greater than 126 mg/dl on two or more tests or by a single level greater than 200 mg/dl. Pre-diabetes (glucose intolerance) is diagnosed by morning glucose levels between 100 and 125 mg/dl or a level of 140 to 200 mg/dl two hours after ingesting a specific amount of glucose.
DM is a common chronic condition, affecting more than one in every ten Americans. Although over a million new cases of DM are diagnosed every year, many people with this condition are unaware that they have it.
More than 55 million Americans have prediabetes. This does not necessarily lead to diabetes; the Diabetes Prevention Program showed that with certain lifestyle changes, including modest weight loss, increased physical activity and behavior changes (reducing fat and salt intake), progression to DM can be delayed or averted in over 50 percent of pre-diabetics.
Fatigue and slow wound healing are early, but non-specific, DM symptoms. High glucose levels may overwhelm the kidney’s ability to reabsorb all the glucose, so glucose is ‘spilled’ into the urine causing an increased need to urinate (polyuria) and increased thirst (polydipsia).
Complications of DM may include:
Kidney failure: DM is the leading cause of kidney failure, affecting more than 45,000 Americans per year.
Peripheral neuropathy: about two-thirds of diabetics develop this nerve condition causing pain and numbness in the feet and/or hands. This, in addition to the poor blood circulation and poor wound healing, makes DM the leading cause of non-traumatic amputations.
Cardiovascular disease: diabetics have a two to four times higher risk of dying from a heart attack, and up to eight times higher risk of dying from a stroke.
Death: diabetes is the seventh leading cause of death in the U.S.
Other: DM is a leading cause of blindness, dental problems and problems during pregnancy.
DM is characterized into several types:
Type II DM, which accounts for 90 to 95 percent of all cases of DM, is due to the body's cells becoming resistant to insulin, so patients need higher levels of insulin to regulate their blood glucose. It runs in families and is more common in certain ethnic groups (for example African Americans). Risk factors include being overweight, sedentary lifestyle and having a poor diet; the increase of these in our population has doubled the incidence of Type II DM over the last 10 years. About 60 percent of Type II diabetics are controlled with oral medications (pills) that help their system increase its insulin production and better utilize insulin. Ten to 15 percent use only insulin, another 10 percent to 15 percent use insulin and pills, and the rest use diet modification without medications.
Type I DM (the more common type in childhood) accounts for 5 to 10 percent of all diabetics and is caused by failure of the pancreas to produce insulin, usually due to an autoimmune reaction (the body attacks its own pancreas cells). It occurs sporadically, does not run in families, and no specific risk factors or triggers have been identified. These patients require insulin injections to survive.
Gestational DM is an abnormality of glucose metabolism triggered by changes during pregnancy, affecting 3 to 10 percent of pregnancies. The American Diabetes Association (ADA) recommends that women should be screened for DM during pregnancy. Adequate treatment (determined specifically for each pregnant diabetic) can help prevent complications (such as fetal death, premature delivery, abnormally large birth weight, low blood sugar for the baby immediately after delivery, others). Although most women who develop gestational DM have their glucose levels return to normal after delivery, their lifetime risk for developing DM is higher.
Diabetics must follow a careful diet, closely regulating their caloric intake. They need to monitor their blood glucose and adhere to their medications. Regular exercise, under the guidance of a healthcare professional, is also important. Many new therapies have been developed, including glucose pumps, implantable glucose monitors, and many new medications.
To prevent/identify possible complications, regular checkups including annual eye examinations, measurement of HgbA1c (a blood test that can measure ‘average’ levels of glucose to determine if a patient’s blood sugars are overall well controlled) two to four times per year, foot examinations, dental examinations, blood pressure monitoring, cholesterol monitoring and urine checks are recommended.
You can estimate your own risk of developing diabetes at reference.medscape.com/calculator/diabetes-risk-score-type-2?src=ppc_google_rsla_ref&gclid=CLL4it-SktACFdgPgQodwUoGMg or diabetes.org/are-you-at-risk/diabetes-risk-test/ . In addition, the ADA at diabetes.org is a great resource for more information.
Jeff Hersh, Ph.D., M.D., can be reached at DrHersh@juno.com