Gestational diabetes (strawberry) is a temporary form of diabetes caused by insulin resistance that develops during pregnancy. Women with gestational diabetes usually require insulin to control their blood sugar levels. This is because oral medications pass through the placenta and may affect the baby’s development. After delivery, when the production of insulin-opposing hormones drops off and weight comes down quickly, most of these new moms cease to need insulin injections. However, their risk for developing type 2 diabetes later in life is markedly increased. This is due to an underlying susceptibility to insulin resistance coupled with insufficient insulin production to overcome the resistance.
MODY (marshmallow) stands for maturity-onset diabetes of the young. Unlike type 2 diabetes, which is typically caused by insulin resistance, a genetic defect that limits the pancreas’s ability to secrete sufficient amounts of insulin causes MODY. MODY is not associated with being overweight or obese. It is frequently diagnosed during early puberty, perhaps due to the increased demand for insulin that pubertal hormone production causes. Depending on how defective the beta cells become, oral medications or insulin may be required to treat MODY.
LADA (mint chocolate chip) refers to latent autoimmune diabetes of adulthood. Think of it as an incomplete, slowly developing form of type 1 diabetes that is compounded by mild to moderate insulin resistance. Some people call it “type 1½” because it shares characteristics with both type 1 and type 2. In LADA the immune system attacks the beta cells of the pancreas, but the attack is incomplete. Many beta cells survive and continue to secrete insulin, sometimes for years. Many people with LADA can manage their blood sugar with oral medications or low doses of insulin for a period of time, but eventually true insulin dependence develops and treatment requires intensive insulin therapy.
Neonatal diabetes (butter pecan) is a rare form of diabetes that occurs in the first six months of life. Similar to MODY, neonatal diabetes involves an inherited genetic mutation that limits the beta cells’ ability to produce insulin. In some cases, neonatal diabetes disappears during infancy but then reappears later in life. In other cases, diabetes persists and remains permanent. Insulin is almost always required to treat neonatal diabetes and promote healthy growth and development.
Unlike the gazillions of books that explore the many treatment options for type 2 diabetes, this book focuses purely on the use of insulin. As such, it applies to everyone with type 1 diabetes, secondary diabetes, and neonatal diabetes, those in the later stages of LADA, as well as millions who suffer from type 2 diabetes, gestational diabetes, or MODY.
Table 3-1. Meet the Diabeteses
Diabetes Type Cause(s) Treatment Options
Type 1 Autoimmune attack on beta cells of the pancreas Insulin
Type 2 Insulin resistance and progressive beta cell insufficiency Lifestyle changes, diabetes medications, insulin
Gestational Temporary insulin resistance Lifestyle changes, insulin
LADA Partial autoimmune attack on beta cells and some insulin resistance Insulin, possibly diabetes medications in early stages
Neonatal Genetic defect limiting beta cells’ ability to make insulin Insulin
MODY Genetic defect limiting beta cells’ ability to make insulin Lifestyle changes, diabetes medications, insulin
The Gold Standard: Nondiabetes
To “think like a pancreas” is to come as close as possible to matching a normal, nondiabetic state.
Regardless of whether you have diabetes, blood sugar comes from two sources: internal and external. Internal sources are sugars that are stored up in the liver and, to a lesser extent, the muscles. External sources are the foods we eat—mainly carbohydrates. Our bodies convert internal and external sugar into a specific type of sugar called glucose for circulation in the bloodstream.
Glucose is the preferred energy source for most cells of the body. Some cells, such as brain cells and nerve cells, will burn only glucose for energy. Thus, having a steady supply of glucose available in the bloodstream is very important.
Insulin’s job is to get glucose out of the bloodstream and into the body’s cells so that it can be burned for energy. Besides helping get sugar out of the bloodstream and into the body’s cells, insulin has another job: blocking the release of sugar from the liver and muscles. Instead, insulin packs sugar into the liver and muscles for use at another time.
When a person without diabetes has not eaten for a while, the blood sugar level can begin to drop. This can occur between meals, during sleep, and during exercise. When the blood sugar begins to drop, the pancreas decreases its production of insulin and increases its production of another hormone, glucagon. This reduces the amount of sugar being taken out of the bloodstream and stimulates the liver to release some of its stored-up sugar. As a result, blood sugar levels don’t go too low.
In a way, the pancreas acts like a thermostat that keeps your house comfy-cozy. When the temperature goes up, the thermostat kicks on the fan and air conditioner. When the temperature goes down, the thermostat kicks on the heat. Either way, the temperature stays within a comfortable range.
In your body, when the blood sugar level begins to rise, the pancreas secretes extra insulin, which brings the blood sugar level down. When the blood sugar starts to dip a bit, the pancreas eases back on insulin production and begins producing glucagon, which brings the blood sugar back up. This system helps keep the blood sugar within a range that is comfy-cozy for your body—approximately 60 to 110 mg/dl (3.3–6.1 mmol/l).
Truth be known, a better title for this book would be Think Like a Beta Cell, because it is this select group of cells that acts like our blood sugar thermostat. (But who would want to read a book with that title? Think Like a Pancreas sounds much more fun!) In fact, the beta cells do more than just measure glucose levels and secrete insulin; along with insulin, they also secrete a second hormone called amylin. Amylin’s job is to work with insulin, particularly at mealtimes, to keep blood sugar from spiking too high right after eating.
We will discuss amylin in more detail later. Let’s turn now to the factors that affect our blood sugar levels on a daily basis.
Blood Sugar Balancing: The Major Players
There are a few major factors that affect our blood sugar on a regular basis (see Table 3-2) and a number of minor factors that pop up on special occasions (see Table 3-6 later in this chapter). Learning to keep them all in balance is what ultimately keeps the blood sugar under control. Let’s start with the major factors.
Table 3-2. Major Factors Affecting Blood Sugar
Factor 1: Insulin
Insulin lowers blood sugar, plain and simple. However, the action of insulin varies depending on the type of insulin, its rate of absorption into the bloodstream, and the body’s sensitivity to the insulin.
Insulin is measured in units. A unit of insulin should lower the blood sugar the same amount no matter what kind of insulin you use. A unit of fast-acting insulin will lower your blood sugar the same as a unit of longacting insulin; it just does so in a shorter period of time. One exception is a long-acting basal insulin called detemir (brand name Levemir), which is approximately 25 percent less potent than other insulins.
Another exception occurs when the insulin concentration varies. Worldwide, most insulin is standardized as “U-100.” This means that there are 100 units of insulin in every cc (cubic centimeter) of fluid. In some instances, diluted (U-50) or concentrated (U-500) insulin can be found. Some people choose to dilute their insulin to allow dosing in more precise increments with standard insulin syringes. For example, a child who is very sensitive to insulin may have their insulin diluted to U-10 by mixing 90 units of neutral diluent with 10 units of insulin. The resulting mixture would be 10 percent as potent as normal U-100 insulin. One unit (as measured on an insulin syringe) would actually be equivalent to one-tenth of a unit of U-100 insulin.
A summary of insulin types is given below in Table 3-3. Be aware that the precise action times can vary from person to perso
n. And because insulin is injected (or infused, in the case of an insulin pump) into the fat below the skin, the exact onset, peak, and duration can vary from day to day or even meal to meal.
Premixed insulins, such as 75/25 and 70/30, contain a combination of NPH (intermediate-acting insulin) and either regular or rapid-acting insulin. For example, Humalog Mix 75/25 contains 75 percent NPH and 25 percent Humalog. Novolin 70/30 contains 70 percent NPH and 30 percent regular insulin.
The actions of the newer insulins (lispro, aspart, glulisine, glargine, and detemir) are not affected much by where on the body they are injected, but older-generation insulins (regular, NPH) can vary considerably depending on where they are injected. However, injecting any insulin into a body part that will be exercising may accelerate the action of the insulin, particularly when the exercise is performed within an hour of the injection. This is due to enhanced blood flow in the area that is being exercised. For example, injecting insulin into the thigh and then going for a jog may cause the insulin to start working faster, peak earlier, and finish working sooner than usual.
Table 3-3. Insulin action profiles
Injecting insulin into muscle will also accelerate its action. Rapidacting insulin, which normally takes three to five hours to finish working, can do its full work in ninety minutes or less when injected into muscle. This can cause a very rapid blood sugar drop, and it may produce hypoglycemia when given to cover a meal.
The action of NPH and regular insulin is more rapid in body parts that have greater blood flow. Injecting into the abdomen tends to produce the most rapid absorption, followed by the arms, then the legs, and finally the buttocks. When using older-generation insulins, be consistent about your injection sites. For example, always use the abdomen in the morning, thigh at dinner, and buttocks at bedtime. This will minimize the amount of variability in the insulin’s action from day to day.
Below are a few other tips to help ensure that your insulin works as expected.
Rotate your sites: A condition known as lipodystrophy can affect insulin action. Repeated injections or infusions into the same small area of skin can cause the fat below the skin to either swell and harden (lipohypertrophy) or wear away (lipoatrophy). In either case, the absorption of insulin will be altered. For this reason, it is best to rotate your injection and infusion sites over a large area of skin. If it helps, imagine that you have a monthly calendar printed on each of the body parts where you inject, and inject into the spot that corresponds with the day of the month.
Storage: Unopened insulin vials, pens, and cartridges should be stored in a refrigerator (but not frozen). This should keep your insulin fresh until the expiration date. The butter compartment on the door might make an ideal home for your insulin. Once a vial, pen, or cartridge is opened (i.e., the rubber stopper is punctured), it may be kept at room temperature for up to one month. Room-temperature insulin tends to form fewer bubbles in the syringe and is generally more comfortable to inject. Your insulin should be kept out of direct sunlight and away from heating devices. When ordering insulin through the mail, request that it be shipped in a thermally insulated package. When traveling, keep your insulin in a cushioned pouch and do not leave it in a non–air conditioned vehicle for more than a few minutes. Do not use insulin that has an unusual appearance. If it has crystals on the surface, residue at the bottom, an unusual color, or if it does not mix uniformly, it should be discarded.
Replacement: As a general rule, insulin vials, pens, and cartridges should not be used for more than one month. Under special circumstances, such as when traveling extensively or if you forget to refill your insulin prescription, it may be used for slightly longer than a month. However, don’t make a habit of it. Every time the rubber stopper is punctured, contaminants and impurities can find their way into your insulin and cause it to start losing potency. As a general policy, every month, discard whatever you have left and start fresh.
Proper mixing: NPH (cloudy) insulin, or any premixed insulin that contains NPH, needs to be rolled gently several times to ensure an even mixture prior to injection. NPH may be combined in the same syringe with regular or rapid-acting insulin. To ensure that your insulin is not contaminated during the mixing process, be sure to draw up the insulin in order from fastest to slowest. In other words, draw the clear (fast) insulin into your syringe before drawing in the cloudy (intermediate) insulin. If a tiny amount of fast-acting insulin gets into the vial of intermediate-acting insulin, it usually will not cause any harm. However, if intermediate-acting insulin gets into the vial of fast-acting insulin, it may contaminate the entire vial. Because of their slight acidic property, glargine (Lantus) and detemir (Levemir) should never be mixed with another insulin in the same syringe.
Spare the air: Whether you use syringes, pens, or a pump, eliminating large air bubbles is important. Very small (soda-sized) bubbles are not much of a concern, but larger bubbles can cause your insulin dose to be reduced significantly. Remember, room-temperature insulin is less likely to form bubbles. If air bubbles appear in your pen or syringe, you should inject them out through the needle (into the air) and then redraw your dose.
The right depth: Because insulin is meant to be injected into the fatty layer below the skin, selecting a needle that is the proper length is important. A needle that goes too deep may accidentally inject into muscle. Not only does an intramuscular injection tend to sting, but any form of intermediate or long-acting/basal insulin that is injected into muscle can act much too fast and cause severe hypoglycemia. Likewise, injections that are too shallow (barely below the skin surface) can hurt and may “pocket” under the skin, resulting in incomplete absorption and high blood sugar.
Remarkably, skin thickness is similar in children and adults (even obese adults)—just a couple of millimeters. It is safe and advisable to use injection needles that are 4 to 8 mm in length. If only longer needles are available, try injecting at an angle in order to avoid accidental injection into muscle. For those who are very lean (including young children), pinch up the skin when inserting/injecting the needle. Release the pinch after injecting, and if using a pen, keep the pen needle in for five to ten seconds to ensure complete insulin delivery.
If leakage occurs after the injection (appearance of insulin on the skin’s surface after removing the needle), consider leaving the needle in the skin longer or using a longer needle and injecting at an angle.
By the way, if the process of inserting the syringe, pen, or infusion set needle into your skin leaves you in a cold sweat, a number of injection aids are available. A list of such devices can be found in the Resources section in Chapter 10.
Factor 2: Other Diabetes Medications
Diabetes medications come in two forms: pills and injectables. Obviously, one of the injectables is insulin. But there are other injectables that can help to lower blood sugar, decrease appetite, and facilitate weight loss. We’ll get to these later in this chapter. For now, let’s explore the various oral medications.
Diabetes Pills
1. Pills that make you make more insulin
(only for type 2s, never for type 1s)
The original medications used to treat type 2 diabetes targeted the pancreas directly by increasing the production of insulin. This class of medications includes sulfonylureas (chlorpropamide, tolazamide, tolbutamide, glyburide, glipizide, and glimepiride) and meglitinides (repaglinide and nateglinide). Sulfonylureas work for twelve to twenty-four hours or more to lower blood sugar, whereas meglitinides work for only a few hours. Both sulfonylureas and meglitinides can cause hypoglycemia (low blood sugar) and weight gain.
Cut to the chase: Sulfonylureas and meglitinides are usually effective for lowering blood sugar levels in those who are in the very early stages of type 2 diabetes, before the pancreas has lost the ability to secrete sufficient amounts of insulin. However, by increasing the workload on the pancreas, these drugs may actually accelerate its breakdown. These drugs are of no practical use for people with type 1 diabetes or thos
e with type 2 who have progressed to the point of requiring insulin injections.
2. Pills that slow the liver’s sugar production
(mainly for type 2s, sometimes for type 1s)
The liver (the one in our bodies, not the one in the butcher’s shop) is a major source of sugar that appears in the bloodstream. In most people with type 2 diabetes and many with type 1, the liver oversecretes glucose, making blood sugars harder to control. Since being introduced in 1994, the biguanide drug metformin has become the most widely prescribed medication for diabetes and one of the most widely used drugs in the world. Metformin decreases the amount of sugar the liver produces. Secondary benefits may include improvement in cholesterol levels and insulin sensitivity. Metformin is often used in combination with other diabetes drugs, including insulin. However, people with kidney impairment should not use it, and those with liver problems must use it with caution.
Cut to the chase: Metformin is often a drug of first choice for those with type 2 diabetes, and it may be beneficial to those with type 1 who require unusually large doses of insulin. Because the liver is mainly responsible for causing blood sugar to rise overnight, metformin can be particularly helpful to those with elevated fasting glucose levels.
3. Insulin sensitizers (mostly for type 2s, rarely for type 1s)
Thiazoladinediones (TZDs), including pioglitazone and rosiglitazone, are medications that increase the sensitivity of the body’s muscle and fat cells to insulin. TZDs may be used in combination with other diabetes medications, including insulin. There is a risk of liver problems and fluid retention when using TZDs, so people with liver disease, poor heart function, or a history of congestive heart failure should not use them.
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