Understanding Insulin

Diabetes is a common illness, so most of us, whether we know someone with diabetes or not, have heard of Insulin. But what is it? How does it work? And how does it help control diabetes?

Natural Insulin
Insulin is a hormone that occurs naturally in the body. When food is ingested, the carbohydrates are broken down into Blood glucose, which is where the body gets most of its energy. The Pancreas makes and releases insulin to help the body use or store that blood glucose. Insulin works with other hormones, amylin and Glucagon, to do its job.

Insulin and Diabetes
In people with type 1 diabetes, the pancreas fails to make insulin. In type 2 diabetes, the body makes it, but doesn’t use it properly. Why does this matter? Consistently high levels of blood glucose can cause all kinds of damage to the body:
  • It assists the forming of blockages of the arteries to the heart, brain, and legs (and the rest of the body)
  • Damage to nerves, causing numbness and tingling (usually starting in the hands and feet)
  • Damage to organs, increasing the risk of blindness, stroke, kidney failure, heart attack, and lower extremity amputation
Those with type 1 diabetes must add insulin to their bodies to properly handle the blood glucose from their food. It can’t be ingested (such as taken in pill form) because it would be digested along with everything else, and destroyed by the stomach acid. It must be injected or it won’t get into the bloodstream.

Each patient is unique, and the factors governing the disease and the patient’s lifestyle affect how they are treated. Insulin comes in many types—more than 30 available, differing in how they are made, how they work, and how much they cost. Some comes from pigs, and some is manufactured (synthetic) to match human insulin.

Types of Insulin
The types of insulin used to treat diabetes include:
  • Rapid-acting insulin, which starts to work within five minutes. It peaks in an hour, and wears off the soonest. The injection would be given at the same time as a meal, and is usually used in conjunction with long-acting insulin.
  • Short-acting, also known as regular insulin. This takes 30 minutes to take effect, and can be taken in advance of a meal. It continues to control blood glucose for a little longer than rapid-acting.
  • Intermediate-acting, also often used with rapid- or short-acting to take care of insulin needs over a longer period, usually about half a day.
  • Long-acting insulin is usually taken in the morning and balances blood glucose levels for a full day, used with rapid- or short-acting insulin.
  • Pre-mixed insulin mixes short-acting and intermediate-acting insulin and is usually taken twice a day, just before meals, and is used mainly for people who have difficulty mixing their own insulin and reading instructions/dosages, etc.
What kind of insulin each patient uses depends on many factors.
How the body responds to insulin is different from person to person. What you eat and drink and when, as well as your exercise and activity levels, are factors to consider. The number of injections a person can give themselves, how often they can check their blood glucose levels, how old they are, and their blood glucose management goals all contribute to the decision of what ind(s) of insulin to use and how.

Structure and Source
All insulins are introduced into the body in liquids in which they’ve been suspended or dissolved. It can come in different strengths, though the most common strength is U-100 (100 units of insulin per milliliter of fluid).

Additives are put into the solution to keep bacteria from growing and keep a neutral balance between acids and bases. As with anything, allergic reactions to the additives can occur, though they are rare.

All insulin in the United States is now manufactured based on human insulin. Synthetic insulin was first produced in the 1980s and has completely replaced the old sources, animal insulin (primarily from the pancreases of cows and pigs). This has been a tremendous benefit. However, some people react and respond better to animal insulin. Because of this, the FDA allows the import of animal insulin for individuals.

How to Take Insulin
Your doctor will work with you to find the optimal routine for your body and your specific illness. Generally speaking, a type 1 diabetic starts with two injections a day of two different types of insulin with a goal of eventually taking three or four injections a day of a combination of types. It is believed that three or four injections a day will provide the best management of blood glucose and delay or prevent the long-term problems with nerve, eye, and kidney damage that diabetes can cause.

There are three ways to deliver insulin: a syringe, a pen, or a pump.

The Syringe
Newer syringes, or needles, are thinner and shorter than the older ones, which makes the injection less painful. The needle is inserted just under the skin, into the fatty tissue in either the thigh, buttocks, abdomen, or upper arm.

The Pen
An insulin pen either comes filled with the insulin and uses a dial to select the dose, or a cartridge is inserted into the pen. The insulin is injected through a needle just like a syringe, but uses a trigger instead of a pushing action. These are easier for kids to use to self-administer their insulin, and are more convenient than a syringe/bottle combination.

The Pump
A small unit is worn on the outside of the body. Instead of using needles, insulin is delivered at regular intervals through a tube into a Catheter inserted under the abdomen’s skin. The main advantage to the pump is that it can keep the blood glucose levels more constant, and reduces or eliminates the need for individual injections.

New Methods
Using a needle several times a day becomes routine, but isn’t exactly fun. Research is always being conducted into new ways to introduce insulin. For a time, an inhaled version was being produced, but the manufacturer halted sales in 2007. Someday, maybe we’ll have mouth sprays or skin patches. In the meantime, the syringe, pen, and pump are the available methods of delivery.

Where to Inject
Insulin can be injected into the abdomen for the fastest delivery, the upper arm (a little more slowly), or the thigh or buttocks (slowest delivery). Consistency is important for management, so using the same general area for certain meals is best. You should vary the needle site for each shot to avoid creating hard lumps or fatty deposits. This means moving around each area.

Monitoring
The counterpart to insulin use is monitoring. What you eat, when you eat, how you exercise and when, big events or excitement, medication, and illness can all affect blood glucose levels. And the same things might have different results at different times. This means that finger pricks to test blood glucose levels several times a day are essential.

Type 1 diabetes is a lifelong condition requiring equally lifelong care. Understanding every aspect of the disease will make monitoring and treatment easier to handle, for children and adults alike.