Insulin: What You Need to Know

After several months of reviewing the various types of diabetes medicines, we finally come to insulin. Insulin is both feared and revered. On the one hand, it’s a life-saving drug — people who have Type 1 diabetes depend on insulin to survive. But on the other hand, some people fight having to go on insulin tooth and nail. What is it about insulin that scares people off? Read on to find out more about one of the most important medical discoveries ever.

What is insulin?
Most people describe insulin as something that lowers blood sugar levels. In a nutshell, that’s correct. Insulin is a hormone (and a protein) that’s made in the beta cells of the pancreas. It works to move glucose from the bloodstream into the cells to be used for energy. Insulin also moves amino acids into cells to help make proteins, and it enhances fat storage, as well.


Who needs to take insulin?
Everyone needs insulin. The issue is whether someone makes enough of his own or needs to inject it. People who have Type 1 diabetes must inject (or inhale) insulin to stay alive. Many people with Type 2 diabetes must take insulin, as well, if their blood sugar and HbA1c goals aren’t met with diabetes pills or other injectables. Women who have gestational diabetes may also need insulin if they are unable to control blood sugar levels with meal planning.

How is insulin made?
Insulin was “discovered” in 1921 by two scientists, Banting and Best. Using an extract from the pancreases of dogs, these scientists successfully injected another dog (whose pancreas had been removed) and discovered that the dog’s blood sugar levels dropped. They gave the dog several injections of this extract every day, keeping it healthy and alive. The rest, as they say, is history.

Early types of insulin were made from the pancreases of cattle and pigs. The problem with beef and pork insulins, however, is that they were impure, causing many people to have allergic reactions and, over time, making the insulin less effective. In addition, it became costly to manufacture animal insulin.

In the 1970s, scientists began working on a process for making human proteins for purposes of research and to make medication. They discovered the human gene for making insulin, and in 1978, scientists from a company called Genentech were able to insert the insulin gene into E.coli, a type of bacteria, which then produced the protein (insulin). This process is called recombinant DNA technology.

Genentech then partnered with Eli Lilly and in 1982, the first engineered human insulin, called Humulin, was introduced to the market. Biologically engineered insulin is virtually identical to human insulin, unlike beef and pork insulin. In more recent years, insulin analogs have been introduced: these are made by tweaking the amino acid sequence of the insulin, causing it to work faster or slower than human insulin. This ability to manipulate engineered insulin allows people to take fast-acting insulin at mealtime, for example, and a longer-acting insulin at bedtime.

Why can’t insulin be taken as a pill?
This is a question that’s been asked time and time again. At this time, insulin must either be injected or inhaled. It’s not available in pill or capsule form. This is because insulin is a protein, and like all proteins, it is broken down by enzymes when it enters the digestive tract, which would make the insulin ineffective. We can keep hoping that the day will come, however, when you can swallow your insulin pill along with your daily multivitamin!

What’s meant by insulin “strengths”?
Insulin comes in different strengths, or concentrations. In the United States, insulin is available as “U-100,” meaning that there are 100 units of insulin per milliliter of fluid. Other strengths available are U-500, which may be prescribed for people with insulin resistance who require more than 200 units of insulin per day. U-500 insulin is five times stronger than U-100 insulin. A brand-new insulin was just introduced by Sanofi, called Toujeo. This is a U-300 insulin that’s a longer-acting form of insulin glargine.

Insulin available in other countries is often sold in a strength called U-40. If you inject insulin with a syringe, you must make certain to use syringes specifically for the particular strength that you’re using. Always bring plenty of insulin and syringes with you when you travel to other countries. If you run out of insulin and all that’s available is U-40, you must use a U-40 syringe, as well. All insulin pens are U-100.

More on insulin next week!

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  • abdo

    thanks for this article