Diabetes mellitus, commonly known as diabetes, is a prevalent chronic condition affecting millions worldwide. At its core, diabetes disrupts the body’s ability to regulate blood glucose levels, leading to a state of hyperglycemia (high blood sugar). Understanding What Does Insulin Do is crucial to grasping the complexities of diabetes and its management. Insulin, a hormone produced by the pancreas, plays a central role in this process. This article delves into the essential functions of insulin, its different types, and its critical importance in managing diabetes.
Diabetes, if left unmanaged, can lead to severe health complications, including damage to the eyes, kidneys, nerves, heart disease, and stroke. In Australia alone, hundreds of people are diagnosed with diabetes every day, making it the country’s fastest-growing chronic condition. The primary types of diabetes are type 1, type 2, and gestational diabetes, each with distinct underlying mechanisms but all linked to the role and effectiveness of insulin.
Type 1 Diabetes: When the Body Stops Producing Insulin
Type 1 diabetes is characterized by the pancreas’s inability to produce insulin. This occurs when the immune system mistakenly attacks and destroys the insulin-producing beta cells in the pancreas. Without insulin, glucose cannot enter cells to be used for energy. Instead, it accumulates in the bloodstream, resulting in hyperglycemia. What does insulin do in a healthy individual? It acts as a key, unlocking cells to allow glucose to enter and fuel them. In type 1 diabetes, this key is missing.
This form of diabetes typically manifests in childhood or adolescence but can occur at any age. It is not linked to lifestyle factors but is believed to be triggered by environmental factors in genetically predisposed individuals. Individuals with type 1 diabetes require lifelong insulin therapy, usually through injections, to survive.
Type 2 Diabetes: Insulin Resistance and Insufficient Production
Type 2 diabetes, the most common form of diabetes, accounting for 85 to 90% of cases, develops when the body becomes resistant to insulin, and the pancreas may not produce enough insulin to overcome this resistance. What does insulin do in type 2 diabetes? While insulin is still produced, its effectiveness is reduced, and the body’s cells do not respond to it properly. This condition, known as insulin resistance, leads to a gradual rise in blood glucose levels.
Often linked to lifestyle factors such as being overweight and physical inactivity, type 2 diabetes also has a strong genetic component. Certain ethnic groups are at higher risk. Initially, type 2 diabetes can often be managed through lifestyle modifications like a healthy diet and increased physical activity. However, many individuals eventually require oral medications and, in some cases, insulin injections to maintain healthy blood glucose levels. Around half of people with type 2 diabetes may need insulin injections within 6 to 10 years of diagnosis.
Gestational Diabetes: Diabetes During Pregnancy
Gestational diabetes develops during pregnancy and usually resolves after childbirth. It affects 5 to 10% of pregnant women. During pregnancy, hormonal changes can lead to insulin resistance. What does insulin do in gestational diabetes? The body may not be able to produce enough insulin to overcome this resistance, leading to elevated blood glucose levels.
Management typically involves dietary adjustments, regular exercise, and blood glucose monitoring. Some women may require insulin injections during pregnancy to manage their blood glucose levels and ensure a healthy pregnancy and delivery. Women with gestational diabetes have an increased risk of developing type 2 diabetes later in life.
Insulin’s Crucial Role: Moving Glucose into Cells
What does insulin do fundamentally? Insulin is a hormone produced by the beta cells in the pancreas, and its primary function is to regulate blood glucose levels. After we eat, carbohydrates are broken down into glucose, which enters the bloodstream. Insulin acts as a messenger, signaling cells throughout the body, including muscle, liver, and fat cells, to absorb glucose from the bloodstream.
In simple terms, insulin facilitates the uptake of glucose by cells, where it is used for energy production. By moving glucose out of the bloodstream and into cells, insulin lowers blood glucose levels back to the normal range. When insulin is deficient or ineffective, as in diabetes, glucose remains in the blood, leading to hyperglycemia and its associated complications.
Types of Insulin: Different Actions and Durations
For individuals with diabetes who require insulin therapy, various types of insulin are available, categorized by how quickly they start working (onset), when they are most effective (peak time), and how long they last (duration). Understanding these differences is vital for effective diabetes management.
The main types of insulin include:
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Rapid-acting insulin: Begins working within 2.5 to 20 minutes, peaks in 1-3 hours, and lasts for up to 5 hours. It’s designed to cover mealtime glucose spikes and is taken immediately or shortly before eating. Examples include insulin aspart, insulin lispro, and insulin glulisine.
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Short-acting insulin: Starts working within 30 minutes, peaks in 2-5 hours, and lasts for 6-8 hours. It is also used for mealtime coverage but needs to be injected 30 minutes before eating. Examples include Actrapid® and Humulin® R.
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Intermediate-acting insulin: Starts working in 60-90 minutes, peaks in 4-12 hours, and lasts for 16-24 hours. Often referred to as basal insulin, it provides background insulin coverage for longer periods. Examples include Humulin® NPH and Protaphane®.
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Long-acting insulin: Provides a slow, steady release of insulin with minimal peak action and can last up to 24 hours or more. These insulins offer basal coverage with once- or twice-daily injections. Examples include insulin glargine (Lantus®, Toujeo®) and insulin detemir (Levemir®).
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Mixed insulin: Pre-mixed combinations of rapid- or short-acting insulin with intermediate-acting insulin. These offer convenience by providing both mealtime and basal coverage in a single injection. Examples include NovoMix® 30, Humalog® Mix 25/50, Mixtard® 30/70/50/50, and Humulin® 30/70.
The choice of insulin type and regimen is individualized and determined by a healthcare professional based on the person’s specific needs, lifestyle, and blood glucose patterns.
Insulin Delivery Devices: Syringes, Pens, and Pumps
Insulin can be administered using different devices:
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Insulin syringes: Traditional method, available in various sizes to match insulin doses. Syringes are single-use and require manual drawing of insulin from a vial. While still used, insulin pens are more common now due to their convenience.
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Insulin pens: Pre-filled or reusable devices that contain insulin cartridges. They offer more convenience and ease of use compared to syringes. Doses are dialed in, and insulin is injected through a fine needle. Disposable pens are discarded when empty, while reusable pens require cartridge replacement. Pen needles are single-use and come in various lengths and gauges.
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Insulin pumps: Small, programmable devices worn externally that deliver rapid-acting insulin continuously through a thin tube (infusion set) inserted under the skin. Pumps mimic the pancreas’s function by providing a basal rate of insulin and bolus doses at mealtimes. Insulin pumps are not suitable for everyone and require careful management and training.
The selection of an insulin delivery device depends on individual preferences, insulin regimen, and healthcare provider recommendations.
Insulin Injection Sites and Absorption
Insulin is injected into the subcutaneous tissue (fatty layer under the skin), not into muscle or directly into the bloodstream. What does insulin do after injection? It is absorbed into the bloodstream at varying rates depending on the injection site.
The abdomen offers the fastest insulin absorption and is the most common injection site. Upper arms, buttocks, and thighs have slower absorption rates. Rotating injection sites within the same area is recommended to prevent lipohypertrophy (lumpy or scarred tissue) and ensure consistent absorption.
Factors that can speed up insulin absorption include injecting into an exercised area, heat (hot showers, baths), and massaging the injection site. Factors that can delay absorption include injecting into lipohypertrophy areas, cold insulin, and smoking.
Safe Insulin Storage and Handling
Proper insulin storage is crucial to maintain its effectiveness. Unopened insulin should be stored in the refrigerator (2-8°C) and kept on its side. Opened insulin can be stored at room temperature (below 25°C) for up to one month. Insulin should never be frozen or exposed to extreme temperatures or direct sunlight, as this can damage it.
Always check insulin for any changes in appearance (cloudiness in clear insulin, lumps in cloudy insulin) or if it has expired. Used syringes, pen needles, and lancets must be disposed of safely in sharps containers.
Managing Diabetes with Insulin: A Collaborative Effort
Understanding what does insulin do is fundamental for individuals with diabetes, especially those requiring insulin therapy. Effective diabetes management involves a collaborative effort between the individual, their healthcare team (doctors, diabetes nurse educators, dietitians), and ongoing education and support.
Starting insulin therapy can be daunting, but with proper education and support, it becomes manageable. Healthcare professionals provide guidance on insulin types, injection techniques, dosage adjustments, blood glucose monitoring, and managing hypoglycemia (low blood sugar). Regular blood glucose monitoring and record-keeping are essential for adjusting insulin doses and optimizing blood glucose control.
Insulin doses may need to be adjusted over time due to various factors, such as changes in diet, exercise, illness, and weight. Therefore, regular follow-up with the diabetes healthcare team is vital. For individuals with type 1 diabetes, carbohydrate counting and matching insulin doses to food intake is a key aspect of management.
Seeking Help and Support
Living with diabetes and managing insulin requires ongoing support and resources. Numerous healthcare professionals and organizations are available to provide assistance:
- General Practitioners (GPs)
- Diabetes Nurse Educators
- Dietitians
- Local Community Health Services
- National Diabetes Services Scheme (NDSS)
- Diabetes Australia and state-based diabetes organizations
- Baker Heart and Diabetes Institute
These resources offer education, support, and guidance to help individuals effectively manage their diabetes and live healthy lives.
In conclusion, what does insulin do is essential for life. It is a vital hormone that regulates blood glucose levels by enabling glucose uptake into cells for energy. In diabetes, insulin’s role is disrupted, leading to hyperglycemia and its complications. Understanding insulin’s function, types, and proper use is paramount for effective diabetes management and maintaining overall health and well-being.
