Insulin: Function and types

Insulin is a hormone or chemical messenger that instructs cells to absorb glucose - a sugar - from blood. Glucose is essential for providing cells with the energy to function. Without it, or if there is a lack of its production in the body, it can lead to chronic conditions like diabetes.

The pancreas is responsible for producing insulin. More specifically, islets - a cluster of cells in the pancreas - are responsible for insulin production by measuring blood glucose levels. So higher glucose levels mean higher insulin production to balance sugar levels. The excess insulin is stored in the liver, fat and muscles.

Your glucose levels can drop if your body is stressed and needs an extra dose of energy. This is because the primary role of insulin in the body is to regulate its energy levels. It's also responsible for regulating fats and proteins and how the body metabolises carbohydrates.

The insulin hormone functions in the body in several ways and plays a part in its overall processes. Some of which include:

1. Modifies enzyme activity and the resulting reactions in the body.

2. Builds muscle during injury or sickness to repair muscular damage and increase its size and strength.

3. Regulates the uptake of amino acids, DNA replication and protein synthesis.

4. Manages triglyceride production by being absorbed into fat cells.

5. Manages protein and lipid breakdown according to the changes in those fat cells.

6. Responsible for the absorption of amino acids and potassium.

7. Manages sodium excretion and fluid volume in urine.

8. Enhances the brain's memory and learning capability.

9. Facilitates glucose as energy in cells through absorption.

10. Plays a part in stimulating glycogen production the in the liver.

Some people's immune systems can attack the islets responsible for insulin production. This can lead to the pancreas not producing enough insulin or not producing it at all. So cells would be unable to absorb the glucose in the bloodstream and can not convert it into energy.

A decreased or complete lack of insulin production leads to the onset of type 1 diabetes. The person will need regular shots of insulin to survive. A medical insurance plan that covers diabetes under its policy can be beneficial to cover the ongoing costs needed for regular insulin shots.

For others, especially those who are overweight, suffer from obesity or lead inactive lifestyles; their insulin is not effective at transporting glucose into their cells. This decreased effectiveness or inability of insulin’s role in the body is called insulin resistance.

People with insulin resistance are at risk of developing type 2 diabetes if their islets can not produce more insulin to overcome insulin resistance. Most health insurance plans cover type 1 and type 2 diabetes under their list of chronic conditions or long-term illnesses since it's a prevalent issue today.

Insulin can be taken in different types based on how long a person needs its effects to last in their body. It's categorised into different types based on factors such as:

- Speed Of Onset: How fast the effects of insulin can be felt once taken by the person.

- Peak: The speed at which the supplement (insulin) reaches its highest impact.

- Duration: The time it takes for the insulin to wear off.

- Concentration: The dosage per millilitre, where the standard concentration is 100 units per millilitre (U100).

- Mode Of Delivery: Whether the insulin needs to be injected into a vein, under the skin or through the lungs via inhalation, i.e. through pen, syringe, pump or inhaler.

The most common way people take insulin is by injecting it into the subcutaneous or fatty tissue near the skin's surface. These are the main types of insulin you would encounter.

- Fast-Acting Insulin

This type of insulin is injected into the subcutaneous tissue, where the body can readily absorb it through the bloodstream. Fast-acting insulin is used by patients with hypoglycemia and high blood sugar to control blood sugar spikes after eating.
There are two types of fast-acting insulin:

- Rapid-Acting Insulin Analogues: These take 5 to 15 minutes to take effect. However, its duration of effect relies on size and dosage. Most fast-acting insulin analogues last around 4 hours. Some examples are Aspart (Novolog) and Lispro (Humalog).

- Regular Human Insulin: Regular human insulin takes 30 minutes to an hour to take effect, with its effect lasting around 8 hours in the body. Larger doses can speed up the onset times but also delay the peak effect of regular human insulin. Some examples are Humulin R and Novolin R.

- Intermediate-Acting Insulin

Intermediate-acting insulin takes longer to take effect but lasts longer in the body. This type is the most effective at managing blood sugar levels overnight and between meals. Types of intermediate-acting insulin include:

- NPH human insulin: The onset for NPH is 1 to 2 hours, reaching its peak within 4 to 6 hours. In some cases, its effects can last up to 12 hours. Smaller doses can bring forward peak effects, and higher doses can delay the peak time and increase the duration of its effect. Some examples are Humulin N and Novolin N.

- Pre-mixed insulin: This is a mixture of fast-acting insulin and NPH. Its effects are a combination of NPH and fast-acting insulin. These mixtures can come in several concentration ratios like 50:50 to 75:25 or 70:30. A common example would be Novolog 70/30.

- Long-Acting Insulin

This type of insulin is slow to take effect and reach the bloodstream. It also has a low peak with a stabilising effect or "plateau" on the blood sugar levels, where it lasts most of the day. The most common example is Glargine (Lantus).

It's used primarily used overnight, between meals or during fasts.

Long-acting inulin has only one type under it: the long-acting analogue. These take 1.5 to 2 hours to take effect. Different brands have different duration, with most ranging between 12 to 24 hours.

Insulin is a vital hormone needed for the body to function and survive. It facilitates glucose absorption into cells for energy conversion, which is necessary to maintain a person's energy levels throughout the day. If your cells cannot absorb glucose from your bloodstream, it can lead to either type 1 or type 2 diabetes.

Both conditions require the person to take regular insulin shots to survive. If you have diabetes, having a health insurance plan can benefit you in the long run. Consider looking through the benefits of health insurance on Tata AIG's website if you're still on the fence about purchasing one for yourself.