What is insulin?
Insulin is a hormone made by beta cells in the pancreas. Its main purpose is to help the body store the glucose that it gets from food. Without the presence of insulin, blood glucose can’t be effectively regulated. The body gains a significant amount of energy from glucose and a lack of control can have a significant impact on overall health.
Type 1 diabetes destroys the beta cells, which results in the body not being able to produce insulin naturally. People who have Type 1 diabetes are usually prescribed artificial insulin to replace what their body is lacking.
In contrast, people who have Type 2 diabetes can still produce insulin, but it isn’t enough for their body’s requirements. They may, therefore struggle to effectively use the insulin produced resulting in excess blood sugar building up in the body. Another problem resulting from this is that cells in the body do not receive the energy they need from glucose leaving a patient feeling fatigued.
Types of Insulin
There are four different types of insulin that are given in different ranges:
- Rapid Acting (Lispro) – This type of insulin reaches the blood within 15 minutes after injection. It peaks 30 to 90 minutes later and can last as long as 5 hours.
- Short Acting (Regular) – This type of insulin reaches the blood within 30 minutes after injection. It normally peaks 2 to 4 hours later and stays in the blood for around 4 to 8 hours.
- Intermediate Acting (NPH and Lente) – These insulins usually reach the blood 2 to 6 hours after injection. They can peak 4 to 14 hours later and stay in the blood for 14 to 20 hours.
- Long Acting (Ultralente) – This type of insulin takes 6 to 14 hours to start working. It has no peak or at least a small peak of 10 to 16 hours after injection and stays in the blood for 20 to 24 hours.
These ranges are based upon how soon the insulin starts to work (onset), when it will work the hardest (peak time) and how long it can last in the body (duration).
Some insulins can be mixed together. For example, you can buy Regular and NPH insulins pre-mixed in a bottle. It can be much easier to inject two types of insulin at a time. Nevertheless, the amount of one insulin can’t be adjusted without also changing how much you get of the other insulin.
It is important to know that each person will respond to insulin in their own way. The role of insulin depends on the type of diabetes.
People with Type 1 diabetes experience rising blood sugar levels if their insulin treatment is poorly managed or inconsistent, which then leads to acidosis. This condition is life threatening when left unchecked, therefore Type 1 diabetics are extremely reliant on insulin as an ongoing treatment.
Those with Type 2 diabetes will have a different experience with insulin. Although the body hasn’t destroyed its stores of insulin, there can be an increased resistance to the positive benefits of insulin.
Although administering insulin varies according to each individual, there are three different regimes that are most commonly used:
- Two Times Daily – Short and intermediate acting insulin should be taken before breakfast and evening meals. Short acting insulin provides stability throughout the morning and evening, whereas intermediate acting insulin ensures stability through the afternoon and overnight.
- Three Times Daily – Short and intermediate acting insulin should both be taken before breakfast. After this, short acting insulin should be administered before supper. Intermediate insulin is then taken before sleep so that the overnight period is covered.
- Multiple Daily – Short acting insulin is taken before meals. Intermediate or long acting insulin is administered before sleep which covers the overnight period.
How to Take Insulin
For many people who have diabetes, administering insulin can be a major lifestyle issue. Using injections can disrupt a daily routine, especially for teenagers and children. Insulin injections are generally administered through disposable insulin pens, or through ampoules that are designed for multiple use pens.
Injection remains the more favoured type of insulin administration. It allows more flexibility and is very similar to the natural processes that should be occurring in the body. Most people commonly use 8mm needles, yet 6mm and 12mm lengths are also available.
In some cases, people choose insulin pumps. They are attached to a patient at all times and feeds a constant insulin to the blood through a needle. Insulin pumps remain relatively uncommon in the UK. Furthermore, oral insulin is becoming a much more likely option, with some companies researching the possibilities of insulin that can be inhaled.
Administering too much insulin can lead to hypoglycemia. In the event of an overdose, you should immediately take enough fast-acting carbohydrate then seek advice from a healthcare professional.
Insulin sensitivity is the term used to describe how a person’s body responds to the effects of insulin. Someone who is insulin sensitive requires smaller amounts of insulin to reduce the levels of blood glucose in the body compared to someone who has low sensitivity i.e. insulin resistant.
Insulin sensitivity varies between people and doctors can test to establish how sensitive a person is to insulin.
Stress and illness can contribute towards short periods of reduced insulin sensitivity. In many cases, this should recover after the stress or illness has been dealt with.
High insulin sensitivity
Generally, having good sensitivity to insulin is an indication of good health, yet it can be a problem too.
Those who have a particularly high sensitivity to insulin can cause problems for people with Type 1 diabetes and especially for young children.
Having high insulin sensitivity can sometimes increase the risk of hypoglycaemia for those with Type 1 diabetes. For people who have high sensitivity there are insulin pens available that give half units to reduce the risk of a hypo.
Physical activity also poses an increased risk of hypoglycaemia by raising insulin sensitivity. Such effects can last for up to 48 hours after exercising, so knowing about the increased risk of hypos is important.
Low insulin sensitivity
People who have low insulin sensitivity are also referred to as insulin resistant. In these cases, individuals will require larger amounts of insulin to stabilise their blood glucose levels. Insulin resistance can indicate that the body is having problems with metabolising glucose which can be a sign of other health problems like high blood pressure and cholesterol levels.
Having low insulin sensitivity can cause the body to try and compensate by producing more insulin. High levels of circulating insulin (hyperinsulinemia) is commonly associated with damage to the blood vessels, high blood pressure, heart disease, heart failure, obesity, osteoporosis and cancer to certain extents.
When taking any kind of medication, there is usually a concern about side effects. Insulin side effects are very rare, but when such instances occur, allergic reactions can be severe and pose a significant risk to overall health.
Mild allergic reactions can include swelling, itching or redness around the injection site. Sustained nausea and vomiting are also signs of an allergy and consulting your GP is usually recommended.
Normally, insulins come dissolved in liquids at varying strength levels. Most people usually use U-100 insulin. this means that 100 units of insulin per millilitre of fluid. It is important to use a syringe that matches the insulin strength.
Storage and Safety
When storing and using insulin, there are some general rules to abide by:
- Using insulin that’s cold can make an injection more painful. Gently roll the insulin bottle between your hands to warm it up before use.
- Store any extra bottles of insulin in the fridge whilst they aren’t being used.
- Extreme temperatures destroy insulin, so don’t store bottles in places that are too hot or too cold.
- Similarly, never freeze insulin or store it in direct sunlight.
- If a bottle has been opened for more than 30 days, the potency of insulin can decrease.
- Observe the insulin the vial to check if it looks “normal”. For example, regular insulin should be clear, so any floating pieces or colour would be an indication that something is wrong.
- Never use insulin past the expiration date.