Insulin can help people with diabetes manage blood sugar levels and avoid other issues. Senior Cardiac Nurse Christopher Allen talks to Dr Amanda Adler, Consultant Physician at the Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge who answers common questions about insulin.

Why do I need insulin?

Our bodies need glucose (a type of sugar) to function properly. Insulin, a hormone produced by the pancreas, helps move glucose from the bloodstream into your cells, giving them energy. In people who have diabetes, the pancreas produces very little or no insulin, so too much glucose stays in your bloodstream.

Diabetes is a long-term condition where there are high levels of glucose in the bloodstream. It can lead to serious complications like coronary heart disease or kidney failure.

People with type 1 diabetes are born with the condition (but age of diagnosis can vary) and will almost always need insulin, as their pancreas doesn’t produce any.

Type 2 diabetes develops over time, mostly due to lifestyle, and means the body is resistant to its own insulin. The average age of people developing the condition is dropping, mostly because more people are overweight at a younger age.

It’s important to keep blood glucose levels under control because long-term high levels can lead to eye damage and even limb amputation.

What else can help?

Lifestyle changes like eating a healthy, balanced diet and being physically active can help manage your risk and may delay or prevent the need for insulin. If you have type 2 diabetes, even a modest loss  of three per cent of body weight (for example, losing 2.4kg/5½lb if you weigh 80kg/12½st) can help control blood sugar.

Medications can also help. But, on average, people with type 2 diabetes require insulin within 10 years of diagnosis.

Where does prescribed insulin come from?

Historically, we used insulin from either cows or pigs, but this has become less and less common as medicine has advanced.

Most people are now given insulin that has been made in a lab by introducing a manmade human gene to bacteria or yeast, which multiplies to produce lots of insulin. It mimics the way real insulin is produced and used naturally in the body.

Can’t I just take a tablet?

Oral medications for type 2 diabetes can help, but if your blood glucose levels aren’t well controlled you’ll need insulin. As hard as scientists have worked, insulin pills have proven too delicate for stomach acid and wouldn’t survive the journey to your bloodstream.

How often will I need an injection?

Most people who need to take insulin will be asked to check their blood glucose levels first. You will use a finger-prick device (pictured above) to get a small drop of blood, which is then analysed on a glucose meter.

Insulin helps move glucose into your cells, giving them energy

Your brain and body need glucose for energy 24 hours a day, so people with type 1 diabetes take insulin with every meal. This is short-acting insulin, which helps control the rise in blood glucose levels after food.

Long-acting insulin is also needed to allow a steady release of glucose into your cells. It’s most commonly given at night when you usually aren’t eating and drinking.

Some formulations have both long- and short-acting insulin in them, reducing the number of injections you need. But it means you’ll need to keep your carbohydrate intake at a similar level every day, because you can’t alter the dose of insulin.

I’ve heard I might put on weight. Is this true?

Glucose is very high in calories (energy), so once insulin starts moving it from your bloodstream and into your cells, you will receive more calories than before, which can lead to weight gain.

Insulin is also an anabolic hormone, meaning it can naturally lead to weight gain and muscle growth. Some people without diabetes abuse it for bodybuilding purposes.

Healthy eating and keeping physically active will help you control your weight and have a positive effect on your blood glucose levels. This is especially true for those with type 2 diabetes, where lifestyle plays a significant role.

Are there any other risks?

Insulin decreases levels of glucose in the blood, and sometimes this level can become too low. This is called hypoglycaemia, and it’s important to be able to recognise the signs and symptoms (see box, below) so you can take quick action if it happens.

As a general rule, your blood glucose level shouldn’t be lower than 4mmol/L. Hypoglycaemia is a level of 3.5mmol/L or less, but taking early action can prevent it.

Can I still treat myself on special occasions?

It’s OK to splurge once in a while and eat more, or have more sugary or starchy foods than usual, but this shouldn’t be on a regular basis.

If you’re on long-acting insulin and medications, ensure you return to regular eating habits the next day. If you have short-acting insulin, you will be taught to adjust your insulin to a greater intake of food.

Symptoms of low blood sugar

If you are using insulin and your blood sugar goes too low, you may develop hypoglycaemia. Symptoms include:

  • sweating
  • dizziness
  • tiredness
  • blurred vision
  • trembling
  • shaking
  • paleness
  • palpitations
  • difficulty concentrating
  • confusion or disorientation

The immediate treatment for hypoglycaemia is to have some sugary, non-fatty food or drink (about 15–20g of rapidly acting carbohydrate) to end the attack. This could be a glass of fruit juice or soft drink, between three and five dextrose tablets or a handful of sweets.

You may be given a glucose gel or chewable tablet by your doctor to use should this occur.

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