Diabetes - Type 1 vs Type 2

Diabetes - type 1 vs type 2

Have you ever wondered what the difference is between type 1 and type 2 diabetes?

Both involve raised levels of glucose, or sugar, in the blood which if untreated can result in symptoms such as excessive thirst and urination, increased appetite, headache, irritability, fruity smelling breath, slow wound healing, blurred vision and fatigue. However the onset and causes of the two types are very different.

Type 1

Type 1 is the rarer of the two and constitutes only around 10% of diabetics. It is an autoimmune condition where the body produces antibodies which destroy the cells in the pancreas responsible for producing insulin. Without insulin, our cells cannot take up glucose and its levels build up in the blood. Symptoms can occur quite suddenly, sometimes only over a matter of weeks.  Although it is often associated with a diagnosis in childhood or early adulthood, type 1 diabetes can be diagnosed at any age, potentially leading to difficulties distinguishing between the two types in older adults. Blood tests are used to diagnose diabetes and can either measure blood glucose levels after fasting, or HbA1c levels which indicate the average concentration of blood glucose over the preceding 3 months. 


Type 1 diabetes is treated with injections of insulin. Testing of current blood glucose levels is key and influences the calculation of the dosage and timing of insulin injection. Other key factors are any planned physical activity which can mitigate blood sugar spikes, and food intake since carbohydrates will increase blood sugar levels more than proteins or fats. Accuracy is important to avoid too much insulin as this can cause dangerously low blood sugar levels.


 As with other autoimmune diseases, it is not clear what causes type 1 diabetes, but immune and genetic factors play a role, as well as environmental triggers such as viruses. There is also an increased risk of developing other autoimmune diseases, in particular coeliac or autoimmune thyroid disease.

Type 2

Around 90% of diabetics have type 2 diabetes which is often associated with lifestyle and excess weight, especially extra fat in the central abdominal area. It is usually diagnosed in adults and develops gradually, often with no symptoms until a more advanced stage is reached, however more younger people are now being diagnosed with type 2 due to the increased numbers of young people with obesity. 
In type 2 diabetes there is not only a difficulty producing insulin in the pancreas, but also insulin resistance in the cells which hinders cells taking up glucose from the blood even in the presence of insulin. Both result in high blood glucose levels.


Lifestyle factors such as a lack of physical activity, being obese and an unhealthy diet are linked with type 2 diabetes. In particular a high carbohydrate and high fat diet, typical in modern Western societies, causes high levels of glucose and fats in the blood, which leads to increased production of harmful free radicals, chronic low grade inflammation, damage to the mitochondria of cells, and in turn contributes to insulin resistance. Similarly, a sedentary lifestyle is considered inflammatory and a contributing factor. 


Metformin is a medication which reduces the amount of glucose released by the liver and improves how the body uses insulin and is sometimes prescribed for type 2 diabetes. Insulin injections are also prescribed to provide the cells with sufficient insulin. The good thing is that diet and lifestyle interventions can prevent pre-diabetes developing into type 2 diabetes and once the disease has begun, there are things you can do to help manage it and even put it into remission, not everyone needs medication or insulin!
Weight loss is a great way to reduce insulin resistance and exercise has also been shown to reduce inflammation, encourage the production of antioxidants to counter harmful free radicals and improve glucose tolerance. A low refined and low starchy carbohydrate diet can also support management of type 2 diabetes and help with weight loss. Additionally there are benefits in reducing saturated and trans fats from meat, fried foods and processed baked goods and getting your fats instead from healthier options like olive oil, oily fish, nuts and seeds. Every body is different and it is essential to monitor blood sugar levels and individual responses.

The microbiome???

Diabetes is complex and studies are now starting to show that the immune system and gastrointestinal microbiome also play a role in the development of both type 1 and type 2 diabetes. The microbiome is the bacteria living in our gut which ferments dietary fibre and produces beneficial by-products called short chain fatty acids (SCFAs). If the balance of friendly and pathogenic bacteria is disrupted, known as dysbiosis, SCFA production is reduced. This can have negative impacts on the gut lining and immune system as well as the production of insulin producing cells in the pancreas. However more studies are needed to fully understand the influence of the microbiome, it is a fascinating and growing area of research. 
Remember that this beneficial dietary fibre comes from complex carbohydrates, meaning you need to choose varieties with a high fibre content, lower sugar and starch content like pulses, green vegetables, carrots, cauliflower, salad leaves, mushrooms,  onions, peppers and whole fresh or frozen fruit.


DiMeglio, L.A., Evans-Molina, C., Oram, R.A., 2018. Type 1 diabetes. 
Galicia-Garcia, U. et al., 2020. Pathophysiology of Type 2 Diabetes Mellitus.