Why Blood Sugar Matters: Understanding Diabetes

In 2024, approximately 589 million adults had diabetes across the globe—that’s 1 in 9 adults (aged 20 to 79) across the world who are living with diabetes (International Diabetes Federation, 2025). Out of these numbers, more than 4 out of 10 diabetic people are unaware they are diabetic.

Diabetes is much more prevalent than most people realise. But what actually is it, and how does it affect the lives of those who have it?

Blood glucose regulation: insulin and glucagon 

But first, in order to properly understand how type 2 diabetes affects the body, we need to know how blood sugar levels are controlled.

Blood glucose simply means the amount of glucose circulating in your bloodstream. In people unaffected by diabetes, there are two hormones mainly responsible for the regulation of blood glucose levels. 

1. Insulin increases cells’ uptake of sugar from the blood and triggers glucose to be converted to glycogen and stored in liver cells, lowering blood glucose levels. 

   1. In essence, insulin facilitates the passage of glucose through the cell membrane with greater ease and efficiency. While cells can still absorb glucose without it, insulin makes it a lot faster.

   2. Fun fact—how insulin works: insulin stimulates an increase in protein channels in the plasma membrane, allowing large glucose molecules to diffuse into cells more easily. CLICK HERE if you want to learn more about facilitated diffusion.
      

2. Glucagon triggers the liver to break down glycogen into glucose, which is released into the bloodstream, increasing sugar levels. 

   1. Glucose is stored in the body as the complex molecule glycogen. Glycogen is unusable until broken down into glucose as fuel for the body, and does not affect blood glucose levels.

   2. Located in the pancreas, in the Islet of Langerhans, insulin is produced by beta cells, while glucagon is produced by alpha cells.

Fig 1: Diagram of insulin and glucagon's role in the regulation of blood glucose

What is the difference between type 1 and type 2 diabetes?

Type 1 diabetes is an autoimmune disorder, influenced by genetic factors, where the body’s immune system attacks and kills insulin-producing cells in the pancreas, impairing the body’s ability to regulate blood glucose levels. Type 1 diabetes is also known as juvenile diabetes (as it is commonly diagnosed in youths) or insulin-dependent diabetes (as the body produces little to no insulin).

Because type 2 diabetes is generally caused by unhealthy lifestyle factors and appears in older ages, it is much more common than type 1 diabetes. In type 2 diabetes, cells start developing a resistance to insulin. This stimulates the pancreas to produce higher amounts of insulin, leading cells to become even more resistant, creating a harmful feedback loop. Furthermore, the abnormally high levels of insulin secreted by the pancreas over long periods of time cause its cells to wear out and die.

How does diabetes affect the everyday lives of people?

Normally, your body uses insulin and glucagon every day to carefully manage the amounts of sugar in your blood. After eating a meal, nutrients (including sugars) in the small intestine are absorbed into the bloodstream, increasing blood sugar, and your body releases insulin to bring blood glucose to normal levels. During physical activity, cells use up glucose like fuel to produce energy via cellular respiration, causing blood glucose to decrease. The pancreas then releases glucagon to replenish your blood glucose levels. 

Diabetic people are unable to properly manage their sugar levels because of a resistance to or lack of insulin. As a result, blood glucose levels tend to rocket up when sugary or carbohydrates-heavy foods are consumed, and take longer than usual to recede down to normal levels again.

Fig 2: Graph depicting blood glucose levels of a normal, pre-diabetic, and diabetic person

Notice how the green line representing the blood glucose of a diabetic person rises sharply, and takes a significant amount of time to return to normal, compared to a non-diabetic person. This is because there is a lack of effective insulin to increase the rate at which glucose is removed from the blood.

Generally, with a functional Islet of Langerhans, regardless of whether you are male or female, doing physical exercise or relaxing, eating or not eating, it is this careful regulation that keeps the glucose levels within a narrow range of 4.0 to 7.8 millimoles of glucose per litre of blood (mmols/L). 

Regulation of blood glucose levels is important because too high or too low amounts of sugar in our blood impact the body’s functioning.

Short-term effects of too high blood sugar (hyperglycemia) include:

• Headaches

• Fatigue

• Blurred vision

• Increased thirst and urination.

 Long-term effects become more severe with:

• Increased risk of cardiovascular disease, kidney damage, and nerve damage.

• Slower wound healing 

• Vision problems.

Long-term hyperglycemia increases the likelihood of fatty deposits in your veins, which can increase blood pressure and damage the vessels. This especially impacts the thin and delicate vessels in the eyes, causing vision damage, and puts more strain on the heart.

Terminology tips:

• ‘Hyper’ as a prefix means over, above, or excessive.

• ‘Hypo’ as a prefix means below, less than normal, or deficient. 

Treatments for Diabetes

While both type 1 and type 2 diabetes cannot be cured, the quality of life for individuals can be treated and improved through blood glucose monitoring, insulin therapy, and a healthy lifestyle with exercise. 

For type 1 diabetes, research is being done for stem cell therapy and islet cell transplantation, where healthy insulin-secreting cells are transplanted into an affected individual. 

Fun Facts

• Diabetes is the shortened name of ‘Diabetes Mellitus’

• Animals are able to regenerate parts of their pancreas more effectively than humans (Zhou and Melton, 2018).

• The regulation of blood glucose is a negative feedback loop. This means that when too high blood sugar is detected by receptors, the body triggers a series of actions that counteract the stimulus and bring the body back to homeostasis.

Conclusion

Diabetes is more than just high blood sugar—it is the disruption of the careful cycle between insulin and glucagon. When not enough insulin is produced, or the body develops a resistance to it, blood glucose cannot be regulated, and this affects millions of people across the world. Understanding this careful process is the first step to better support diabetic individuals.

Reference List

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