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Prediabetes is often treated like a warning light: your blood sugar is higher than normal, but not yet high enough to be called diabetes.
But prediabetes is not simply “almost diabetes.” It reflects underlying changes in how the body responds to insulin, handles glucose, and regulates metabolism. These changes can develop gradually, sometimes years before type 2 diabetes is diagnosed. And even before blood sugar reaches the diabetic range, prediabetes can begin affecting tissues throughout the body, including the blood vessels.
So what exactly is happening when someone develops prediabetes, and what can you do about it?
Let's take a closer look.
How the Body Regulates Blood Glucose
Our blood glucose levels are tightly regulated.
After we eat, carbohydrates are broken down into glucose and absorbed into the bloodstream. Blood glucose naturally rises, prompting the pancreas to release insulin, which helps move glucose into tissues such as muscle, where it can be used for energy.
What we eat can influence how quickly and how much blood glucose rises. An apple and a candy bar both contain sugar, but the apple also contains fiber and intact plant structures, which slow digestion and glucose absorption.
So, Are Glucose Spikes Bad?
A temporary rise in blood glucose after a meal is normal. The concern is when the body has difficulty bringing glucose back down or when elevated glucose becomes frequent or prolonged.
Repeated exposure to elevated glucose can increase oxidative stress and glycation, which can damage cells and interfere with normal vascular function.
When Blood Glucose Regulation Starts to Break Down
The increase in blood glucose is usually a sign of a larger problem: insulin resistance.
When tissues become less responsive to insulin, the pancreas initially compensates by producing more. This can keep blood glucose relatively normal even while insulin resistance is developing.
Eventually, the pancreas may no longer be able to compensate. Blood glucose rises further, and prediabetes can progress to type 2 diabetes.
Progression is not inevitable. Some people return to normal glucose regulation, while others progress to diabetes. Risk depends on factors including the degree of glucose impairment and overall metabolic health.
What happens to insulin when insulin resistance begins to develop?
How Does Prediabetes Develop?
Insulin resistance is usually influenced by multiple factors, including genetics, physical activity, body composition, diet, and other metabolic factors.
Excess visceral fat can promote inflammation and insulin resistance. As insulin resistance develops, elevated glucose, fatty acids, and inflammatory signals can also increase oxidative stress and chronic low-grade inflammation.
This creates a cycle:
Insulin resistance → higher insulin production → metabolic stress → rising blood glucose → greater insulin resistance
Prediabetes and Your Blood Vessels
Your blood vessels are not simply pipes carrying blood around the body. Their inner lining, called the endothelium, responds to hormones, nutrients, and blood flow.
Insulin is one of those signals.
Normally, insulin stimulates endothelial cells to produce nitric oxide (NO), helping blood vessels relax and increasing blood flow. This also helps deliver insulin and glucose to tissues.
In prediabetes, this system can become less responsive. Impaired microvascular function can limit the delivery of insulin and glucose to tissues, meaning the blood vessels themselves can become part of the insulin resistance problem.
And what about angiogenesis?
Diabetes can also disrupt angiogenesis, the formation of new blood vessels.
In the retina, excessive angiogenesis can occur. Chronic high glucose can promote oxidative stress, inflammation, and VEGF signaling, driving the growth of fragile vessels that can leak or bleed and threaten vision.
In wounds, the problem can be the opposite. Impaired endothelial responses and disrupted VEGF signaling can limit the formation of new blood vessels needed to deliver oxygen and nutrients, contributing to chronic diabetic foot ulcers. Severe ulcers can progress to tissue loss and contribute to diabetes-related lower-limb amputations.
What Can You Do About Prediabetes?
The good news is that prediabetes is a modifiable stage. Lifestyle changes can improve insulin sensitivity and reduce the likelihood of progression to type 2 diabetes.
🚶 Move regularly
Physical activity helps muscles take up glucose and improves insulin sensitivity. In the Diabetes Prevention Program, an intensive lifestyle intervention reduced the development of type 2 diabetes by 58% over about 3 years.
Your muscles are one of the body's largest sites for glucose disposal, so regularly using them changes how your body handles glucose.
🥗 Focus on dietary quality
Rather than eliminating one specific food, focus on a dietary pattern built around fiber-rich foods, minimally processed foods, and sources of unsaturated fats, while limiting excess saturated fat and highly refined foods.
Fiber-rich foods: Add beans, lentils, oats, berries, vegetables, or whole grains to meals.
Minimally processed foods: Choose foods like fresh or frozen vegetables, fruit, whole grains, beans, eggs, fish, and plain yogurt more often than highly processed packaged foods.
Unsaturated fats: Use olive oil, avocado, nuts, seeds, and fatty fish such as salmon in place of butter or foods high in saturated fat.
Limit excess saturated fat: Choose fish, beans, poultry, or plant-based proteins more often than fatty cuts of meat, butter, or full-fat processed meats.
Limit highly refined foods: Swap refined grains and sugary foods, such as white bread, pastries, and sugary cereals, for whole grains, fruit, or higher-fiber options.
⚖️ Weight loss can help, when appropriate
For people with prediabetes and overweight or obesity, weight loss can improve insulin sensitivity, inflammation, blood pressure, and lipid levels. But the metabolic benefits of lifestyle changes extend beyond the number on the scale.
Don't wait for diabetes
Prediabetes isn't a guarantee that diabetes is coming. It's a signal that the body's metabolic system is under strain, and an opportunity to intervene before more extensive damage occurs.
Don’t miss this Fiber-packed lentil soup! Made with lentils, whole grains, and plenty of vegetables, it’s a delicious way to build a balanced meal and support healthy blood sugar levels.
Check out this weeks youtube video to see our mascot Dr. Angio bringing complex health and research topics to life.
Best wishes,
- The Angiogenesis Foundation
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