Comprehensive Diabetes Knowledge

What Is Diabetes?

Diabetes is a chronic metabolic disease characterized by persistently elevated blood glucose levels. According to the American Diabetes Association (ADA), diabetes occurs when the pancreas cannot produce enough insulin or when the body responds poorly to the insulin produced. Insulin is a hormone secreted by pancreatic beta cells, acting like a “key” that helps glucose from the blood enter cells to provide energy for the body.

Diabetes is mainly divided into four types: type 1 diabetes, type 2 diabetes, gestational diabetes, and other specific types. Type 1 diabetes typically occurs in children and adolescents, resulting from the immune system mistakenly attacking and destroying pancreatic beta cells, causing complete inability to secrete insulin. Type 2 diabetes is the most common type, accounting for over 90% of all diabetes cases, primarily related to insulin resistance and relative insulin secretion insufficiency. Gestational diabetes is blood glucose abnormality first detected during pregnancy, usually returning to normal after delivery but increasing the risk of developing type 2 diabetes in the future.

Typical symptoms of diabetes include polyuria (frequent urination), polydipsia (excessive thirst), polyphagia (increased appetite), and weight loss. These symptoms result from osmotic diuresis caused by high blood glucose, causing the body to lose excessive water. However, many type 2 diabetes patients have no symptoms in early stages, making regular screening particularly important. If blood glucose remains elevated for a long time, it can cause damage to multiple organs in the body, including the heart, blood vessels, eyes, kidneys, and nervous system.

Importance of Blood Glucose Monitoring

Diagnostic Criteria for Diabetes

The ADA has clarified diagnostic criteria for diabetes—any of the following qualifies as diabetes diagnosis: fasting plasma glucose (FPG) ≥126 mg/dL (7.0 mmol/L); or 2-hour plasma glucose ≥200 mg/dL (11.1 mmol/L) during oral glucose tolerance testing (OGTT); or hemoglobin A1c (HbA1c) ≥6.5% (48 mmol/mol); or in a patient with classic hyperglycemic symptoms, random plasma glucose ≥200 mg/dL (11.1 mmol/L).

Prediabetes diagnostic criteria include: impaired fasting glucose (IFG): fasting glucose 100-125 mg/dL (5.6-6.9 mmol/L); or impaired glucose tolerance (IGT): 2-hour glucose 140-199 mg/dL (7.8-11.0 mmol/mol) during OGTT; or HbA1c 5.7%-6.4% (39-46 mmol/mol).

It is important to note that a single blood glucose test result cannot directly diagnose diabetes—repeat testing on another day is needed for confirmation. For HbA1c testing, if results are inconsistent with clinical judgment, confirmation using an alternative testing method is recommended.

Blood Glucose Control Targets

For most diabetes patients, ADA-recommended blood glucose control targets are: HbA1c below 7% (53 mmol/mol); fasting blood glucose 80-130 mg/dL (4.4-7.2 mmol/L); 2-hour postprandial glucose below 180 mg/dL (10.0 mmol/L). These targets are general recommendations—specific targets should be individualized based on factors such as patient’s age, disease duration, life expectancy, comorbidities, and hypoglycemia risk.

For patients with shorter disease duration, long life expectancy, few complications, and low hypoglycemia risk, stricter control targets can be used, such as HbA1c below 6.5% (48 mmol/mol). Conversely, for elderly patients, those with long disease duration, serious comorbidities, or high hypoglycemia risk, relatively looser control targets should be adopted, such as HbA1c below 8% (64 mmol/mol).

In addition to blood glucose control, the ADA also emphasizes comprehensive management of cardiovascular risk factors, including blood pressure and lipid management. Blood pressure control targets for diabetes patients are generally below 130/80 mmHg. For lipid management, statin use should be individualized based on the patient’s cardiovascular risk level.

Principles of Dietary Management

Diet is the cornerstone of diabetes management. ADA-recommended dietary principles emphasize: controlling total caloric intake to maintain healthy weight; balanced nutrition including appropriate ratios of carbohydrates, proteins, and fats; choosing low-glycemic-index foods; increasing dietary fiber intake; limiting saturated fats and added sugars.

Regarding carbohydrate intake, the ADA recommends that diabetes patients’ daily carbohydrate intake should be 45%-55% of total calories, with specific amounts adjusted based on the patient’s age, weight, physical activity level, and medication regimen. The main sources of carbohydrates should be whole grains, legumes, vegetables, and fruits, rather than refined grains and sugars.

For protein intake, the ADA recommends daily protein intake should be 15%-20% of total calories. For patients with diabetic kidney disease, protein intake should be appropriately reduced but should not fall below 0.8 grams per kilogram body weight daily. For fat intake, the ADA recommends keeping saturated fat intake below 10% of total calories and increasing monounsaturated and polyunsaturated fatty acid intake.

Exercise Therapy

Exercise is an important component of diabetes management. The ADA recommends adult diabetes patients engage in at least 150 minutes of moderate-intensity aerobic exercise (such as brisk walking, cycling, swimming, etc.) or 75 minutes of vigorous-intensity aerobic exercise per week, combined with strength training 2-3 times per week. Combining aerobic exercise and strength training can better improve blood glucose control and insulin sensitivity.

Blood glucose monitoring should be noted before and after exercise to prevent exercise-induced hypoglycemia. For patients using insulin or insulin secretagogues, medication doses or carbohydrate intake may need adjustment before exercise. Sugar-containing foods should be carried during exercise in case of emergency. For patients with severe cardiovascular disease, retinopathy, neuropathy, or other complications, consulting a doctor before starting an exercise program is recommended.

The effects of exercise are cumulative—even short periods of activity are beneficial. The ADA recommends that sedentary individuals stand and move every 5-10 minutes every 30 minutes. Although this light activity cannot replace a formal exercise program, it can help break the metabolic negative effects of prolonged sitting.

Medication Therapy

For type 2 diabetes patients, if lifestyle intervention cannot achieve blood glucose targets, medication therapy needs to be initiated. Metformin is the first-choice medication for type 2 diabetes—it lowers blood glucose by reducing hepatic glucose production and improving peripheral insulin sensitivity. Metformin has a good safety profile, is affordable, and helps with weight control.

If metformin monotherapy cannot achieve blood glucose targets, the ADA recommends adding a second medication on top of metformin. When choosing a second medication, individualized patient needs should be considered, such as whether the patient has atherosclerotic cardiovascular disease, heart failure, or chronic kidney disease. For these patients, medications with cardiovascular benefits (such as GLP-1 receptor agonists or SGLT2 inhibitors) are priority choices.

Insulin therapy is an important component of diabetes treatment. For type 1 diabetes patients, insulin is an essential therapy. For type 2 diabetes patients, insulin therapy is also needed when other medications cannot control blood glucose. Insulin therapy requires close blood glucose monitoring to prevent hypoglycemia.

Complication Prevention

Chronic complications of diabetes are the main factors affecting patients’ quality of life. Major macrovascular complications include cardiovascular disease (coronary heart disease, myocardial infarction, stroke, etc.) and peripheral vascular disease. Microvascular complications include diabetic retinopathy, diabetic nephropathy, and diabetic neuropathy.

The key to preventing complications is good blood glucose control. Large studies such as UKPDS and DCCT have confirmed that good blood glucose control can significantly reduce the risk of diabetes microvascular complications. For type 2 diabetes patients, comprehensive management of blood pressure, lipids, and smoking cessation is also very important. The ADA recommends that diabetes patients undergo comprehensive eye examination, urine microalbumin detection, and foot examination at least annually.

For patients who have already developed complications, early detection and early treatment can slow disease progression. For example, if detected early, diabetic retinopathy can be treated with laser therapy or anti-VEGF drugs to prevent vision loss. ACEI or ARB medications can slow kidney function deterioration in patients with diabetic nephropathy.

Frequently Asked Questions

Q1: Can diabetes be cured?

Currently, there is no cure for diabetes, but it can be well-controlled through standardized treatment, allowing patients to have a quality of life no different from normal people. For early type 2 diabetes patients, through intensive lifestyle intervention and medication therapy, some patients can achieve diabetes “remission” (meaning no glucose-lowering medications are needed for a period of time, and blood glucose remains normal or near normal).

Q2: Can diabetes patients eat fruit?

Yes. Fruit is an important part of a healthy diet, rich in vitamins, minerals, and dietary fiber. However, it is important to choose fruits with low glycemic indexes, such as apples, pears, oranges, strawberries, etc., and control intake amounts. It is recommended to eat fruit between meals, avoiding consumption immediately after meals to prevent rapid blood glucose elevation.

Q3: Is insulin addictive?

No. Insulin is a hormone essential for the body—the reason diabetes patients use insulin is because the body cannot produce enough insulin or cannot effectively utilize insulin. This is completely different from drug addiction. Many type 2 diabetes patients, after good blood glucose control, can reduce or stop insulin use according to doctor’s recommendations and switch to oral glucose-lowering medications.

This content is for reference only and cannot replace professional medical advice. For health concerns, please consult your doctor.