Definition
The altered tolerance to glucose or IGT (acronym of Impaired Glucose Tolerance ) is a condition in which the glycaemia - two hours after the oral load with 75 grams of glucose - takes values between 140 mg / dl and 200 mg / dl .
Diagnosis
The test used to diagnose impaired glucose tolerance is called OGTT or an oral glucose loading curve: after a fast of at least eight hours, a preliminary glycemic test is performed on a small venous blood sample; at the end of the collection the patient is invited to ingest a liquid meal based on 75 grams of glucose dissolved in 250-300 ml of water.
Blood glucose is then monitored at regular intervals, so as to reconstruct the time course of blood glucose levels. The most indicative data is obtained after 120 minutes from ingestion: if in this instant the glycaemia is between 140 and 200 mg / dl the glucose intolerance test is positive.
In the presence of IGT, fasting glucose levels may be absolutely normal or only slightly increased; in the latter case we speak of impaired fasting glycaemia or IFG associated with IGT.
| Glycemic levels | Normal | Altered blood sugar a fasting (IFG) | Altered tolerance glucose (IGT) | Diabetes mellitus (DM) | ||||
|---|---|---|---|---|---|---|---|---|
| Venous plasma | Fasting | 120 ' | Fasting | 120 ' | Fasting | 120 ' | Fasting | 120 ' |
| (Mg / dl) | <110 | <140 | > 110 * - <126 | <140 | <126 | > 140 <200 | > 126 | > 200 |
| (Mmol / l) | <6.1 | <7.8 | > 6.1 - <7.0 | <7.8 | <7.0 | > 7.8 | > 7.0 | > 11.1 |
1999 WHO Diabetes criteria - Interpretation of Oral Glucose Tolerance Test - OGTT
*> (100 mg / dl according to the ADA - American Diabetes Association)
Health risks
The impaired glucose tolerance is characterized by an objective anomaly of glucose metabolism. Since the glycemic values remain however below the threshold level necessary to formulate the diagnosis of diabetes, this anomaly has overall dimensions contained.
Even if it is "only" a pre-diabetic stage, the feedback from IGT must not be underestimated. In fact, compared to the euglycemic subject, the patient with impaired glucose tolerance is exposed to a greater cardiovascular risk, especially with regard to ischemic heart disease.
The impaired glucose tolerance is typically associated with the metabolic syndrome, characterized by the presence of insulin resistance, compensatory hyperinsulinemia, hypertriglyceridemia, reduced levels of HDL cholesterolemia and arterial hypertension. The common thread, as well as the main causal agent, of these pathologies is overweight, especially when the excess fat is concentrated on a visceral level.
What to do
The main intervention strategy to bring post-prandial glycemic levels back to normal is therefore based on approaching or maintaining a healthy weight. This result is achieved by limiting the intake of calories, carbohydrates, especially the simple ones, and saturated fats, while increasing the consumption of fresh vegetables.
To learn more, read: Example diet for Diabetes Mellitus type 2
Physical activity is also very important; if after a sin of gluttony a quick walk to help the activity of brown adipose tissue can be helpful, walk briskly for thirty minutes a day (or at least do it 4 times a week), and prefer some healthy flight of stairs to the lift, is an extraordinarily effective strategy to prevent diabetes and improve general well-being and lipid profile (cholesterolemia, triglyceridemia, etc.).
To learn more, read: Physical activity and type 2 diabetes
In the presence of an altered glucose tolerance, some supplements, in particular those based on vegetable fibers, can be helpful, whose use must be discussed in advance with your doctor.
To learn more, read: Medicinal Plants and Diabetes
Furthermore, if deemed appropriate, the practitioner can recommend the use of real drugs, able to act on both glycemic levels and excess weight (see acarbose and orlistat).
