HbA1c & insulin resistance

HbA1c (glycated haemoglobin) reflects the average blood sugar of the past three months. Fasting insulin and glucose give the HOMA-IR index, which is used in blood sugar diagnostics. Insulin resistance sits at the centre of the metabolic syndrome and is considered together with inflammation values, weight, PCOS and the cardiovascular values. A venous blood draw at the practice is required.

What HbA1c and insulin show

Glucose passes freely into red blood cells and attaches there to haemoglobin without an enzyme, mainly to the end of its beta chain. After an intermediate step, this glycation becomes permanent and lasts as long as the blood cell lives – about three to four months. How much HbA1c forms depends on how high blood sugar was during this time; the last few weeks count the most. Insulin from the beta cells of the pancreas lowers blood sugar: it brings glucose transporters (GLUT4) to the surface of muscle and fat cells, inhibits sugar release from the liver and slows fat breakdown. Fasting insulin and glucose together show how much insulin the body needs for a stable blood sugar.

Low HbA1c or insulin – what does it mean?

A low HbA1c shows a low average blood sugar – or that the red blood cells live for a shorter time and have less time for glycation. This is the case with increased breakdown of red blood cells, after blood loss, after transfusions and in pregnancy; the value is then lower than the blood sugar would suggest. A low fasting insulin with normal blood sugar shows high insulin sensitivity: muscles and liver already respond to little insulin. If, on the other hand, insulin is low while blood sugar is high, the beta cells are releasing too little – for example in type 1 diabetes or in later phases of type 2 diabetes.

High HbA1c or insulin – what happens in the body?

With insulin resistance, muscles, liver and fat tissue respond less strongly to insulin. The beta cells compensate for a long time with more insulin, so that blood sugar initially stays normal but fasting insulin rises. The liver continues to release sugar, fat tissue releases more fatty acids, the liver becomes fatty, triglycerides rise and HDL falls; in the kidneys, high insulin retains sodium, which can raise blood pressure, and in the ovaries it promotes the production of male hormones. When compensation is no longer sufficient, blood sugar and HbA1c rise. Persistently raised blood sugar also glycates proteins in vessel walls, nerves, kidneys and the lens of the eye; this produces end products (AGEs) that alter these tissues over years.

The interpretation is given in your report.