Nearly three decades ago scientists observed unexplained increase in fasting blood sugar levels in Type 1 Diabetes patients. Soon enough the same was seen in Type 2 Diabetes as well. This was named the “Dawn phenomenon”. The blood sugar values as well as insulin levels are near normal at night. As the night passes we would expect a decrease in blood sugar levels compared to post dinner readings. But here there is a 15-25mg/dl increase in fasting blood sugar readings.
Obviously this translates as increase in PPBS as well. There can be a rebound increase of about 40mg/dl in the post prandial state irrespective of the treatment.Over a period of time this means the average HbA1c can rise irrespective of our rigorous control.
The test measures blood glucose in a person who has fasted for at least 8 hours and is most reliable when given in the morning. Fasting blood sugar level range (without breakfast) is 70 to 130 mg/dl , It is ideal to have fasting blood suagr levels below 100 mg/dl
Why my fasting blood sugar levels are always high ?
It’s the liver! Liver is responsible for maintaining a constant level of blood sugar levels. Generally when we eat the carbohydrates are used up by our body and the remaining carbs are stored as glycogen in the liver. In order to prevent hypoglycaemia at night in Non-Diabetic people the liver sends out the stored glucose by process called glycogenolysis and gluconeogenesis.
Glycogenolysis means breakdown of glycogen to usable glucose molecules. The main purpose is to maintain a constant supply to various parts of the body in a readily usable form. Our brain especially works only on glucose. It cannot process complex sugars. This processof glycogenolysis happens via two signals. First one in the hormonal levels and second signal is the regulation by our central nervous system.
Dawn phenomenon can result in nearly 15-25mg/dl rise in fasting values, around 40mg/dl increase in post prandial values and HbA1c can rise by 0.38%.
Gluconeogenesis means the liver uses non-carbohydrate substances to generate glucose molecules. Liver uses proteins or lipids for the purpose of Gluconeogenesis. In people with Diabetes the release of glucose by liver just works fine. It is the supporting mechanisms which are haywire. In Diabetes the first and foremost deviation from normal happens when the liver falters to assess the blood glucose concentration. So the glucose released actually raises the blood glucose concentrations beyond the expected level.
Secondly, as the duration of diabetes increases there is progressive decrease of beta cells (insulin producing cells) in pancreas leading to reduced insulin secretion. Finally in Type 2 Diabetes there is decreased sensitivity to insulin.
This means even if near normal insulin levels are maintained in the body the cells are not really interested to take up this insulin. The result is that the liver is releasing glucose in the early morning; Cells are in a resistance phase towards insulin so they do not use this insulin. As time passes the body lags in insulin production to counteract this surge in glucose levels.
Dawn phenomenon can result in nearly 15-25mg/dl rise in fasting values, around 40mg/dl increase in post prandial values and HbA1c can rise by 0.38%. Treatment options may vary. The main goal of treatment is to maintain HbA1c of less than 7. Metformin is known to decrease abnormal glucose output by liver.
The potency of metformin to control this surge of glucose may vary from person to person. The time tested technique to control early morning surge in glucose is to substitute the required amount of insulin itself. This can be done by early addition of basal insulin at night in the treatment regimen.
Such basal insulin acts in two ways. Primarily it counteracts the early morning glucose surge and secondly it prevents the over working of pancreas so that the sub normal beta cells can be preserved for a longer duration. This means the patient can use tablets and insulin in combination for a longer time while achieving the golden number of 7 (HbA1c).
The next question which comes to the mind is why not utilizing other tablets to control this morning surge in blood sugars. The mainstay of treatment of Type 2 Diabetes are
Sulphonylureas can decrease blood sugars but given at night there is always a chance of severe hypoglycaemia and secondly the action of sulphonylureas on control of post prandial sugars is limited.
Alphaglucosidase inhibitors and incretins act mainly on post prandial blood sugars having minimal or no effect on fasting blood sugars.
In order to achieve a good blood sugar control and a good HbA1c it is always ideal to add basal insulin to the treatment regimen once optimal dose of metformin is reached.
This will not only help us keep blood sugars under control but also reduce the chances of diabetes related complications in the long run. The only hindrance to use of insulin is the Poke...!
Fear not, as research is on for development of cost effective and user friendly oral insulin. Let’s all make it our goal to handle blood sugars better and have a sweet life!
Dr.Riyaz Sheriff. Diabetologist by profession. He passed out of medical school in 2005. Diabetes always interested him. With an idea to help people take an informed health decision at times of need he connects via www.riyazsheena.blogspot.in His idea is to spread the message of Diabetes by use of the most powerful tool of recent time – The internet!
Dr. Riyaz Sheriff - Author