By Dr Ananya Mandal, MD
Hypoglycemia or low blood sugar is a condition where blood levels of glucose drop below a critical level. Glucose provides energy for various bodily functions and is therefore vital for survival.
Glucose is one of the most important sources of energy derived from the foods that we ingest. One of the main sources of glucose is the carbohydrate food group. Rice, potatoes, bread, milk, cereal, sweets, fruits and vegetables are important sources of glucose and other sugars.
Once ingested, glucose is absorbed from food into the blood which carries it into the cells of the body to provide energy for various cell functions. This uptake of glucose is regulated by a hormone called insulin which is produced in the beta cells of the pancreas in the abdomen. Insulin helps the liver and skeletal tissue take up glucose where it is stored in the form of glycogen. Fat cells also take up the glucose and store it as triglycerides. As blood glucose becomes lower, another hormone called glucagon is released by the pancreas to stop glucose levels becoming too low. Glucagon counteracts the effects of insulin by stimulating the liver to convert stored glycogen into glucose which is then released into the blood.
Glucose in diabetes
In type 1 diabetes, the pancreatic cells that release insulin have been destroyed through autoimmune attack and the body is unable to produce any insulin. Glucose therefore remains in the blood rather than being taken up and utilized by cells. In type 2 diabetes, the blood sugar levels are higher than usual because the amount of insulin produced is too low to enable cells to uptake adequate levels of glucose from the blood. Therefore, type 1 diabetes is caused by a "true" deficiency and type 2 diabetes by a relative deficiency of insulin.
People with diabetes also have an impaired glucagon response to blood sugar levels that have become too low. If diabetics take insulin to lower their blood sugar, this impaired glucagon response may mean blood glucose is not normalized once it has become too low, therefore putting them at risk of hypoglycemia.
Just as hypoglycemia may manifest suddenly, it can also be rapidly corrected by consuming a small amount of glucose-rich food. If left untreated, however, it can lower blood glucose in the brain leading to confusion and unconsciousness, convulsions or even hypoglycemic coma and death. Some of the symptoms include trembling, palpitations, anxiety, sweating, hunger, light headedness, confusion, slurring of speech and fatigue.
Reviewed by Sally Robertson, BSc
Last Updated: Oct 25, 2013