Last reviewed by Faculty of Harvard Medical School on January 16, 2013
By Laura J. Hodgdon, Dietetic Intern
Have you ever skipped a meal and felt shaky, dizzy, confused and, more importantly, hungry? If you have, you are not alone. These are symptoms of hypoglycemia, also called low blood sugar. It is usually a result of skipping meals.
Hypoglycemia is uncommon in adults and children older than 10 years, except as a side effect of diabetes treatment. But it can also result from increased exercise or other physical activity, or drinking alcohol on an empty stomach. Other more rare conditions that may lead to hypoglycemia include insulin-secreting tumors of the pancreas and diseases like cirrhosis and hepatitis.
Normally, the body converts carbohydrates in food into a sugar called glucose. Glucose is the main sugar found in blood and is a source of energy for the body and brain.
Foods that are rich in carbohydrates include, but are not limited to:
Hypoglycemia occurs when blood glucose levels drop below 70 mg/dL.
There are two types of hypoglycemia.
1. Fasting hypoglycemia
When the body goes without food usually for more than six hours levels of sugar in the blood drop. This type of hypoglycemia is often seen in heavy drinkers who do not eat; in people with viral hepatitis, cirrhosis, or liver cancer; and in children with carbohydrate metabolic disorders.
Generally, when blood glucose begins to fall, a hormone called glucagon is secreted from the pancreas. Glucagon's job is to signal the liver to break down glycogen the form glucose takes when it is stored in the body and release glucose into the bloodstream. This keeps your blood sugar level within a normal range until you eat again.
2. Postprandial hypoglycemia
This type of hypoglycemia is often caused by the body releasing too much insulin into the blood after eating a carbohydrate-rich meal or food.
Insulin carries glucose into the cells. When there is excessive insulin, too much glucose can move into the cells. This leaves too little glucose in the blood, so glucose levels drop significantly. People who are very thin, who have lost a lot of weight, and women who have most of their excess weight below their waists may have this type of hypoglycemia. A high-carbohydrate/low-fat diet or drinking too much alcohol, for example, may also cause postprandial hypoglycemia.
Hypoglycemia can cause one or more of the following symptoms:
Hypoglycemia can happen suddenly. It is usually mild and can be treated quickly and easily.
The primary goal is to bring glucose levels up first. This can be done by eating or drinking a small amount (15 grams) of a glucose-rich food such as:
For people with diabetes, a simple way to get blood glucose levels up is to follow the "15-15-15" rule. When blood glucose level is less than 70 mg/dL, eat or drink 15 grams of a glucose-rich food, wait 15 minutes and retest blood sugar, then take another 15 grams of carbohydrates if blood glucose level is still less than 70 mg/dL.
Whether you have diabetes or not, it's also important to include a protein with a carbohydrate/starch. This will slow the release of glucose into the bloodstream, so blood sugar levels stay level.
Here are some ways to do this:
If you have diabetes, it's important to talk to your doctor about your diet, medications and exercise because they can all make your blood sugar rise or fall.
Planning ahead is the key to preventing hypoglycemia. Here are a few simple steps you can take everyday to help manage your blood sugar level.
By Laura J. Hodgdon is a Dietetic Intern at Brigham and Women's Hospital