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  • With Mayo Clinic endocrinologist

    Maria Collazo-Clavell, M.D.

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Mayo Clinic Health Manager

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Question

Reactive hypoglycemia: What causes it?

I think I have reactive hypoglycemia. What causes this?

Answer

from Maria Collazo-Clavell, M.D.

Low blood sugar (hypoglycemia) usually occurs while fasting. But reactive hypoglycemia is low blood sugar that occurs after a meal — usually one to three hours after eating. Often, the cause of reactive hypoglycemia isn't clear.

Some researchers suspect that certain people are overly sensitive to the normal release of the hormone epinephrine, which causes many of the symptoms of hypoglycemia. Others believe that a deficiency of glucagon — a hormone that normally offers protection from low blood sugar — may cause reactive hypoglycemia.

In a few cases, reactive hypoglycemia may result from excessive production of insulin by the pancreas (hyperinsulinemia). Reactive hypoglycemia may also occur after stomach surgery or due to certain enzyme deficiencies, which may interfere with the balance between nutrient absorption and insulin secretion.

Signs and symptoms of reactive hypoglycemia may include:

  • Shakiness
  • Clumsiness
  • Dizziness
  • Weakness
  • Sweating
  • Hunger
  • Anxiety
  • Pounding heartbeat
  • Confusion

Reactive hypoglycemia is often difficult to diagnose, since it's possible to have symptoms that are similar to reactive hypoglycemia without actually having the condition. Generally, a medical evaluation is done to determine whether symptoms are caused by low blood sugar — and whether symptoms resolve once blood sugar returns to normal. Further evaluation of reactive hypoglycemia depends on the severity of signs and symptoms.

Reactive hypoglycemia usually doesn't require treatment. If needed, it may help to:

  • Eat several small meals and snacks throughout the day, no more than three hours apart
  • Eat high-fiber foods
  • Avoid or limit sugary foods, especially on an empty stomach
  • Include physical activity in your daily routine
Next question
Hyperinsulinemia: Is it diabetes?
References
  1. Service FJ. Food-stimulated (postprandial) hypoglycemia. http://www.uptodate.com/home/index.html. Accessed Aug. 13, 2008.
  2. Service FJ. Noninsulinoma pancreatogenous hypoglycemia. http://www.uptodate.com/home/index.html. Accessed Aug. 13, 2008.
  3. Hypoglycemia. National Diabetes Information Clearinghouse. http://diabetes.niddk.nih.gov/dm/pubs/hypoglycemia. Accessed Aug. 13, 2008.

AN00934

Oct. 3, 2008

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