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Reactive Hypoglycemia

Two types of hypoglycemia can occur in people who do not have diabetes:

• Reactive hypoglycemia, also called postprandial hypoglycemia, occurs within 4 hours after meals.
• Fasting hypoglycemia, also called postabsorptive hypoglycemia, is often related to an underlying disease.

Symptoms of both reactive and fasting hypoglycemia are similar to diabetes-related hypoglycemia. Symptoms may include hunger, sweating, shakiness, dizziness, light-headedness, sleepiness, confusion, difficulty speaking, anxiety, and weakness.

To find the cause of a patient’s hypoglycemia, the doctor will use laboratory tests to measure blood glucose, insulin, and other chemicals that play a part in the body’s use of energy.

Diagnosis
To diagnose reactive hypoglycemia, the doctor may:

• ask about signs and symptoms
• test blood glucose while the patient is having symptoms by taking a blood sample from the arm and sending it to a laboratory for analysis
• check to see whether the symptoms ease after the patient’s blood glucose returns to 70 mg/dL or above after eating or drinking
• A blood glucose level below 70 mg/dL at the time of symptoms and relief after eating will confirm the diagnosis. The oral glucose tolerance test is no longer used to diagnose reactive hypoglycemia because experts now know the test can actually trigger hypoglycemic symptoms.

Causes and Treatment
The causes of most cases of reactive hypoglycemia are still open to debate. Some researchers suggest that certain people may be more sensitive to the body’s normal release of the hormone epinephrine, which causes many of the symptoms of hypoglycemia. Others believe deficiencies in glucagon secretion might lead to reactive hypoglycemia. Low blood sugar levels after eating may also be an early sign of prediabetes (or diabetes) as the body may over-produce insulin in response to hyperglycemia after meals, leading to subsequent hypoglycemia.

A few causes of reactive hypoglycemia are certain, but they are uncommon. Gastric—or stomach—surgery can cause reactive hypoglycemia because of the rapid passage of food into the small intestine. Rare enzyme deficiencies diagnosed early in life, such as hereditary fructose intolerance, also may cause reactive hypoglycemia.

To relieve reactive hypoglycemia, some health professionals recommend:

• eating small meals and snacks about every 3 hours
• being physically active
• eating a variety of foods, including meat, poultry, fish, or nonmeat sources of protein; starchy foods such as whole-grain bread, rice, and potatoes; fruits; vegetables; and dairy products
• eating foods high in fiber
• avoiding or limiting foods high in sugar, especially on an empty stomach

The doctor can refer patients to a registered dietitian for personalized meal planning advice. Although some health professionals recommend a diet high in protein and low in carbohydrates, studies have not proven the effectiveness of this kind of diet to treat reactive hypoglycemia.



Adapted and excerpted from NIDDK and NIH.

Reviewed by Jason C. Baker, M.D. 7/12