Reactive hypoglycemia

Symptoms vary according to individuals' hydration level and sensitivity to the rate and/or magnitude of decline of their blood glucose concentration.

A crash is usually felt within four hours of heavy carbohydrate consumption. Along with the symptoms of hypoglycemia, symptoms of reactive hypoglycemia include:[7][8][9]

The majority of these symptoms, often correlated with feelings of hunger, mimic the effect of inadequate sugar intake as the biology of a crash is similar in itself to the body's response to low blood sugar levels following periods of glucose deficiency.[10]

The NIH states: "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.[1]

Several other hormones are responsible for modulating the body's response to insulin, including cortisol, growth hormone and sex hormones. Untreated or under-treated hormonal disorders such as adrenal insufficiency (see also Addison's disease[11]) or growth hormone deficiency[12] can therefore sometimes cause insulin hypersensitivity, and reactive hypoglycemia.

Stomach bypass surgery or hereditary fructose intolerance are believed to be causes, albeit uncommon, of reactive hypoglycemia. Myo-inositol or 1D-chiro-inositol withdrawal can cause temporary reactive hypoglycemia.

There are several kinds of reactive hypoglycemia:[13]

1. Alimentary hypoglycemia (consequence of dumping syndrome; it occurs in about 15% of people who have had stomach surgery)
2. Hormonal hypoglycemia (e.g., hypothyroidism)
3. Helicobacter pylori-induced gastritis (some reports suggest this bacteria may contribute to the occurrence of reactive hypoglycemia)[14]
4. Congenital enzyme deficiencies (hereditary fructose intolerance, galactosemia, and leucine sensitivity of childhood)[15]
5. Late hypoglycemia (occult diabetes; characterized by a delay in early insulin release from pancreatic beta-cells, resulting in initial exaggeration of hyperglycemia during a glucose tolerance test)[16]

"Idiopathic reactive hypoglycemia" is a term no longer used because researchers now know the underlying causes of reactive hypoglycemia and have the tools to perform the diagnosis and the pathophysiological data explaining the mechanisms.[13]

To check if there is real hypoglycemia when symptoms occur, neither an oral glucose tolerance test nor a breakfast test is effective; instead, a hyperglucidic breakfast test or ambulatory glucose testing is the current standard.[13][17]

The body requires a relatively constant input of glucose, a sugar produced upon digestion of carbohydrates, for normal functioning. Glucagon and insulin are among the hormones that ensure a normal range of glucose in the human body.[18] Upon consumption of a meal, blood sugar normally rises, which triggers pancreatic cells to produce insulin. This hormone initiates the absorption of the just-digested blood glucose as glycogen into the liver for metabolism or storage, thereby lowering glucose levels in the blood. In contrast, the hormone glucagon is released by the pancreas as a response to lower than normal blood sugar levels. Glucagon initiates uptake of the stored glycogen in the liver into the bloodstream so as to increase glucose levels in the blood.[19] Sporadic, high-carbohydrate snacks and meals are deemed the specific causes of sugar crashes. The “crash” one feels is due to the rapid increase and subsequent decline of blood sugar in the body system as one begins and ceases consumption of high-sugar foods. More insulin than is actually needed is produced in response to the large, rapid ingestion of sugary foods.

Reactive hypoglycemia can usually be relieved by dietary changes:[20]

• Avoiding or limiting sugar intake, including candy, sweet desserts, fruit juice, and drinks with added sugar.[20][21]
• Eating only small amounts of starchy foods, including potatoes, pasta, breakfast cereals, and rice.[20]
• Eating a variety of foods, including:
  • eggs, nuts, dairy products, tofu, beans, lentils, meat, poultry, fish, or other sources of protein with every meal or snack,[20]
  • whole-grain carbohydrates, such as eating whole wheat bread instead of white bread,[20] and
  • more fruits and vegetables (but not fruit juice), with 5 A Day being a recommended goal for most people.[20]
• Eating more high-fiber foods, such as lentils, beans, pulses (legumes), leafy greens, and most fruits and vegetables.[20]

Other tips to prevent sugar crashes include:

• Exercising regularly, as exercise increases cellular sugar uptake, which decreases excessive insulin release.[22][23]
• Avoiding eating meals or snacks composed entirely of carbohydrates;[20] simultaneously ingest fats and proteins, which have slower rates of absorption;
• Consistently choosing longer lasting, complex carbohydrates to prevent rapid blood-sugar dips in the event that one does consume a disproportionately large amount of carbohydrates with a meal;
• Monitoring any effects medication may have on symptoms.[4]

Low-carbohydrate diet and/or frequent small meals is the first treatment of this condition. The first important point is to add small meals at the middle of the morning and of the afternoon, when glycemia would start to decrease. If adequate composition of the meal is found, the fall in blood glucose is thus prevented. Patients should avoid rapidly absorbed sugars and thus avoid popular soft drinks rich in glucose or sucrose. They should also be cautious with drinks associating sugar and alcohol, mainly in the fasting state.[13]

As it is a short-term ailment, a sugar crash that was not caused by injecting too much insulin does not usually require medical intervention in most people. The most important factors to consider when addressing this issue are the composition and timing of foods.[24]

Acute (short-term) low blood sugar symptoms are best treated by consuming small amounts of sweet foods, so as to regain balance in the body's carbohydrate metabolism. Suggestions include sugary foods that are quickly digested, such as:

• Dried fruit
• Soft drinks
• Juice
• Sugar as sweets, tablets or cubes.[25]

The anti-hypertensive class of medication known as calcium channel blockers could be useful for reactive hypoglycemia as inhibition of the calcium channels on beta islet cells can help prevent an overproduction of insulin after a meal is eaten.[26][27]

Main article: Idiopathic postprandial syndrome

If there is no hypoglycemia at the time of the symptoms, this condition is called idiopathic postprandial syndrome. It might be an "adrenergic postprandial syndrome" — blood glucose levels are normal, but the symptoms are caused through autonomic adrenergic counterregulation.[28] Often, this syndrome is associated with emotional distress and anxious behaviour of the patient.[13] This is often seen in dysautonomic disorders as well. Dietary recommendations for reactive hypoglycemia can help to relieve symptoms of postprandial syndrome.

• Spontaneous hypoglycemia
• Refeeding syndrome

• Açbay O, Celik AF, Kadioğlu P, Göksel S, Gündoğdu S (1999). "Helicobacter pylori-induced gastritis may contribute to occurrence of postprandial symptomatic hypoglycemia". Dig. Dis. Sci. 44 (9): 1837–42. doi:10.1023/A:1018842606388. PMID 10505722. S2CID 22096584.

• Article about hypoglycemia at eMedicine