Hypoglycemia frequently `diagnosed' but rarely true


Q. I'm healthy, but often feel shaky and lightheaded after eating sugar. Does this mean I'm hypoglycemic?

A. Most likely, no. True hypoglycemla is an abnormally low blood sugar, below 50. That's very unusual in people without diabetes, says Mayer B. Davidson, M.D., an endocrinologist and professor at the University of California at Los Angeles, though it can also hit those who've had stomach surgery, those with rare tumors, conditions of the pituitary, adrenal, liver or kidneys, and those who drink too much alcohol without eating.

Under normal conditions, carbohydrates in the food you eat are broken down to the simple sugar glucose. Insulin, a hormone, enables glucose to move from the bloodstream into cells, where it's needed for fuel. The brain in particular needs a steady supply. The liver stores any excess for later use, so blood sugar can stay in a normal range at all times. The vast majority of adults are able to maintain blood sugar in a remarkably narrow range (70 to 120), even after eating a lot of sugar, exercising or fasting.

But in rare cases, healthy people may suffer reactive hypoglycemia--a type of hypoglycemia in which the body overreacts to the intake of sugar. This sends blood sugar soaring, which triggers the release of excessive insulin, causing blood sugar to plummet a few hours after eating. Adrenaline then kicks in, stimulating the liver to dump sugar into the blood to "correct" the deficiency and ward off harm to the brain.

Anxiety can also trigger the release of adrenaline, causing the same nervousness, sweating, pounding heart, trembling and faintness as in hypoglycemia. So the two conditions are easily confused, especially if the mere anticipation of symptoms causes anxiety. Many people who experience vague, anxiety-like symptoms believe they have hypoglycemia or are given that diagnosis based on symptoms alone. But only rarely are low blood sugar levels present when these symptoms appear. Another theory suggests some people are simply more sensitive to slight fluctuations in blood sugar than others, even though levels are in the normal range.

If you suffer suspicious symptoms, see your doctor. To diagnose hypoglycemia requires a proper work-up. An oral glucose tolerance test, once commonly used, gives too many false positives, says Davidson. Only when low blood sugar consistently coincides with symptoms and they subside within five to 15 minutes after eating, is hypoglycemia confirmed, he says.

If diagnosed with reactive hypoglycemia, here's what helps:

Eat five or six small meals a day that contain a mix of complex carbohydrates (whole grains, vegetables, legumes), protein and some fat.
Avoid eating sugary foods by themselves. Eat them with other foods to blunt their impact.
Limit caffeine, which can cause mild anxiety-like symptoms.
If symptoms arise, drink juice or eat some fruit or hard candy right away.
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