by Dr. Joseph Debé
From fatigue to hair loss, from anxiety to obesity, impairments in carbohydrate metabolism can be the underlying cause. One researcher has concluded that 7 out of 10 Americans have some degree of abnormal carbohydrate metabolism. The Carbohydrate Challenge Test is the premier test to uncover this source of poor health, accelerated aging, and premature death.
Although carbohydrate metabolism is a very complex process, two important players are glucose (blood sugar) and the pancreatic hormone, insulin. Blood glucose is the main fuel supply for the brain. If glucose levels fall too low (or too rapidly), the central nervous system (brain) is adversely affected by this interruption in its fuel supply. Symptoms that can result from low blood sugar include: hunger, fatigue, irritability, mood swings, anxiety, nervousness, confusion, headache, heart palpitations, blurred vision, dizziness, trembling, sudden profuse sweating, awakening in the middle of the night, and, in severe cases, loss of consciousness. On the flip side, elevated blood glucose is very destructive to body tissues. This is exemplified by the complications of diabetes mellitus: cardiovascular disease and nerve, eye, and kidney damage.
The body needs blood glucose levels to be maintained within a narrow range. When blood sugar rises, the pancreas secretes insulin, which enables glucose to be transported into the cells. When blood sugar levels fall too low or too quickly, the body produces increased levels of the insulin-opposing hormones, cortisol, glucagon, epinephrine, norepinephrine and growth hormone to restore higher levels.
One of the most common health misconceptions I find with my patients involves the subject of carbohydrate metabolism. When I suggest the patient should have a Carbohydrate Challenge Test, the patient often responds, "I was already checked for diabetes." The belief, with respect to carbohydrate metabolism, is that either you are diabetic or you are normal. Reality is (as with all functions in the body) that there is a continuum, from normal, to overt pathology (diabetes). Most people start off with normal carbohydrate metabolism. Over years, improper diet, lifestyle and stress gradually cause alterations in carbohydrate metabolism. The first change that occurs is what is called reactive hypoglycemia, which is a rapid rise in blood sugar followed by an excessive burst of insulin secretion with resultant "crashing" blood sugar levels. (Eating large amounts of refined carbohydrates like bread, pasta, cookies, cakes, muffins, crackers, bagels, soda, fruit juice, cereals, and French fries is usually the most important factor in causing a rapid rise in blood sugar levels.) The body then responds to the insulin-stimulated blood sugar dive by secreting the insulin-opposing hormones in order to raise blood sugar levels. How do these hormones raise blood sugar? By releasing stored sugar from liver and muscle and by converting body protein (primarily muscle) into sugar. This is obviously an undesirable process to have occurring on a regular basis.
The next step along the path of altered carbohydrate metabolism, after reactive hypoglycemia, is insulin resistance. Insulin resistance is a term that refers to the body's cells (liver, muscle, and fat cells) not responding efficiently to insulin's signals to transport sugar from the blood. The body compensates for this by producing more insulin. Chronically elevated insulin levels will result in cellular insulin resistance. Hyperinsulinemia (high blood levels of insulin) and insulin resistance occur together and perpetuate each other. When the cells of the body are continually exposed to elevated insulin levels, they begin to "tune-out" insulin's message to transport sugar. The pancreas responds, "Hey! You're not listening to me! I'll have to shout!" More insulin is secreted to get the message through. With the aid of additional insulin, the sugar is transported into the cells, and blood sugar levels are kept in the normal range. There are, however, very serious consequences to chronically elevated insulin levels. Insulin has many effects in the body, beyond glucose transport. Insulin influences genetic expression (which genes are turned on, which are turned off). For example, insulin increases the activity of the enzyme that produces cholesterol in the liver. Hyperinsulinemia is the driving force behind most cases of high blood cholesterol. Elevated insulin levels adversely impact widespread bodily functions. Some of the results of hyperinsulinemia are: increased appetite, increased triglyceride (fat) production, body fat storage, fatty infiltration of muscle cells, reduced burning of body fat, stress, anxiety, fatigue, inflammation, fibromyalgia, depression, increased appetite, increased fat around the midsection ("apple-shape" or visceral adiposity), sleep apnea, gout, heart disease, stroke, osteoporosis, Alzheimer's disease, certain cancers, fatty liver, liver fibrosis and cirrhosis, kidney dysfunction, parasympathetic nervous system dysfunction, retinopathy, type 2 diabetes, impaired wound healing, immune suppression, Sarcopenia (age-associated loss of lean healthy body tissue), reproductive disorders, irritability, fluid retention, hypertension, high blood cholesterol, insomnia, skin wrinkles, arthritis, reduced thyroid function, and acceleration of the aging process.
One common effect of hyperinsulinemia is polycystic ovary syndrome. This condition is characterized by cessation of periods or infrequent and scanty blood flow, chronic lack of ovulation, ovaries with multiple cysts, weight gain and increased fat around the midsection, infertility, mood swings, fatigue, increased blood triglycerides and reduced HDL cholesterol, scalp hair loss, male pattern hair growth, and acne. Elevated insulin increases adrenal and ovarian production of androgens ("male" hormones like testosterone) and reduces the liver's production of sex hormone binding globulin. Lower sex hormone binding globulin results in increased levels of free (biologically active) testosterone. An elevated level of androgens is the most common hormonal abnormality in premenopausal women, affecting an estimated 1 out of 10.
The next step in deterioration of carbohydrate metabolism is continuation of hyperinsulinemia combined with rising blood sugar levels. In this stage, there is waning ability of the pancreas to produce enough insulin to overcome cellular resistance and glucose transport diminishes. This condition is called impaired glucose tolerance. In this state, fasting blood glucose levels are between 110 and 125.
When things deteriorate further and blood sugar continues to rise, a new label is used: diabetes. The higher the blood sugar, the more serious are the health effects. However, most people will never become diabetic but will, nevertheless, suffer the ill effects of hyperinsulinemia-insulin resistance.
Measurements of fasting blood sugar levels are only slightly more valuable than screen doors on submarines. Unless the body's metabolism has deteriorated to the point of impaired glucose tolerance or diabetes, the message patients come away with from analysis of fasting blood sugar is "no problem". Additionally, I'm shocked how often doctors minimize the significance of impaired glucose tolerance. "Nothing to worry about", patients are told. Actually, a study has found a significant increased risk of death in people with fasting blood sugars of 100 compared to those with values of 85.
The most sensitive way to evaluate carbohydrate metabolism is with a Carbohydrate Challenge Test. The Carbohydrate Challenge Test is like an endocrine system stress test. It picks up subtle insulin resistance that can be missed with fasting glucose and insulin. The Carbohydrate Challenge Test is performed at a blood drawing facility in the following way: A high carbohydrate meal, such as white bread, a banana, and orange juice, is eaten in the morning, after taking a blood and saliva sample. Over the next three hours, additional blood and saliva samples are taken. Glucose, insulin and cortisol are measured from these samples. Heart rate is also monitored during the test, as an indication of autonomic nervous system function. An abnormality in any of these parameters points to the underlying cause of the dysfunction in carbohydrate metabolism. Because the test uses whole food, it can point to delayed emptying of food from the stomach, impaired carbohydrate digestion, and malabsorption as root causes of abnormal blood sugar levels. Natural treatments are customized, based on the exact nature of the results. The Carbohydrate Challenge Test can pick up problems early - before damage has been done - even before symptoms are present.
Because I have a strong family history of diabetes, I did a Carbohydrate Challenge Test a few years ago. It showed the very beginning stage of impaired carbohydrate metabolism- a mild reactive hypoglycemia. With that information, I am able to make dietary and supplement changes to improve things. This is a proactive approach that applies to all aspects of physiology. One can assess how the body is functioning and then take steps to improve health. This is in contrast to the reactive approach of conventional medicine, which takes no action until something "is broken". The average person's carbohydrate metabolism is not addressed until a diagnosis of diabetes can be made. Decades of declining health usually lapse between the initial stages of impairment of physiology and the development of an end-stage disease, like diabetes.
I feel the Carbohydrate Challenge Test is better than the commonly used glucose tolerance test for several reasons. The Carbohydrate Challenge Test gives us a more complete picture of carbohydrate metabolism because it also measures insulin and cortisol levels and assesses autonomic nervous system function. The Carbohydrate Challenge Test is also superior because it utilizes real food, as opposed to a glucose drink. After all, the use of real food better imitates real life. A good illustration of this involves Robert, a patient who consulted me about symptoms of intermittent debilitating fatigue, blurred vision and headaches. He had a comprehensive medical work-up, including eye and neurological examinations, an MRI of the brain, and an EEG. He had also finally persuaded his doctor to do a glucose tolerance test. All results were normal. His symptoms sure sounded to me like hypoglycemia. We had Robert take a Carbohydrate Challenge Test. He did indeed have hypoglycemia! The reason it was picked up with the Carbohydrate Challenge Test but not with the glucose tolerance test is that Robert's low blood sugar levels were due to maldigestion and malabsorption. Part of Robert's treatment involved improving his digestion and absorption. His symptoms quickly improved.