• Blood glucose level at or below 40 to 50 mg/dl
• A normal response curve during the first two to three hours of a glucose tolerance test, followed by a decrease of 20 mg or more below the fasting glucose level during the final hours of the test, with symptoms developing during the decrease
Hypoglycemia is low blood sugar (glucose). Normally, the body maintains blood sugar levels within a narrow range through the coordinated effort of several glands. If these control mechanisms are disrupted, hypoglycemia or diabetes (high blood sugar) may result. Americans tend to overstress these control mechanisms because of poor diet and lifestyle habits. As a result, diabetes and hypoglycemia are common diseases.
Hypoglycemia is divided into two main categories: reactive hypoglycemia and fasting hypoglycemia. Reactive hypoglycemia, the more common, is characterized by the development of symptoms of hypoglycemia three to five hours after a meal. Reactive hypoglycemia may also result from drugs used in the treatment of diabetes (see the chapter “Diabetes”).
Some experts have recommended that instead of using the term reactive hypoglycemia, we should call the syndrome increased glycemic volatility or idiopathic postprandial syndrome because absolute glucose levels are not reliable indicators of symptoms. Many times people with glucose levels below 50 mg/dl have no symptoms, while people with symptoms of hypoglycemia can have normal or even elevated glucose levels. Symptoms appear to correlate better with rapid drops in blood glucose than with drops below 50 mg/dl (as discussed below).1–3
Fasting hypoglycemia is rare, as it usually appears only in severe disease states such as pancreatic tumors, extensive liver damage, prolonged starvation, or various cancers, or as a result of excessive insulin dosages in diabetics. Pregnant diabetic women using insulin or oral diabetes medications often experience hypoglycemia but usually do not have symptoms.4
Because glucose is the primary fuel for the brain, low levels affect the brain first. Symptoms of hypoglycemia can range from mild to severe, including headache; depression, anxiety, irritability, and other psychological disturbances; blurred vision; excessive sweating; mental confusion; incoherent speech; bizarre behavior; and convulsions.
Hypoglycemia can promote many detrimental changes in the body, such as increasing the levels of C-reactive protein, a marker for inflammation that is a known risk factor for heart disease.5
Diagnosing Hypoglycemia
The most popular method of diagnosing reactive hypoglycemia is the oral glucose tolerance test. After the patient fasts for at least 12 hours, a baseline blood glucose measurement is made. Then the patient drinks a liquid containing glucose (the amount is based on body weight). Blood sugar levels are measured at 30 minutes, at 1 hour, and then hourly for up to 6 hours. Basically, blood sugar levels greater than 200 mg/dl indicate diabetes. Levels below 50 mg/dl indicate reactive hypoglycemia.
Continuous glucose monitoring is an electronic diagnostic system that requires the insertion of a tiny sensing catheter under the skin of the abdomen. The sensor measures blood sugar and sends this information to a small receiver worn on the patient’s belt for up to one week. A graph showing the average blood sugar reading every five minutes (288 blood sugar readings per day) can then be generated and studied in relationship to food intake, appetite, food cravings, hypoglycemic symptoms, medication, and exercise. This has been shown to be a very useful tool in the diagnosis of, and monitoring of blood sugar control in, diabetes.6
Using continuous glucose monitoring, Michael R. Lyon, M.D., has discovered that most people with weight problems and insulin resistance go through their days with remarkable fluctuations in blood sugar. Dr. Lyon has found that symptoms of hypoglycemia occur when blood sugar drops rapidly, even when blood sugar was above the normal range.
Together with Dr. Lyon, we believe that increased glycemic volatility is at the heart of most weight problems. The data indicate that rapidly fluctuating blood sugar levels are generally related to some degree of insulin resistance and are made worse by excessive consumption of foods with a high glycemic impact.7
THE HYPOGLYCEMIA QUESTIONNAIRE
When all factors are considered (including cost and convenience), the most useful measure of diagnosing hypoglycemia in many cases remains an assessment of symptoms. In general, when symptoms appear three to four hours after eating and disappear after food is again eaten, hypoglycemia should be considered. The questionnaire below is an excellent screening method for hypoglycemia.
Hypoglycemia Questionnaire
|
No |
Mild |
Moderate |
Severe |
Crave sweets |
0 |
1 |
2 |
3 |
Irritable if a meal is missed |
0 |
1 |
2 |
3 |
Feel tired or weak if a meal is missed |
0 |
1 |
2 |
3 |
Dizziness when standing suddenly |
0 |
1 |
2 |
3 |
Frequent headaches |
0 |
1 |
2 |
3 |
Poor memory (forgetfulness) or concentration |
0 |
1 |
2 |
3 |
Feel tired an hour or so after eating |
0 |
1 |
2 |
3 |
Heart palpitations |
0 |
1 |
2 |
3 |
Feel shaky at times |
0 |
1 |
2 |
3 |
Afternoon fatigue |
0 |
1 |
2 |
3 |
Vision blurs on occasion |
0 |
1 |
2 |
3 |
Depression or mood swings |
0 |
1 |
2 |
3 |
Overweight |
0 |
1 |
2 |
3 |
Frequently anxious or nervous |
0 |
1 |
2 |
3 |
Total: ______ |
||||
Scoring: |
||||
5 or less: hypoglycemia is not likely to be a factor |
||||
6 to 15: hypoglycemia is likely to be a factor |
||||
16 or more: hypoglycemia is extremely likely to be a factor |
||||
Although all of the symptoms mentioned in the questionnaire above may be due to hypoglycemia, there are obviously other causes in many cases. However, in the 1970s public interest in hypoglycemia and sugar intake was fueled by a number of books including Sugar Blues by William Duffy, Hope for Hypoglycemia by Broda Barnes, and Sweet and Dangerous by John Yudkin. The popularity of these books and the diagnosis of hypoglycemia were met by much skepticism from the medical community. Editorials in the Journal of the American Medical Association and the New England Journal of Medicine during the 1970s denounced this public interest in hypoglycemia and tried to invalidate the concept of hypoglycemia.8,9
Research in the past 30 years has provided an ever-increasing amount of information concerning the role that refined carbohydrates and faulty blood sugar control play in many disease processes. For example, the term metabolic syndrome is used to describe a set of cardiovascular risk factors including glucose or insulin disturbances, high blood cholesterol and triglyceride levels, elevated blood pressure, and abdominal obesity, all of which are tied to elevated insulin levels and insulin resistance. There is little doubt about what contributes to these problems: the human body was not designed to handle the amount of refined carbohydrates (and salt, saturated fats, and other harmful food compounds) that feature prominently in the diets of many people in the United States and other Western countries.
A substantial amount of information indicates that hypoglycemia (increased glycemic volatility) is caused by an excessive intake of refined carbohydrates, especially added sugar.10,11 Although most medical and health organizations, as well as the U.S. government, have recommended that no more than 10% of a person’s total caloric intake come from added sugars, in fact they account for roughly 30% of the total calories consumed by most Americans.12 The average American consumes more than 100 lb of sucrose and 40 lb of high-fructose corn syrup each year. This sugar addiction plays a major role in the high prevalence of chronic disease in the United States.
Consequences of Hypoglycemia
The brain depends on glucose as an energy source. The association between hypoglycemia and impaired mental function is well known. What is not as well known is the role that hypoglycemia plays in various psychological disorders. For example, despite numerous studies that show a high incidence of abnormal glucose tolerance tests in depressed individuals, rarely is hypoglycemia considered as a cause of depression, and rarely are depressed individuals prescribed dietary therapy.13,14 This is despite the fact that dietary therapy (usually simply eliminating refined carbohydrates from the diet) is occasionally all that is necessary for patients who suffer from depression due to reactive hypoglycemia.
A strong yet controversial link exists between hypoglycemia and aggressive or criminal behavior. Several controlled studies have found that reactive hypoglycemia (as determined by an oral glucose tolerance test) is common among psychiatric patients and habitually violent and impulsive criminals.15,16 Furthermore, abnormal and sometimes emotionally explosive behavior is often observed during the glucose tolerance test itself. In one study, reactive hypoglycemia was shown to induce fire-setting behavior in pyromaniacs.17
Several large studies involving more than 6,000 inmates in 10 penal institutions in three states have now evaluated the effect of dietary intervention on antisocial or aggressive behavior.18,19 In the first study, 174 incarcerated juvenile delinquents were placed on a sugar-restricted diet, while another 102 offenders were placed on a control diet.18 During the two-year study the number of incidents of antisocial behavior was reduced by 45% in the treatment group. The most significant reductions came in assaults (which dropped by 83%), theft (77%), “horseplay” (65%), and refusal to obey an order (55%). Antisocial behavior changed the most in those charged with assault, robbery, rape, aggravated assault, auto theft, vandalism, child molestation, arson, and possession of a deadly weapon.
In the largest study, 3,999 incarcerated juveniles of both sexes were studied over a period of two years.19 This study limited the dietary revisions to replacing sugary soft drinks with fruit juices and replacing high-sugar snacks with unrefined-carbohydrate snacks (e.g., replacing a candy bar with popcorn). When 1,121 young men on the sugar-restricted diet were compared with 884 young men on the control diet, there were significant differences: in the first group: suicide attempts were reduced by 100%, the need for restraints to prevent self-injury was reduced by 75%, disruptive behavior was reduced by 42%, and assaults and fights were reduced by 25%. Interestingly, the dietary changes did not seem to affect the behavior of young women, perhaps suggesting that men react to hypoglycemia differently from women. From an anthropological and evolutionary view, this makes sense. Low blood sugar levels were undoubtedly an internal signal for men to hunt for food.
The link between hypoglycemia and aggressive behavior also extends to men without a history of criminal activity. In one study, a glucose tolerance test was given to a group of men who did not have a history of aggressive behavior or hypoglycemia.16 In these subjects a significant correlation was found between the tendency to become mildly hypoglycemic and scores on questionnaires used to measure aggression. These results indicated that aggressiveness often coincided with hypoglycemia.
Premenstrual syndrome (PMS) is a recurrent condition characterized by troublesome yet often ill-defined symptoms that usually appear 7 to 14 days before menstruation begins. The syndrome is most common in women between 30 and 40 years of age; it affects nearly one out of three women in this age group, and about 10% of those affected may have a significantly debilitating form.
An authority on PMS, Guy Abraham, M.D., attempted to clarify the different forms by subdividing PMS into four distinct subgroups (A, C, D, and H).20 Each subgroup is linked to specific symptoms, hormonal patterns, and metabolic abnormalities (see the chapter “Premenstrual Syndrome” for further information). PMS-C is associated with increased appetite, craving for sweets, headache, fatigue, fainting spells, and heart palpitations. Glucose tolerance tests of PMS-C patients during the 5 to 10 days before their menses typically suggested reactive hypoglycemia (the result of excessive secretion of insulin in response to sugar intake), whereas during other parts of the menstrual cycle the same tests were normal. This excessive insulin secretion appears to be hormonally regulated, but other factors may also be involved.21 Salt enhances the insulin response to sugar, and decreased magnesium levels in the pancreas can result in increased secretion of insulin. Regardless of the cause, women with PMS-C appear to be extremely sensitive to hypoglycemia.
Migraine headaches are probably caused by excessive dilation of a blood vessel in the head (see the chapter “Migraine Headache”). Migraines are a surprisingly common disorder, affecting 15 to 20% of men and 25 to 30% of women at some time in their lives. More than half of patients have a family history of the illness. Hypoglycemia has long been known to be a precipitating factor in migraine headaches.22
Several studies have found that eliminating refined sugar from the diet of migraine sufferers with confirmed hypoglycemia results in significant improvement. In one study of 48 migraine sufferers with reactive hypoglycemia, 27 (56%) showed a greater than 75% improvement in symptoms, 17 (35%) showed a greater than 50% improvement, and 4 (8%) showed a greater than 25% improvement.23
Substantial evidence indicates that reactive hypoglycemia or impaired glucose tolerance is a significant factor in the development of atherosclerosis. Although a high sugar intake leads to rises in triglycerides and cholesterol, the real culprit may be elevations of insulin.24 Abnormal glucose tolerance tests and elevations in insulin secretion are common findings in patients with heart disease.25,26
In addition to playing a role in atherosclerosis, high sugar consumption and reactive hypoglycemia can be a cause of angina and intermittent claudication, a painful cramp that usually occurs in the calf during walking.27,28
Therapeutic Considerations
Dietary carbohydrates play a central role in the cause, prevention, and treatment of hypoglycemia. Simple carbohydrates such as sugars are quickly absorbed by the body; this absorbtion results in a rapid elevation in blood sugar and stimulates a corresponding elevation in serum insulin.
Problems with carbohydrates begin when they are refined, because refining strips them of associated nutrients and increases their rate of absorption. Virtually the entire vitamin and mineral content has been removed from white sugar, white breads, pastries, and many breakfast cereals. When high-sugar foods are eaten alone, blood sugar levels rise quickly, producing a strain on blood sugar control. Some think that the natural simple sugars in fruits and vegetables have an advantage over sucrose and other refined sugars in that they are balanced by a wide range of nutrients that aid in the utilization of the sugars. Of greater importance, though, is the fact that the sugars in whole, unprocessed foods are more slowly absorbed, as they are contained within cells and are associated with fiber and other food elements. Notably, large amounts of fruit juice and even vegetable juice may be a problem for hypoglycemics, as the cell disruption characteristic of juicing increases the rate of the absorption of sugars in the juices.
Currently, more than half of the carbohydrates consumed in the United States are in the form of sugars added to processed foods as sweetening agents. It is important to read food labels carefully for clues to sugar content. Various words are used to describe refined simple carbohydrates, including sucrose, glucose, maltose, lactose, fructose, corn syrup, and white grape juice concentrate.
A Closer Look at Simple Carbohydrates
Glucose is not particularly sweet-tasting compared with fructose and sucrose (which is made of glucose plus fructose). It is found in abundant amounts in fruits, honey, sweet corn, and most root vegetables. Glucose is also the primary sugar unit that makes up most complex carbohydrates.
Fructose or fruit sugar is the primary carbohydrate in many fruits, maple syrup, and honey. Fructose is very sweet, roughly 1.5 times sweeter than sucrose. Although fructose has the same chemical formula as glucose, its structure is quite different. In order to be used by the body, fructose must be converted to glucose within the liver. Pure crystalline fructose and fruit can be consumed in moderation, but high-fructose corn syrup should definitely be avoided. High-fructose corn syrup (HFCS), a distant derivative of corn, was created in the late 1960s and has become a hard-to-avoid staple of the American diet. Many different products use HFCS as an ingredient. It provides the sweetness in everything from soft drinks and fruit beverages to most commercial baked goods, including cookies, crackers, and bread; it’s even found in ketchup. Food companies use so much HFCS because it is very cheap. A single 12-fl-oz can of Coke or Pepsi has as much as 13 tsp of sugar in the form of high-fructose corn syrup. And because the amount of soda we drink has more than doubled since 1970, to about 56 gallons per person a year, so has the amount of high fructose corn syrup we take in. In 2001, we consumed, per person, almost 63 pounds of it, according to the U.S. Department of Agriculture. That translates to an average of 31 tsp a day, and at 16 calories per tsp, that represents a daily intake of 496 calories.
The Glycemic Index
A helpful method of categorizing food on the basis of its ability to alter blood sugar is the glycemic index, developed in 1981 to express the rise of blood glucose after a particular food is eaten.29 The standard value of 100 is based on the rise seen with the ingestion of glucose. The glycemic index ranges from about 20 for fructose and whole barley to about 98 for a baked potato. The insulin response to carbohydrate-containing foods is similar to the rise in blood sugar.
The glycemic index is used as a guideline for dietary recommendations for people with either diabetes or hypoglycemia (see Appendix B). People with blood sugar problems are advised to avoid foods with high values and choose carbohydrate-containing foods that have lower values. However, the glycemic index should not be the only thing guiding your food choices. For example, high-fat foods such as ice cream and sausage may have a low glycemic index, but because a diet high in fat has been shown to impair glucose tolerance, these foods are not good choices for people with hypoglycemia or diabetes.
The Importance of Fiber
Population studies as well as clinical and experimental data show that blood sugar disorders are clearly related to inadequate dietary fiber intake (see the chapter “Diabetes”). Although consumption of refined sugars should be curtailed, the amount of complex carbohydrate sources that are rich in fiber should be increased.
The term dietary fiber refers to the components of the plant cell wall, as well as the indigestible residues from plant foods. Different types of fiber possess different actions. Soluble fiber has the most beneficial effects on blood sugar control. Included in this class are hemicelluloses, mucilages, gums, and pectin. These types of fiber are capable of the following actions:
• Slowing down the digestion and absorption of carbohydrates, thereby preventing rapid rises in blood sugar
• Increasing cell sensitivity to insulin, and thereby preventing the excessive secretion of insulin
• Improving uptake of glucose by the liver and other tissues, and thereby preventing a sustained elevation of blood sugar
The majority of the fiber in most plant cell walls is soluble. Particularly good sources of water-soluble fiber are legumes, oat bran, nuts, seeds, psyllium seed husks, pears, apples, and most vegetables. Everyone’s diet should include large amounts of plant foods to provide adequate amounts of dietary fiber; 50 g of fiber is a healthful goal.
PolyGlycopleX (PGX)
Based upon work with continuous glucose monitoring led by Michael R. Lyon, M.D., many important findings have been uncovered on how to effectively reduce blood sugar volatility. For example, Dr. Lyon confirmed earlier work suggesting that while a low-glycemic-index diet is very important in reducing blood sugar levels, it has little effect on blood sugar volatility.7 He has found that the most effective method of reducing glycemic volatility is a low-glycemic diet with the addition of a novel soluble fiber product called PolyGlycopleX (PGX), which is more viscous and more gel-forming than any other known fiber. This translates to significantly reducing the glycemic impact of any food or meal. Several double-blind studies have shown that PGX reduces after-meal elevations in blood sugar in a dose-dependent manner, independent of the type of food consumed.30–32 Typical dosage of PGX is 1,500 to 5,000 mg before meals.
Chromium
Chromium is vital to proper blood sugar control, as it functions in the body as a key constituent of what is called glucose tolerance factor. Without chromium, insulin’s action is blocked and glucose levels are elevated. Chromium deficiency may be a factor in the tremendous number of Americans who have hypoglycemia or diabetes or who are obese.33 Evidence exists that marginal chromium deficiency is quite common in the United States and may be responsible for many cases of reactive hypoglycemia.
In one double-blind, crossover study of eight female patients, 200 mcg chromium (as chromium chloride) given twice per day for three months alleviated hypoglycemic symptoms and the glucose nadir two to four hours after a glucose load.34 In addition, insulin binding improved and the number of insulin receptors increased.35,36
Alcohol
Alcohol consumption severely stresses blood sugar control and is often a factor contributing to hypoglycemia. Alcohol induces reactive hypoglycemia by interfering with normal glucose utilization, as well as by increasing the secretion of insulin. The resultant drop in blood sugar produces a craving for food, particularly foods that quickly elevate blood sugar, as well as a craving for more alcohol. The increased sugar consumption aggravates the reactive hypoglycemia, particularly in the presence of more alcohol, again owing to alcohol-induced impairment of normal glucose utilization and increased secretion of insulin.
Hypoglycemia is an important complication of acute and chronic alcohol abuse. Hypoglycemia aggravates the mental and emotional problems of the alcoholic. Although acute alcohol ingestion induces hypoglycemia, in the long run it leads to hyperglycemia and diabetes. Eventually the body becomes insensitive to the augmented insulin release caused by the alcohol. In addition, alcohol itself can cause insulin resistance even in healthy individuals.37 There is also evidence from large population studies that alcohol intake is strongly correlated with diabetes.38 The higher the alcohol intake, the more likely it is that an individual will have diabetes.
QUICK REVIEW
• Hypoglycemia is a complex set of symptoms caused by faulty carbohydrate metabolism, almost always induced by a diet too high in refined sugars.
• When all factors are considered (including cost and convenience), assessment of symptoms remains the most useful way to diagnose hypoglycemia in most cases.
• Metabolic syndrome is a term used to describe a cluster of abnormalities that owe their existence largely to a high intake of refined carbohydrates, leading to the development of hypoglycemia, excessive insulin secretion, and glucose intolerance, followed by diminished insulin sensitivity leading to high blood pressure, elevated cholesterol levels, obesity, and ultimately type 2 diabetes.
• When blood sugar levels are low or drop rapidly, the condition can result in dizziness, headache, clouding of vision, blunted mental acuity, emotional instability, confusion, and abnormal behavior.
• Several controlled studies show that hypoglycemia is common in psychiatric patients and habitually violent and impulsive criminals.
• Hypoglycemia has been shown to be a common precipitating factor in migraine headaches.
• Problems with carbohydrates begin when they are refined, because refining strips them of associated nutrients and increases their rate of absorption.
• Chromium is vital to proper blood sugar control, as it functions in the body as a key constituent of glucose tolerance factor.
• Alcohol consumption severely stresses blood sugar control and is often a contributing factor in hypoglycemia.
Exercise
A regular exercise program is an important part of a hypoglycemia prevention and treatment plan. Regular exercise prevents type 2 diabetes and improves many aspects of glucose metabolism, including enhancing insulin sensitivity. Some of the benefits of exercise may stem from the fact that it increases tissue chromium concentrations.39 Another key advantage of exercise is that increasing muscle mass improves glucose stabilization.
TREATMENT SUMMARY
The primary treatment of hypoglycemia is the use of dietary therapy to stabilize blood sugar levels. Reactive hypoglycemia is not a disease; it is simply a complex set of symptoms caused by faulty carbohydrate metabolism induced by an inappropriate diet.
Avoid simple, processed, and concentrated carbohydrates, as well as food choices with a high glycemic load. Eat more foods rich in soluble fiber, such as legumes and low-glycemic vegetables. Frequent, small meals may be more effective in stabilizing blood sugar levels. Avoid alcohol, as it can cause hypoglycemia. See the chapter “Diabetes” for further dietary recommendations.
The recommendations for daily intake of vitamins and minerals given in the chapter “Supplementary Measures” are especially important in hypoglycemia, as many essential nutrients are critical to proper carbohydrate metabolism. In particular, we recommend 200 to 400 mcg chromium per day. Additionally, PGX at a dosage of 1,500 to 5,000 mg should be taken before meals (the higher dosage is recommended for those also wanting to lose weight).
Because the beneficial effects of exercise that improve insulin sensitivity decrease within three days after exercise and are no longer evident after one week of rest, it’s important to exercise regularly.40 Choose an exercise program that is appropriate to your fitness level and that interests you; try to elevate your heart rate to at least 60% of maximum for half an hour three times a week.