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The Type Diabetes 2 Diet Book
By CALVIN EZRIN, ROBERT E. KOWALSKI
The McGraw-Hill Companies, Inc.Copyright © 2011Calvin Ezrin and Robert E. Kowalski
All rights reserved.
THE CRITICAL ROLE OF DIET IN DIABETES
The first recorded diagnosis of diabetes was made by physicians in ancient Egypt. Finding that the urine of patients with the disease tasted sweet, they named the problem mellitus meaning "honey."
Diabetes remains defined as a disease characterized by elevated levels of blood sugar, glucose, caused by a relative deficiency of the hormone insulin. There are two major types of the disease.
The less common, insulin-dependent diabetes mellitus, or Type 1 diabetes, occurs mainly in the young. For that reason it was previously called juvenile diabetes. Accounting for about 10 percent of all cases, Type 1 results from a near total destruction of the beta cells of the pancreas that make insulin. Type 1 is often initiated by a virus attack and a subsequent malfunctioning of the body's own immune system that destroys the cells of the pancreas that produce insulin. Type 1 diabetes patients are rarely overweight at the onset of their illnesses, but they can gain weight easily owing to the insulin treatment required for survival.
The more common, second form of this endocrine disturbance is noninsulin-dependent diabetes mellitus, now termed Type 2 diabetes. It is not associated with insulin deficiency but rather with a substantial resistance to the hormone's blood sugar-lowering effect. Most typically, Type 2 develops in adulthood and was previously known as maturity-onset diabetes. Often Type 2 diabetes patients have normal or even increased levels of insulin in their blood but not in sufficient amounts to keep the blood sugar within normal limits. About 90 percent of these patients are obese in medical terms.
Diet has been linked with diabetes from the beginning, and it remains a critical component of treatment today. In fact, an understanding of how dietary management influences the disease is the first step in controlling it.
INSULIN RESISTANCE AND HYPERINSULINISM
While the overweight condition of diabetes patients is at least partially the result of poor eating habits, the phenomena of insulin resistance and hyperinsulinism promote weight gain and make weight loss particularly difficult. Thus, most efforts at weight control for Type 2 diabetics are frustrating and ultimately end in failure. Only when the factors of insulin resistance and hyperinsulinism are taken into consideration can one expect to succeed.
What causes insulin resistance? In Type 2 diabetes it is a strongly inherited selective defect in blood sugar regulation. This affects muscle predominantly but also involves the liver and fat tissue.
Insulin is necessary to metabolize glucose for the body to use it as fuel in the cells. But in diabetic patients, glucose resists this action of insulin. Viewed another way, the insulin is less capable of metabolizing glucose in the diabetic patient than those without diabetes. In response, the body produces additional insulin in an effort to metabolize the rising levels of sugar in the blood. Ultimately, an excessive level of insulin results, a condition termed hyperinsulinism.
For a time, the additional insulin may be sufficient to maintain relatively normal blood sugar levels. But this is a catch-22 situation. Increased insulin levels favor a gain in fat weight, which, in turn, is another important cause of insulin resistance. Fat tissue produces severe chemicals (adipokines) that inhibit the muscles' ability to utilize glucose as fuel or for storage as glycogen.
There comes a time when sufficient weight is gained so that the combined forms of insulin resistance exceed the ability of the pancreas to respond with adequate insulin secretion. At that point, the person is diagnosed with diabetes. Research indicates that a Type 2 diabetes patient has a subtle defect in the pancreas's ultimate ability to make as much insulin as can a nondiabetic individual, whose pancreas has considerable potential reserve capacity. Often, however, excess insulin also produces diabetics who may then require insulin control, starting with diet and exercise as treatment.
Even in the nondiabetic, insulin is involved with production of the "bad" cholesterol carrier known as low-density lipoproteins, or LDL.
At the same time, insulin lowers levels of the "good" cholesterol carrier, high-density lipoproteins (HDL), and strongly stimulates growth of certain cells that play pivotal roles in arterial disease. Imagine, then, what can happen when excessive amounts of insulin circulate through the blood. All those negative functions are increased tremendously. This connection explains some of the reasons why diabetes patients are at significantly greater risk of heart disease and other cardiovascular complications so common in diabetics.
Interestingly, while we typically think of insulin in positive terms, there is a dark side to this hormone.
The landmark Diabetes Control and Complications Trial showed conclusively that good blood sugar control led to significantly better outcomes. That is, Type 1 patients who had "tight control" over their glucose levels suffered fewer complications involving the eyes, nerves, kidneys, and blood vessels. Since Type 2 diabetics develop similar complications, it was reasonable to conclude that good control of blood sugar would be equally desirable for them as well. In the case of small blood vessel-related complications this is true. But regarding large vessel events such as heart disease, stroke, and gangrene, there is some concern that the extra insulin required for good control may be harmful.
Both high blood sugars and high blood insulin levels are likely contributors to Type 2 diabetes large vessel complications. Ideally, levels of sugar and insulin should be normalized. This, happily enough, can be done by following the weight control program detailed in this book.
Excessive secretion of insulin is invariably higher in obese individuals than their lean counterparts. Both obese and lean individuals will release additional insulin in response to meals. But the more obese the individual, the more elevated the plasma insulin.
Those with the lowest fasting insulin have the greatest blood sugar response to insulin; those with the highest fasting insulin have insulin resistance. Again, the higher the level of obesity, the greater the insulin resistance in women and men of all ages, in a linear fashion. This levels off as one becomes very obese.
Insulin metabolizes sugar, making it available to the body's cells. But it also restricts metabolism of fat, leading to fat storage. Hence the obese have less release of free fatty acids and less breakdown of fats, a process known as lipolysis. However, certain fat cells are resistant to the hormone (lypes) that prevents the release of fatty acids, which leads to triglyceride overproduction, the largest found in Type 2 diabetics.
The link between obesity and high blood pressure has long been noted in medicine. Now we know that this is due to insulin resistance; there is a high prevalence of hypertension in insulin-resistant individuals. Indeed, it is possible to actually measure the influence of weight on blood pressure. For every pound (2.2 kilograms) of weight gained in excess of one's healthy weight, blood pressure goes up 0.2 to 0.3 mm/Hg (millimeters of mercury on the doctor's blood pressure meter).
WEIGHT CONTROL AND DIABETES
Weight control from a low carbohydrate diet and a reasonable program of physical exercise are the two most critical components of effective diabetes management. Since most Type 2 diabetics are overweight, the diet prescribed should be low in calories so that stored fat must be with drawn
Excerpted from The Type Diabetes 2 Diet Book by CALVIN EZRIN. Copyright © 2011 by Calvin Ezrin and Robert E. Kowalski. Excerpted by permission of The McGraw-Hill Companies, Inc..
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