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In This Report

•	Highlights
•	Introduction
•	General Dietary Guidelines...
•	Major Food Components
•	Weight Control for Type 2 D...
•	Heart-Healthy Diets
•	Diabetic Exchange Lists
•	Exercise
•	Resources

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•	Diabetes: Type 1
•	Diabetes: Type 2

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Diabetes Diet

Highlights

Diabetes Diet Goals

• Achieve near normal blood glucose levels.
• Protect the heart by controlling lipid and blood pressure levels.
• Maintain reasonable weight.
• Manage or prevent diabetes complications.
• Promote overall health.

Key Dietary Considerations

• Food components include carbohydrates, proteins, and fats.
• Carbohydrates have the greatest impact on blood sugar and should provide 50% to 60% of daily caloric intake. Best carbohydrate food sources are whole grains, nuts, and vegetables.
• Choose monounsaturated fats (like olive oil). Avoid saturated fats and trans fatty acids.
• Limit overall protein consumption. Replace high-fat meats with fish or soy protein.
• Dietary needs vary by individual. Postprandial glucose levels can help determine how various food combinations affect glucose.
• Type 1 diabetics should carefully balance food intake, insulin intake, and energy expenditure. Type 2 diabetics should focus on weight control.

Diet Maintenance Strategies

• Check food labels for calorie, fat, sugar, sodium, and nutrient information.
• Weigh and measure food to ensure an accurate calorie count.
• Regulate timing of meals and do not skip meals.

About Insulin

• Insulin is a hormone produced by the pancreas that helps regulate metabolism.
• Insulin enables glucose to enter muscle, liver, and other cells. Glucose (blood sugar) is produced during the process of food digestion. Glucose is derived from sugar, starches, and other carbohydrates.
• Glucose provides an important energy source for the body.
• Diabetes is caused by insufficient insulin production (type 1 diabetes) or insulin resistance (type 2 diabetes). Insulin irregularities impair metabolism and result in elevated glucose levels.

Glucose Monitoring

• Pre-prandial (before eating) plasma glucose levels between 90-130 mg/dl
• Post-prandial (after eating) glucose levels less than 180 mg/dl.
• Hemoglobin A1C levels less than 7%.
• Blood glucose levels should be checked regularly on a daily basis.

Introduction

The two major forms of diabetes are type 1, previously called insulin-dependent diabetes mellitus (IDDM) or juvenile-onset diabetes, and type 2, previously called non-insulin-dependent diabetes mellitus (NIDDM) or maturity-onset diabetes. [For more details, see Well-Connected Report #9 Diabetes Type 1 and Report #60 Diabetes Type 2.]

Insulin

Both type 1 and type 2 diabetes share one central feature: elevated blood sugar (glucose) levels due to absolute or relative insufficiencies of insulin, a hormone produced by the pancreas. Insulin is a key regulator of the body's metabolism. It normally works in the following way:

• During and immediately after a meal the process of digestion breaks carbohydrates down into sugar molecules (of which glucose is one) and proteins into amino acids.
• Right after the meal, glucose and amino acids are absorbed directly into the bloodstream, and blood glucose levels rise sharply. (Glucose levels after a meal are called postprandial levels.)
• The rise in blood glucose levels signals important cells in the pancreas, called beta cells, to secrete insulin, which pours into the bloodstream. Within ten minutes after a meal insulin rises to its peak level.
• Insulin then enables glucose and amino acids to enter cells in the body, particularly muscle and liver cells. Here, insulin and other hormones direct whether these nutrients will be burned for energy or stored for future use. (It should be noted that the brain and nervous system are not dependent on insulin; they regulate their glucose needs through other mechanisms.)
• When insulin levels are high, the liver stops producing glucose and stores it in other forms until the body needs it again.
• As blood glucose levels reach their peak, the pancreas reduces the production of insulin.
• About two to four hours after a meal both blood glucose and insulin are at low levels, with insulin being slightly higher. The blood glucose levels are then referred to as fasting blood glucose concentrations.

Click the icon to see an image of the liver.

Type 1 Diabetes

In type 1 diabetes, the disease process is more severe than with type 2, and onset is usually in childhood:

• Beta cells in the pancreas that produce insulin are gradually destroyed. Eventually insulin deficiency is absolute.
• Without insulin to move glucose into cells, blood glucose levels become excessively high, a condition known as hyperglycemia.
• Because the body cannot utilize the sugar, it spills over into the urine and is lost.
• Weakness, weight loss, and excessive hunger and thirst are among the consequences of this "starvation in the midst of plenty."

Click the icon to see an image of the pancreas.

Patients become dependent on administered insulin for survival. Dietary control in type 1 diabetes is very important and must focus on balancing food intake with insulin intake and energy expenditure from physical exertion. [See Well-Connected Report #9 Diabetes: Type 1.]

Type 2 Diabetes

Type 2 diabetes is the most common form of diabetes, accounting for 90% of cases. An estimated 16 million Americans have type 2 diabetes, and half are unaware they have it. The disease mechanisms in type 2 diabetes are not wholly known, but some experts suggest that it may involve the following three stages in most patients:

• The first stage in type 2 diabetes is the condition called insulin resistance. Although insulin can attach normally to receptors on liver and muscle cells, certain mechanisms prevent insulin from moving glucose (blood sugar) into these cells where it can be used. Most type 2 diabetics produce variable, even normal or high, amounts of insulin, and in the beginning this amount is usually sufficient to overcome such resistance.
• Over time, the pancreas becomes unable to produce enough insulin to overcome resistance. In type 2 diabetes the initial effect of this stage is usually an abnormal rise in blood sugar right after a meal (called postprandial hyperglycemia). This effect is now believed to be particularly damaging to the body.
• Eventually, the cycle of elevated glucose further impairs and possibly destroys beta cells, thereby stopping insulin production completely and causing full-blown diabetes. This is made evident by fasting hyperglycemia, in which elevated glucose levels are present most of the time.

Obesity is common in type 2 diabetics and this condition appears to be related to insulin resistance. The primary dietary goal for overweight type 2 patients is weight loss and maintenance. Studies indicate that when people with type 2 diabetes can maintain intensive exercise and diet modification programs, many can minimize or even avoid medications. [See Well-Connected Report # 60 Diabetes: Type 2.]

General Dietary Guidelines

The treatment goals for a diabetes diet are the following:

• To achieve near normal blood glucose levels. People with type 1 diabetes and people with type 2 diabetes who are taking insulin or oral medication must coordinate calorie intake with medication or insulin administration, exercise, and other variables to control blood glucose levels. New forms of insulin are now allowing more flexibility in timing meals.
• To protect the heart and aim for healthy lipid (cholesterol and triglyceride) levels and control of blood pressure.
• To achieve reasonable weight. Overweight type 2 diabetics who are not taking medication should aim for a diet that controls both weight and glucose. A reasonable weight is usually defined as what is achievable and sustainable, rather than one that is culturally defined as desirable or ideal. Children, pregnant women, and people recovering from illness should be sure to maintain adequate calories for health.
• To manage or prevent complications of diabetes. People with diabetes, whether type 1 or 2, are at risk for a number of medical complications, including heart and kidney disease. Dietary requirements for diabetes must take these disorders into consideration.
• To promote overall health.

Overall Guidelines. There is no longer a single diabetes diet that will suit everyone. The overall approach is based on the U.S. Dietary Guidelines for healthy eating for all Americans, and includes the following:

• Overall, experts recommend that foods containing carbohydrate from whole grains, nuts, fruits, vegetables, and low- or non-fat milk should be included in any healthy diet.
• Carbohydrates and monounsaturated fat should provide 60 to 70% of calories, but the mix should depend on calorie intake needed for weight loss or maintenance.
• Avoid saturated fats (found in animal products) and trans fatty acids (hard margarines, commercial products, fast foods). In selecting fats or oils, prefer monounsaturated fats (virgin olive oil, canola oil), although also include polyunsaturated oils as well (sunflower, rapeseed). Different studies have reported an association between type 2 diabetes and both saturated fats and trans fatty acids.
• Limit protein. Protein should provide 15% to 20% total calories (less in people with nephropathy). In selecting proteins, eat in moderation and prefer fish or soy protein to poultry or meat. (Avoid, in any case, high-fat meats.)
• When choosing foods with sugar, choose fresh fruits, but do so in moderation.

Some Dietary Approaches for Type 1 or Type 2 Diabetes

Patients should meet with a professional dietitian to plan an individualized diet within the general guidelines that takes into consideration their own health needs. There is no single diet that meets all the needs of everyone with diabetes. For instance, a type 2 diabetic who is overweight and insulin-resistant may need to have a different carbohydrate-protein balance than a thin type 1 diabetic in danger of kidney disease. If one of these approaches works in controlling glucose levels, there is no reason to choose another. Each of them can be effective, but because regulating diabetes is an individual situation, everyone with this condition should get help from a dietary professional in selecting the best method.

Healthy eating habits along with good control of blood glucose are the basic goals in managing this complex disease, and several good dietary methods are available to meet them:

General Dietary Guidelines for Type 2 Diabetes. A simple heart-healthy diet with weight control may be sufficient for people with type 2 diabetes. One study of people with type 2 diabetes compared several diet plans:

• A high-carbohydrate/high-fiber diet.
• A low-fat diet.
• A weight management diet.

After 18 months all groups experienced similar and improved glycolated hemoglobin and cholesterol levels. The researchers concluded that the positive benefits of the diets were derived not from the specific regimens, but because the people in the study were attentive and focused. In other words, any healthy diet works if patients work at it.

On the other hand, the so-called Western diet (higher consumption of red meat, processed meat, French fries, high-fat dairy products, refined grains, and sweets and desserts) poses a high risk for type 2 diabetes. (Of note: in a 2003 study, people with type 2 diabetes who used sucralose (a sugar substitute) and a fat replacer (derived from oats) as part of a low-calorie diet achieved better weight and glucose control than those on a standard diabetic diet.)

General Dietary Guidelines for Type 1 and Insulin-Dependent Type 2 Diabetes. Intricate dietary methods are available for control of blood sugar in type 1 and insulin-dependent type 2 diabetes.

• The most common method for controlling blood sugar is the use of The Diabetic Exchange Lists.
• More sophisticated methods include counting carbohydrate grams and using the so-called glycemic index to determine the impact of carbohydrates on blood sugar.

Monitoring

Tests for Glucose Levels. Both hypoglycemia and hyperglycemia are of concern for patients who are receiving insulin. It is important, therefore, to monitor blood glucose levels carefully. Patients should aim for the following measurements:

• Pre-meal glucose levels of between 90 and 130 mg/dL.
• Bedtime levels of between 110 and 150 mg/dL.

In general, patients who are tightly controlling glucose levels need to take readings four or more times a day. Blood glucose levels are generally more stable in type 2 diabetes than in type 1, so experts usually recommend measuring blood levels only once or twice a day. Different goals may be required for specific individuals, including pregnant women, very old and very young people, and those with accompanying serious medical conditions.

Tests for Glycosylated Hemoglobin. Another test examines blood levels glycosylated hemoglobin, also known as hemoglobin A1c (HbA1c). Measuring glycosylated hemoglobin is not currently used for an initial diagnosis, but it may be useful for determining the severity of diabetes. The test is not affected by food intake so it can be taken at any time. A home test has been developed that might make it easier to measure HbA1c. In general, measurements suggest the following:

• Normal HbA1c levels should be below 7%.
• Levels of 11% to 12% glycolated hemoglobin indicate poor control of carbohydrates. High levels are also markers for kidney trouble.

Other Tests. Other tests are needed periodically to determine potential complications of diabetes, such as high blood pressure, unhealthy cholesterol levels, and kidney problems. Such tests may also indicate whether current diet plans are helping the patient and whether changes should be made. Annual urine tests showing even microscopic traces of a protein known as albumin can also indicate a future risk for serious kidney disease.

Preventing Hypoglycemia (Insulin Shock)

For prevention of long-term complications of diabetes, experts are now recommending that both type 1 and type 2 patients should aim at keeping blood levels as close to normal as possible. Such intensive insulin treatment increases the risk of hypoglycemia, which occurs when blood sugar is extremely low (below 60 mg/dL). The following tips may help avoid hypoglycemia or prepare for attacks.

• Patients are at highest risk for hypoglycemia at night. Bedtime snacks may be helpful.
• Patients who intensively control their blood sugar should monitor blood levels as often as possible, four times or more per day. This is particularly important for patients with hypoglycemia unawareness.
• In adults, it is also particularly critical to monitor blood glucose levels before driving, when hypoglycemia can be very hazardous.
• Diabetic patients on therapies that put them at risk for hypoglycemia should always carry hard candy, juice, sugar packets, or commercially available glucose substitutes designed for diabetic individuals.

Other Factors Influencing Diet Maintenance

Food Labels. Every year thousands of new foods are introduced, many of them advertised as nutritionally beneficial. It is important for everyone, most especially people with diabetes, to be able to differentiate advertised claims from truth. The current food labels show the number of calories from fat, the amount of nutrients that are potentially dangerous (fat, cholesterol, sodium, sugars) as well as useful nutrients (fiber, carbohydrates, protein, vitamins).

Labels also show "daily values," the percentage of a daily diet that each of the important nutrients offers in a single serving. Unfortunately, the daily value is based on 2,000 calories, generally much higher than most diabetics should have, and the serving sizes may not be equivalent to those on the Exchange Lists. Most people will need to recalculate the grams and calories listed on food labels to fit their own serving sizes and calorie needs.

Weighing and Measuring. Weighing and measuring food is extremely important in order to get the correct number of daily calories.

• Along with measuring cups and spoons, choose a food scale that measures grams. (A gram is very small, about 1/28th of an ounce.)
• Food should be weighed and measured after cooking.
• After measuring all foods for a week or so, most people can make fairly accurate estimates by eye or by holding food without having to measure everything every time they eat.

Timing. Meals should not be skipped, particularly for those who are on insulin. Skipping meals can upset the balance between food intake and insulin and also can lead to weight gain if the patient eats extra food too often to offset low blood sugar levels.

The timing of meals is particularly important for people taking insulin:

• Patients should coordinate insulin administration with calorie intake. In general, they should eat three meals each day at regular intervals. Snacks are often required.
• They should try to take an insulin injection 30 minutes before they eat, although this timing could vary, depending on the form. Some experts recommend a fast acting insulin (insulin lispro) at each meal and a longer (basal) insulin at night.

Major Food Components

Carbohydrates

Compared to fats and protein, carbohydrates have the greatest impact on blood sugar. Evidence now suggests that it is the total amount of carbohydrates rather than the specific type that most directly affects blood glucose.

Carbohydrate types are either complex (as in starches) or simple (as in fruits and sugars). One gram of carbohydrates equals four calories. The current general recommendation is that carbohydrates should provide between 50% and 60% of the daily caloric intake.

Complex Carbohydrates. In all cases, complex carbohydrates found in whole grains and vegetables are preferred over those found in starch-heavy foods, such as pastas, white-flour products, and potatoes. Most of these are high in fiber, which is important for health. Whole-grains specifically are extremely important for people with diabetes or at risk for it. [For specific benefits, see Box Whole Grains, Nuts, and Fiber-Rich Foods and see Table Some Examples of Healthy Foods.]

Simple Carbohydrates (Sugar). Sugars are generally one of two types:

• Sucrose (table sugar). Sucrose has also been associated with higher triglycerides and harmful cholesterol levels. And a 2002 study suggested that a high level of sugar consumption may reduce levels of HDL cholesterol, the so-called good cholesterol.

• Fructose (sugar molecule found in fruits). Fructose may produce a slower increase in blood sugar than sucrose, which may have some advantages for people with diabetes. Dark-colored fruits are rich in important vitamins and other nutrients, and studies continue to report their benefits for the heart and health in general. Other fruits, such as apples and grapes also have important food chemicals. (As with any sugar, however, excess use of fructose is associated with triglycerides and harmful cholesterol levels.)

Sugar itself, either as sucrose or fructose, adds calories, increases blood glucose levels quickly, and provides no other nutrients. High level of sugar consumption--whether fructose or sucrose--has been associated with higher triglycerides and lower levels of HDL cholesterol, the so-called good cholesterol. And the high consumption of sugar is most likely one of the factor in the current obesity epidemic. Soda, other sweetened beverages, and fruit juice in fact may be singled out as major contributors to childhood obesity.

People with diabetes should continue to avoid products listing more than 5 grams of sugar per serving, and even fruit intake should be moderate. If specific amounts are not listed, patients should avoid products with either sucrose or fructose listed as one of the first four ingredients on the label. [See Box Fat Substitutes and Artificial Sweeteners.]

Of increasing interest to researchers in the study of possible harm from sugar are advanced glycation end-products (called AGEs), which are end-products of the chemical reaction between sugar and protein. This reaction occurs most intensively when cooking at high temperatures--particularly animal fats. (Steaming or cooking food in water does not produce these chemicals. Low, slow cooking also produces fewer AGEs.) AGEs can also be formed by chemical reactions in the body itself. They are now believed to promote factors in the inflammatory response that cause a number of diseases or their complications, including diabetes and other serious conditions (e.g., Alzheimer's, atherosclerosis, cataracts, and osteoporosis).

The Carbohydrate Counting System. Some people plan their carbohydrate intake using a system called carbohydrate counting. It is based on two premises:

• All carbohydrates (either from sugar or starch) will raise blood sugar to a similar degree. In general, one gram of carbohydrates raises blood sugar by 3 points in people who weigh 200 pounds, 4 points for weights of 150 pounds, and 5 points for 100 pounds.

• Carbohydrates have the greatest impact on blood sugar; fats and protein play only minor roles.

In other words, the amount of carbohydrates eaten (rather than fats or proteins) will determine how high blood sugar levels will rise. There are two options for counting carbohydrates: advanced and simple. Both rely on the collaboration with a physician, dietitian, or both. Once the patient learns how to count carbohydrates and adjust insulin doses to their meals, many find it more flexible, more accurate in predicting blood sugar increases, and easier to plan meals than other systems.

The basic goal is to balance insulin with the amount of carbohydrates eaten in order to control blood glucose levels after a meal. The steps to the plan are as follows:

The patient must first carefully record a number of factors that are used to determine the specific requirements for a meal plan based on carbohydrate grams:

• Multiple blood glucose readings (taken several times a day).

• The time of meals.

• Amount in grams of all the carbohydrates eaten.

• Time, type, and duration of exercise.

• The time, type, and dose of insulin or oral medications.

• Other relevant factors, such as menstruation, illness, and stress.

The patient works with the dietitian for two or three 45 to 90 minute sessions to plan how many grams of carbohydrates are needed. There are three carbohydrate groups:

• Bread/starch.

• Fruit.

• Milk.

One serving from each group should contain between 12 and 15 carbohydrate grams. (Patients can find the amount of carbohydrates in foods from labels on commercial foods and from a number of books and web sites.)

The dietitian creates a meal plan that accommodates the patient's weight and needs, as determined by the patient's record, and makes a special calculation called the carbohydrate to insulin ratio. This ratio determines the number of carbohydrate grams that a patient needs to cover the daily pre-meal insulin needs.

Eventually, patients can learn to precisely adjust their insulin doses to their meals.

It should be noted that patients who choose this approach must still be aware of protein and fat content in foods. They may add excessive calories and saturated fats. Patients must still follow basic healthy dietary principles.

The Glycemic Index. The glycemic index has been developed to determine which carbohydrate-containing food raise blood glucose levels more or less quickly after a meal. The index uses a scale of numbers for specific foods that reflect greatest to least delay in producing an increase in blood sugar after a meal. The lower the index number, the better the impact on glucose levels. Some evidence suggests that the benefit of foods with a low glycemic index is due to their ability to increase insulin levels quickly and so remove blood sugar rather than their ability to slow the release of blood sugar itself.

There are currently two indexes in use. One uses a scale of 1 to 100 with 100 representing a glucose tablet, which has the most rapid effect on blood sugar [See Table The Glycemic Index of Some Foods.] The other common index uses a scale with 100 representing white bread (so some foods will be above 100).

A major 2003 analysis suggested that choosing foods with a low glycemic index scores may have a small but significant effect on controlling the surge in blood sugar after meals. Many of these food are also high in fiber and so have heart benefits as well. Substituting low- for high-glycemic index foods may even help prevent weight gain.

One easy way to improve ones glycemic index is simply to replace starches and sugars with whole grains and legumes (e.g., dried peas, beans, and lentils). However, there are many factors that affect the glycemic index of foods, and maintaining a diet with low glycemic load is not straightforward. The following are some considerations:

• The numbers attributed to each carbohydrate-rich food are not additive. In other words, adding All Bran cereal (index of 49) to a banana (index of 61) does not equal 110.

• Adding certain fats to a food, for example butter to potato, can slow down the potato's impact on blood sugar. One study reported that when patients ate fatty foods first, their blood glucose levels were significantly lower an hour after the meal than when carbohydrates were eaten first.

• Adding foods with organic acids (e.g., pickles, yogurt) to meals may reduce the impact of foods with high glycemic scores on blood sugar. (It should be noted that yogurt alone, however, has the same high glycemic index as regular milk.)

No one should use the glycemic index as a complete dietary guide, since it does not provide nutritional guidelines for all foods. It is simply an indication of how the metabolism will respond to certain carbohydrates. Some experts believe it is too complicated to be practical and that simply tracking carbohydrates, eating healthily, and maintaining a healthy weight is sufficient. Nevertheless, a study on children with type 1 diabetes suggested that it offered as many choices as the exchange diet and they did not report feeling any greater limitations.

Protein

In general, experts recommend that proteins should provide 12% to 20% of calories. This daily amount of poses no risk to the kidney in people without signs of nephropathy. Protein is important for strong muscles and bones. Protein intake in diabetes is complicated, however:

• Some evidence also suggests that a high-protein diet lowers post-meal blood sugar more effectively than standard diets. This might be specifically help for patients with type 2 diabetes.

• On the other hand, protein restriction may be important for insulin-dependent diabetic patients with kidney disease. Evidence now strongly indicates that even moderate restriction of proteins may help slow the progression of nephropathy. A 1999 study indicated that a strict-low protein diet may even delay the need for dialysis in patients with kidney failure. All major studies on restricting protein have used insulin-dependent patients as subjects. It is not yet known if lowering protein would have the same benefits for diabetics with nephropathy who are not insulin-dependent. (Note: Diets that are severely low in both protein and salt and coupled with high fluid intake increases the risk for hyponatremia, a rare condition that can cause fatigue, confusion, and, in extreme cases, can be life-threatening.)

One gram of protein contains four calories. Protein is commonly recommended as part of a bedtime snack to maintain normal blood sugar levels during the night, although studies are mixed over whether it adds any protective benefits against nighttime hypoglycemia. If it does, only small amounts (14 grams) may be needed to stabilize blood glucose levels.

Fish. Fish is probably the best source of protein. Evidence suggests that eating moderate amounts of fish (twice a week) may improve triglyceride and help lower the risks for death from heart disease, dangerous heart rhythms, blood pressure, a tendency for blood clots, and the risk for stroke.

It should be noted that a French study reported a higher incidence of heart attack in men who ate fish daily. Such findings may be due to mercury toxicity, which has harmful effects on the heart. High mercury content has been observed in swordfish and shark and, to a medium extent, in tuna, trout, pike, tilapia (tile fish) and bass.More research is needed to further define the risks and benefits of fish, but at this time most evidence for eating fish two or three times a week is highly positive for most people. [See Beneficial Fats and Oils under Fats and Oils, below.]

Soy. Soy is an excellent food. It is rich in both soluble and insoluble fiber, omega-3 fatty acids, and provides all essential proteins. Not all studies are consistent, but the majority has shown an improvement in at least one of the cholesterol components in people who consumed at least 25 grams of soy protein. Soy may also reduce other heart risk factors, including blood pressure, at least in certain populations.In one 2002 study, soy was associated with better control of blood sugar and lower LDL levels in postmenopausal women with type 2 diabetes. The best sources are soy products (tofu, soy milk) or whole soy protein. Adding soy to lean ground beef may still provide heart benefits and be more acceptable for people who object to soy's taste or its "veggie" image. (Note: Tablets of individual isoflavones--chemicals, such as genistein or daidzein, found in soy--do not appear to offer any advantages. Soy sauce is also not a good source. It contains only a trace amount of soy and is very high in sodium.)

More research is important to determine if soy has long-term complications. Of possible concern, a high intake of soy during pregnancy may have some adverse effect on the fetus, although only animal studies have suggested this.

Meat and Poultry. For heart protection, one 1999 study suggested that it didn't matter if you chose fish, poultry, beef, or pork as long as the meat was lean. (Saturated fat in meat is the primary danger to the heart.) The fat content of meat varies depending on the type and cut. It is best to eat skinless chicken or turkey. However, the leanest cuts of pork (loin and tenderloin), veal, and beef are nearly comparable to chicken in calories and fat and their effect on LDL and HDL levels. It should be noted, however, that even chicken and lean meat do not improve cholesterol levels, and, in terms of cardiac health, fish is a more desirable choice.

Dairy Products. A 2002 study reported a lower incidence of factors related to type 2 diabetes and heart disease (insulin resistance, high blood pressure, obesity, and unhealthy cholesterol) with a high intake of dairy products, including those with a high-fat content. Some researchers suggest the calcium in dairy products may be partially responsible for these benefits. The effects of extra calcium on blood pressure, however, are mixed with some even showing higher pressure. Because many dairy products are high in saturated fats, which are related to heart disease, this study requires confirmatory evidence.

Fats and Oils

Some fat is critical in everyone's diet, but certain fats have good or harmful effects on health, depending on their chemistry. All fats, good or bad, are high in calories compared to proteins and carbohydrates. In order to calculate daily fat intake, multiply the number of fat grams eaten by nine (one fat gram is equal to 9 calories, whether it's oil or fat) and divide by the number of total daily calories desired. One teaspoon of oil, butter, or other fats equals about five grams of fat. All fats, no matter what the source, add the same calories.

People should strive to replace saturated (animal fats) and transfatty acids (commercial fats) with unsaturated fats from plant and fish oils. The American Heart Association and other experts now recommend that the source of most of these unsaturated fats should come from omega-3 fatty acids, which are found in fish and plant sources.

The Chemistry of Fats and Cholesterol. Most of the cholesterol in the body does not come from food but is produced by the liver--stimulated by saturated fats. The dietary key to managing cholesterol, then, lies in understanding some of the major compounds in fats and oils that are becoming important in health:

• Fatty Acids. All fats and oils found in foods are made up of chains of molecules called fatty acids. There are three major chains: saturated fatty acid (found mostly in animal products) and two unsaturated fatty acids--monounsaturated and polyunsaturated fatty acids (found in plant products). The oils and fats that people and animals eat are nearly always mixtures of these three chains, but one type of fatty acid usually predominates in specific oils or fats.

• Essential Fatty Acids. In addition, there are three chemical subgroups of polyunsaturated fatty acids called essential fatty acids: omega-3 and omega-6 polyunsaturated fatty acids, and omega-9 monounsaturated fatty acids.

• Transfatty Acids. To complicate matters, there are also trans-fatty acids, which are not natural but are manufactured by adding hydrogen atoms to polyunsaturated fatty acids (called hydrogenation).

Harmful Fats. Reducing consumption of saturated fats and trans-fatty acids is the first essential step in managing cholesterol levels through diet.

• Saturated Fats. Saturated fats are found predominantly in animal products, including meat and dairy products. They are strongly associated with higher cholesterol level and have been associated with a higher risk for type 2 diabetes. They may be even more dangerous in women than in men. Avoiding fats during the evening meal may be especially helpful. High-fat meals are associated with sudden surges in triglyceride levels and other lipids along with impaired blood flow in the arteries to the heart. (The so-called tropical oils, palm, coconut, and cocoa butter, are also high in saturated fats. Evidence is lacking, however, about their effects on the heart. The countries with the highest palm-oil intake, Costa Rica and Malaysia, also have much lower heart disease rates and cholesterol levels than Western nations.)

• Trans-fatty Acids. Trans-fatty acids are manufactured fats created during a process called hydrogenation, which is aimed at stabilizing polyunsaturated oils to prevent them from becoming rancid and to keep them solid at room temperature. Studies report that high consumption of these fats reduces HDL cholesterol levels, has harmful effects on the linings of the arteries, and may increase the risk for diabetes type 2. In one study, women whose diets were high in trans-fatty acids had a 53% increased risk for heart attack compared to those who consumed the least of those fats. Some experts believe that these partially hydrogenated fats are even worse for the heart than saturated fats. They may also pose a risk for certain cancers. Hydrogenated fats are used in stick margarine and in many fast foods and baked goods, including most commercially produced white breads. (Liquid margarine is not hydrogenated and is recommended.) The FDA has now required that food labels include information on trans-fatty acids.

Beneficial Fats and Oils. It should be noted that some fat is essential for health, and fat is essential for healthy development in children. Public attention has mainly focused on the possible benefits or hazards of monounsaturated (MUFA) and polyunsaturated (PUFA) fats.

• Polyunsaturated fats are found in safflower, sunflower, corn, and cottonseed oils and fish.

• Monounsaturated fats are mostly present in olive, canola, and peanut oils and in most nuts. (Canola is the most unsaturated of all the fats.) Some studies have reported that replacing carbohydrates with monounsaturated fats improves glucose control after meals and reduces triglycerides in people with type 2 diabetes.A study on type 1 patients also reported improved cholesterol levels. Diabetic patients who are overweight, however, should be conscious of the calories in any oils.

Researchers are most interested in the smaller fatty-acid building blocks contained in both oils, which may have more specific effects on lipids. Three important fatty acids are the essential fatty acids omega-3, omega-6, and omega-9.

Omega-3 fatty acids are found in fish oil (docosahexaenoic and eicosapentaneoic acids) and plants (alpha-linolenic acid).

• Docosahexaenoic (DHA) and Eicosapentaneoic (EPA) Acids. DHA and EPA are found in fish oils, and evidence suggests that they have significant benefits for the heart, including reducing sudden death from heart disease, dangerous heart rhythms, inflammation, blood clotting factors, blood pressure, and improving triglyceride levels. Fish oil has little effect on LDL or HDL levels. Its effects on blood glucose levels in people with type 2 diabetes are unclear. These fatty acids may also reduce risks for other disorders, including stroke, rheumatoid arthritis, asthma, ulcerative colitis, some cancers, and mental decline. Three capsules of DHA-EPA supplements are about equivalent to eating one serving of fish.The richest sources of omega-3 fatty acids are oily fish, such as salmon, mackerel, or sardines. [For more information, see Fish under Protein.]

• Alpha-linolenic Acid. Alpha-linolenic acid is a plant precursor of DHA, which means the body can convert it to DHA. Sources include canola oil, soybeans, flaxseed, and certain nuts and seeds (walnut, flax, chia and sometimes pumpkin seed). Some, but not all, studies suggest that oils or foods containing these oils may also be heart-protective. Supplements or foods containing these oils may also protect the heart. For example studies have reported heart protection from flaxseed supplements and also from nuts, such as almonds, macadamia, and walnuts. Nuts are high in calories, although studies in 2002 reported that replacing usual snacks with almonds did not affect the daily diet and significantly reduced cholesterol and other heart disease risk factors. Still, people must be aware of that nuts are not low-calorie snacks.

Omega-6 polyunsaturated fatty acids are found in corn, safflower, soybean, and sunflower oil. PUFA oils containing omega-6 fatty acids constitute most of the oils consumed in the US. Some omega-6 fatty acids are important for health. However, high intake of these fats was associated in one study with weight gain in the abdomen (the so-called apple shape), a risk factor for heart disease.High consumption is also associated with a higher risk for certain cancer and some chronic diseases.

Omega-9 monounsaturated fatty acids are contained in canola and olive oil. Both oils have been associated with health protection.

Research suggests that a healthy balance of all these fats may be important and that our current Western diet contains an unhealthy ratio of omega-6 to omega-3 fatty acids (10 to 1). Omega-9 fatty acids may also contain chemicals that block harmful factors found in omega-6 fatty acids. Researchers are finding then that the most benefits may be found in mixture of all three fatty acids found in both poly- and monounsaturated oils, but in modest amounts that do not add too many calories.

Fat Substitutes. Fat substitutes added to commercial foods or used in baking, deliver some of the desirable qualities of fat, but do not add as many calories. [See Box Fat Substitutes and Artificial Sweeteners.]

Dietary Cholesterol

The story on cholesterol found in the diet is not entirely straightforward. Cholesterol is found only in animal tissues, with high amounts occurring in meat, dairy products, egg yolks, and shellfish. The American Heart Association recommends no more than 300 mg of cholesterol per day. One study estimated, however, that reducing dietary cholesterol intake by 100 mg/day would only produce a 1% decrease in cholesterol levels. Of note, however, are studies indicating that although dietary cholesterol itself does not appear to increase the risk for heart disease in most individuals, people with diabetes, especially type 2, may be an exception. Until more research is done, they should consider avoiding eating eggs or other high-cholesterol foods (such as shrimp) more often than once a week.

Vitamins and Supplements

The value of specific vitamins on health in general and for individual diseases is unclear. Nevertheless, of interest was a 2003 study reporting a significantly lower rate of infections (17%) in people with type 2 diabetes who took a multivitamin and mineral supplement compared to those who took a placebo (93%).

Antioxidant Vitamins E, C, and A. Deficiencies in Vitamins E and beta carotene have been linked to heart disease and also to higher blood glucose levels. These nutrients as well as vitamins C and A have antioxidant effects and other properties that should benefit the heart. However, a number of studies have found no reductions in heart disease in people who have taken antioxidant vitamins. In 2003, the US Preventive Service Task Force concluded that, to date, evidence is insufficient to confirm or refute the benefits of supplements of any of these vitamins in protecting against heart disease. It is important to note, in addition, that each of these supplements may even be harmful to the heart in high doses. [See Box Antioxidants: Pros and Cons.]

Folate and B12 Vitamins. Deficiencies in the B vitamins folate (known also as folic acid) and B12 have been associated with a higher risk for heart disease in some (but not all) studies. Such deficiencies produce elevated blood levels of homocysteine, an amino acid that has been associated with a higher risk for heart disease, stroke, and heart failure. Some studies in 2002, suggest that any risk posed by homocysteine or benefits from folic acid for heart disease are at most modest. One study, however, reported lower failure rates after angioplasty in patients who took folic acid and vitamins B12 and B6. And a major 2002 suggested that lowering homocysteine levels with folic acid would reduce the risk for heart disease by 16% and stroke by 24%. More evidence is needed to determine whether homocysteine plays a causal role in cardiovascular disease and whether the B vitamins are protective. Folate improves blood flow through the arteries, which may be important for the heart, regardless of its effect on homocysteine.

Niacin. Niacin (vitamin B3) is used for lowering unhealthy cholesterol levels. Although vitamin B3 is available over the counter, it can have significant side effects. A physician should prescribe niacin in order to ensure its safety and effectiveness.

[For more information, see Well-Connected Report #39 Vitamins, Carotenoids, and Phytochemicals.]

Salt and Sodium

Most experts recommend salt restriction in people who are hypertensive. Some people, however, are much more sensitive to harmful effects from salt than others:

• People at Risk for Salt-Sensitivity (African Americans, Diabetics, the Elderly). About half of people with hypertension have blood pressure that reacts significantly to salt. Such people are known to be salt-sensitive. High-salt diets in anyone who is salt-sensitive may harm the heart, kidney, and brain and increase the risk for death, regardless of their blood pressure. (Even people with normal blood pressure can be salt-sensitive.) Among those at highest risk for salt sensitivity are African Americans, people with diabetes, and elderly people. A 2001 study, for example, reported that reducing sodium intake in older people, including African Americans, was very effective in controlling their hypertension. Still because testing for salt-sensitivity is not easy, experts recommend that everyone proactively restrict their daily salt-intake.

• Overweight People. Overweight individuals may absorb and retain sodium differently from people with normal weights. In fact, one 1999 study reported that high sodium intake was associated with an increased risk of heart disease and all cause mortality in overweight, but not in normal weight, people. Unfortunately, because overweight people generally consume more calories, they are also likely take in more sodium.

Simply eliminating table and cooking salt can be beneficial. It should be noted, however, that about 75% of the salt in the typical American diet comes from processed or commercial foods, not from food cooked at home, so the benefits of table-salt substitutes are likely to be very modest. Some sodium is essential to protect the heart, but most experts agree that the amount is significantly less than that found in the average American diet. If people cannot significantly reduce the amount of salt in their diets, adding potassium-rich foods might help to restore a healthy balance.

Other Minerals

Calcium. Calcium supplements may be important in older patients with diabetes to help reduce the risk for osteoporosis, particularly if their diets are low in dairy products.

Potassium. Evidence now strongly indicates that a potassium-rich diet can help achieve healthy blood pressure levels, and that potassium supplements can lower systolic blood pressure by 1.8 m Hg and diastolic blood pressure by 1 mm Hg. In fact, there is some evidence that a potassium-rich diet can reduce the risk of stroke by 22% to 40%. Current expert guidelines now support the use of potassium supplements or enough dietary potassium to achieve 3,500 mg per day for people with normal or high blood pressure (who have no risk factors for excess potassium levels). This goal is particularly important in people who have high sodium intake. The best source of potassium is from the fruits and vegetables that contain them. Some potassium-rich foods include bananas, oranges, pears, prunes, cantaloupes, tomatoes, dried peas and beans, nuts, potatoes, and avocados.

Of note, in this regard, certain kidney problems can cause potassium overload. Medications commonly used in diabetes, such as ACE inhibitors or potassium-sparing diuretics, also limit the kidney's ability to excrete potassium. No one should take potassium supplements without consulting a physician. The best source of potassium is from the fruits and vegetables that contain them.

Magnesium. Magnesium deficiency may have some role in insulin resistance and high blood pressure. One study reported that low magnesium levels as measured in blood tests were associated with a higher risk for type 2 diabetes in whites but not in African Americans. Dietary intake of magnesium, however, did not appear to play any role in increasing or reducing risk for either population group. It is more likely that diabetes may cause magnesium loss. A major 2001 study on diet found no effect on blood pressure from magnesium intake from foods. No supplements are recommended at this time for patients with adequate levels of magnesium. The recommended daily allowance is 320 mg. Persons who live in soft water areas, who use diuretics, or who have other risk factors for magnesium loss or ectopic beats may require more dietary magnesium than would others.

Chromium. Some studies have reported an association between deficiencies in the mineral chromium and a higher risk for type 2 diabetes. Studies on fat rats that were given chromium reported improvement in insulin sensitivity and glucose metabolism. Most studies on type 2 patients, however, reported little or no effect on glucose metabolism and some even reported adverse side effects.

Zinc. Many type 2 diabetics are also deficient in zinc; more studies are needed to establish the benefits or risks of taking supplements. Zinc has some toxic side effects, and some studies have associated high zinc intake with prostate cancer.

Fluids: Water, Caffeine, and Alcohol

Water. Many heart risk factors, especially those associated with blood clotting, are elevated with dehydration. In an interesting 2002 study, drinking five or more glasses of water a day was significantly associated with a lower risk for fatal heart events than drinking two or fewer glasses a day. More research is warranted on this simple way of protecting health. (Other fluids, including caffeinated and sugared drinks, were not protective.)

Alcohol. A number of studies have found protection from heart disease and type 2 diabetes with light to moderate intake of any type of alcohol. Some research suggests that alcohol has anti-inflammatory properties that protect arteries from injury. Red wine in particular may have specific benefits for people with type 2 diabetes. It has strong anti-oxidant effects that benefit the heart. Some evidence also suggests that red wine may improve insulin sensitivity and reduce blood glucose levels and may even protect against type 2 diabetes. Note: In those taking insulin or sulfonylureas, however, alcohol may cause a hypoglycemic reaction, of which the drinker may not be aware. Women who are pregnant or at risk for breast cancer and anyone at risk for alcohol abuse should not drink alcohol.

Tea. Although it contains caffeine, tea, both black and green, is often cited for its health benefits. Green tea is especially is rich in chemicals that offer protection against damaging forms of LDL. In one study, for example, higher intake, particularly by women, was associated with a lower risk for severe coronary artery disease. Black tea has also been associated with heart health. In one study oolong tea, a partially fermented tea, was specifically associated with lower blood sugar levels in type 2 diabetics.

Coffee. Coffee, like red wine, contains phenol, which helps prevent oxidation of LDL cholesterol. Studies are finding no association between coffee consumption and fatal or nonfatal heart disease even after 10 years. In fact, in one study the highest rates of fatal heart disease were in non-coffee drinkers, and women who increased their coffee intake reduced their mortality rates. On the downside, unfiltered coffee (Turkish coffee, Scandinavian boiled or French pressed coffee, and espresso) contains an alcohol called cafestol, which may raise cholesterol and triglyceride levels. Filtered coffee does not contain this residue. Coffee drinking is associated with small increases in blood pressure, but the risk it poses is very small in people with normal blood pressure. People with existing hypertension should avoid caffeine altogether.

Of note, caffeine has specific effects on insulin and glucose that may have an effect on people with diabetes, but the consequences are not clear. Some studies suggest that drinking large amounts of coffee may protect against diabetes. On the other hand, other research indicates that caffeine may increase the risk for insulin resistance. Some studies have reported a spike in insulin after drinking caffeinated beverages, which can be dramatic in people who are overweight. Research is needed to clarify the effects of caffeine on diabetes. In any case, caffeine intake can affect a person's awareness of hypoglycemia, since it reduces blood flow in the brain even in the presence of sufficient blood sugar. People with diabetes who drink even two or three cups of coffee may even believe they are hypoglycemic when their blood glucose levels are normal. On the positive side, coffee intake may increase awareness of hypoglycemia in some people who have difficulty recognizing its symptoms.

Weight Control for Type 2 Diabetes

Even modest weight loss can reduce the risk factors for heart disease and diabetes. There are many approaches to dieting and many claims for great success with various fad diets. They include calories restriction, low-fat/high-fiber, or high protein and fat/low carbohydrates. Some evidence suggests that people may respond differently to specific diets depending on whether their weight is overly distributed around the abdomen or not. According to a 2003 report comparing four major diets (Atkins, the Zone, Ornish, and Weight Watchers), any healthful diet that achieves weight loss helps the heart. To date, although many diets achieve effective immediate weight loss, none has emerged as an effective tool for maintaining healthy weight. [For more detailed information, see Well-Connected Report #53 Weight and Diet.]

The following are some basic approaches to dieting depending on the severity of the weight problem:

• The simplest (but still difficult) approach to weight loss is reducing calories and exercising at least 150 minutes a week, assuming there are no health problems to preclude it.
• Behavioral and mental changes in eating habits and attitudes about food and weight are also essential to weight management.
• For people who are very overweight and cannot lose weight using lifestyle measures, a number of effective weight-loss medications are available.
• And for those with severe obesity, surgical procedures are proving to be very beneficial.

Some Tips for Losing Weight. The following offer some general suggestions for dieters:

• Start with realistic goals. Diet failure is extremely common and the odds of significant weight loss are low, particularly in people with the highest weights. People who are able to restrict calories, engage in an exercise program, and obtain help in making behavioral changes can expect to lose between 5% and 10% of their current body weight--which is generally all that is needed to achieve meaningful health changes. Certainly, the unwholesome and distorted image of a super-thin female shape should not be anyone's goal. (Anorexia, obesity's alter ego, is far less common but is the other side of this dysfunctional aspect of our culture.)
• Maintain a regular exercise program, assuming no precluding health problems. Choose one that is enjoyable. Check with a physician about any health considerations. [For more information, see Well-Connected Report #29 Exercise.]
• Do not use hunger pangs as cues to eat. A stomach that has been stretched by large meals will continue to signal hunger for large amounts of food until its size reduces over time with smaller meals.
• Be honest about how much you eat and start by recording all calories in writing. Studies suggest that when many people report their own calories intake they significantly underestimate their consumption of high-calorie and over-estimate the low-calorie foods. People who do not carefully note everything they eat tend to take in excessive calories when they believe they are dieting.
• Observe weekend eating. People tend to eat more on the weekends. If it is difficult to monitor all meals during the week, it be may be useful to at least track eating habits during these days.
• Once the pound are lost, strive to maintain the healthier weight. Make daily, even hourly, conscious decisions about eating and exercising activities. Such thinking, in many cases, can become automatic and not painful.
• Don't give up, even after repeated weight loss failure. Most studies indicate that yo-yo dieting or weight cycling has no adverse psychological or physical effects. Repeated dieting also does not impair the body's ability to burn calories efficiently.
• Weight loss, in any case, should not be the only or even the primary goal for people concerned about their health. The success of weight reduction efforts should be evaluated according to improvements in chronic disease risk factors or symptoms and by the adoption of healthy lifestyle habits, not by just the number of pounds lost.

Calorie Restriction

Calorie restriction has been the cornerstone of obesity treatment. Restricting calories in such cases also appears to have beneficial effects on cholesterol levels, including reducing LDL and triglycerides and increasing HDL levels. In fact, in a study of an African community, inhabitants had very-low-calorie diets and favorable cholesterol levels in spite of a relatively high intake of saturated fats.

The standard dietary recommendations for losing weight are the following:

• As a rough rule of thumb, one pound of fat equals about 3,500 calories, so one could lose a pound a week by reducing daily caloric intake by about 500 calories a day. Naturally, the more severe the daily calorie restriction, the faster the weight loss. Very-low calorie diets have also been associated with better success, but extreme diets can have some serious health consequences. [See Box Warning on Extreme Diets.]
• To determine the daily calories requirements for specific individuals, multiply the number of pounds of ideal weight by 12 to 15 calories. The number of calories per pound depends on gender, age, and activity levels. For instance a 50-year old moderately active woman who wants to maintain a weight of 135 pounds and is mildly active might require only 12 calories per pound (1,620 calories a day). A 25-year old female athlete who wants to maintain the same weight might require 25 calories per pound (2,025 calories a day).
• Fat intake should be no more than 30% of total calories. Most fats should be in the form of monounsaturated fats (such as olive oil). Saturated fats (found in animal products) should be avoided.

Heart-Healthy Diets

Diet plays an important role in the health of the heart. There is no single diet that suits everyone, but at this time the Mediterranean diet appears to have the most favorable findings. Of note, weight control, quitting smoking, and exercise are essential companions of any diet program. [For detailed information, see Well-Connected Report #43 Heart Healthy Diet.]

Mediterranean Diet

The Mediterranean diet is rich in heart-healthy fiber and nutrients, including omega-3 fatty acids and antioxidants. Evidence now strongly indicates that this dietary approach may be the most important for protecting the heart and extending survival. The diet recommends the following:

• A relatively high fat intake (about 35% to 45% of daily calories, mostly in monounsaturated and polyunsaturated fats). The Mediterranean diet is known for its use of olive oil, but the greatest benefits found in a major study of this diet appeared to be derived from the use of canola oil, which is rich in omega-3 fatty acids. Olive oil, in fact, does not contain omega-3 fatty acids. On the other hand, olive oil may have beneficial effects independent from those on lipids, such as improving insulin and blood glucose levels and reducing blood pressure.
• Daily glass or two of wine.
• The same protein intake as the AHA, although fish is the primary source. (It avoids high-fat dairy and meat products.) In fact, one 2001 study suggested that fish-consumption, not wine, is the heart-protective ingredient in this diet.
• Lower carbohydrate intake than AHA. Emphasizes not only fresh fruits and vegetables, but also higher amounts of nuts, legumes, beans, and whole grains.
• Foods seasoned with garlic, onions, and herbs.

Therapeutic Lifestyle Changes (TLC) from the National Cholesterol Education Program

Guidelines in 2001 from the National Cholesterol Education Program include the following for preventing and managing high cholesterol levels in adults:

• Choose five or more servings of fresh fruits and vegetables and six or more servings of whole grains, legumes. Soluble fiber is preferred (from cereal grains, beans, peas, legumes, and many fruits and vegetables).
• Fats can be up to 35% of daily calories, but no more than 7% should be from saturated fat. (People with high triglycerides or low HDL or both may need a higher fat intake.) Choose fats containing unsaturated fatty acids (from vegetables, fish, legumes, and nuts). Choose margarines containing sterols or stanols (e.g., Benecol, Take Control). Avoid trans fatty acids found in commercial products as much as possible.
• Proteins choices should be limited in general to fat-free and low-fat milk products, fish, legumes, skinless poultry, and lean means.
• Limit cholesterol intake to less than 200 mg per day.
• Maintain healthy body weight and a healthy level of physical fitness.

The Ornish Program and Severely Fat-Restricted Diets

The Ornish program limits saturated fats as much as possible, reduces total fat to 10%, and increases carbohydrates to 75% of calories. It is a very effective but demanding regimen:

• It excludes all oils and animal products except nonfat yogurt, nonfat milk, and egg whites.
• Foods stressed are whole grains, legumes, and fresh fruits and vegetables.
• People in the program exercise 90 minutes at least three times a week.
• Stress reduction techniques are employed.
• People do not smoke nor do they drink more than two ounces of alcohol per day.

Everyone on low fat diets should consume a wide variety of foods and take a multivitamin if appropriate.

High-Protein Diets

High-protein diets, such as the Atkins and South Beach diets, are proving to be very effective in producing short-term weight loss. Because of their emphasis on fats and proteins, many experts are concerned about long-term health problems. Still, significant studies are reporting benefits on cholesterol and blood sugar levels. Centers that promote this approach argue that heart problems from obesity are due to insulin disturbances from sugar imbalances. Therefore, they believe that restricting carbohydrates is the best approach for obesity--and especially for overweight people with diabetes. More research is needed, however, to determine the long-term impact on health.

The DASH Diet

The DASH diet (Dietary Approaches to Stop Hypertension) is proving to help lower blood pressure after eight weeks. Restricting sodium improves results. The diet appears to have antioxidant effects and may even prove to be a good diet for lowering LDL cholesterol levels--although the beneficial HDL levels also decline.

This diet is not only rich in important nutrients and fiber but also includes foods that contain far more electrolytes, potassium, calcium, and magnesium, than are found in the average American diet. The dietary recommendations are as follows:

• Avoid saturated fat (although include calcium-rich dairy products that are no- or low-fat).
• When choosing fats, select monounsaturated oils, such as olive or canola oils. (One study reported a reduced need for anti-hypertension medication in people with a high intake of virgin olive oil, but not sunflower oil, a polyunsaturated fat.)
• Choose whole grains over white flour or pasta products.
• Choose fresh fruits and vegetables every day. In one 2002 study, people who increased their intake of fruits and vegetables experienced a drop in blood pressure after six months. Many of these foods are rich in potassium, fiber, or both which may help lower blood pressure.
• Include nuts, seeds, or legumes (dried beans or peas) daily.
• Choose modest amounts of protein (preferably fish, poultry, or soy products). Soy in combination with fiber-rich foods or supplements may have specific benefits. Oily fish may also be particularly beneficial. They contain omega-3 fatty acids, which have been associated with heart and nerve protection.

[For more information, see Well-Connected Report #14 High Blood Pressure.]

Diabetic Exchange Lists

The objective of the exchange lists is to maintain the proper balance of carbohydrates, proteins, and fats throughout the day. The exchange lists can be obtained by calling or writing to the American Diabetes Association. [See Resources.]

In developing a menu, patients must first establish with a doctor or dietitian their individual dietary requirements, particularly the optimal number of daily calories and the proportion of carbohydrates, fats, and protein. The exchange lists should then be used to set up menus for each day that fulfill these requirements.

The following are some general rules:

• The diabetic exchanges are six different lists of foods grouped according to similar calorie, carbohydrate, protein, and fat content; these are starch/bread, meat, vegetables, fruit, milk, and fat. A person is allowed a certain number of exchange choices from each food list per day.
• The amount and type of these exchanges are based on a number of factors, including the daily exercise program, timing of insulin injections, and whether or not an individual needs to lose weight or reduce cholesterol or blood pressure levels.
• Foods can be substituted for each other within an exchange list but not between lists even if they have the same calorie count.
• In all lists (except in the fruit list) choices can be doubled or tripled to supply a serving of certain foods. (For example 3 starch choices equal 1.5 cups of hot cereal or 3 meat choices equal a 3-ounce hamburger.)
• On the exchange lists, some foods are "free." These contain less than 20 calories per serving and can be eaten in any amount spread throughout the day unless a serving size is specified.

Exchange List Categories

The following are the categories given on the exchange lists:

Starches and Bread. Each exchange under starches and bread contains about 15 grams of carbohydrates, 3 grams of protein, and a trace of fat for a total of 80 calories. A general rule is that a half-cup of cooked cereal, grain, or pasta equals one exchange and one ounce of a bread product is one serving.

Meat and Cheese. The exchange groups for meat and cheese are categorized by lean meat and low fat substitutes, medium-fat meat and substitutes, and high-fat meat and substitutes. High fat exchanges should be used at a maximum of 3 times a week. Fat should be removed before cooking. Exchange sizes on the meat list are generally one ounce and based on cooked meats (three oz of cooked meat equals 4 oz of raw meat).

Vegetables. Exchanges for vegetables are 1/2 cup cooked, 1 cup raw, and 1/2 cup juice. Each group contains 5 grams of carbohydrates, 2 grams of protein, and between 2 to 3 grams of fiber. Vegetables can be fresh or frozen; canned vegetables are less desirable because they are often high in sodium. They should be steamed or microwaved without added fat.

Fruits and Sugar. Sugars are now included within the total carbohydrate count in the exchange lists. Sugars still should not be more than 10% of daily carbohydrates. Each exchange contains about 15 grams of carbohydrates for a total of 60 calories.

Milk and Substitutes. The milk and substitutes list is categorized by fat content similar to the meat list. A milk exchange is usually one cup or 8 oz. For those who are on weight-loss or low-cholesterol diets, the skim and very low-fat milk lists should be followed, and the whole milk group avoided. Others should use the whole milk list very sparingly. All people with diabetes should avoid artificially sweetened milks.

Fats. A fat exchange is usually 1 teaspoon but it may vary. People, of course, should avoid saturated and trans fatty acids and choose polyunsaturated or monounsaturated fats instead.

Exercise

Sedentary habits, especially TV watching, are associated with significantly higher risks for obesity and type 2- diabetes. Regular exercise, even of moderate intensity (such as brisk walking), improves insulin sensitivity and may play a significant role in preventing type 2 diabetes--regardless of weight loss. An important study reported a 58% lower risk for type 2 diabetes in adults who performed moderate exercise for as little as 2.5 hours a week.

In 2002, a well-conducted study on overweight adults confirmed previous research that reported beneficial changes in cholesterol and lipid levels, including lower LDL levels (the so-called bad cholesterol), even when people performed low amounts of moderate or high intensity exercise (e.g., walking or jogging 12 miles a week). However, more intense exercise is required to significantly change cholesterol levels, notably increasing HDL (the so-called good cholesterol). An example of such a program would be jogging about 20 miles a week. Such benefits in the study occurred even with very modest weight loss, suggesting that overweight people who have trouble losing pounds can still achieve considerable heart benefits by exercising.

Aerobic Exercises. Aerobic exercise is proving to have significant and particular benefits for people with both type 1 and type 2 diabetes. Regular aerobic exercise, even of moderate intensity, improves insulin sensitivity. People with diabetes are at particular risk for heart disease, so the heart protective effects of aerobic exercise are very important for this patient population. Moderate exercise, in fact, protects the heart in people with type 2 diabetes, even if they have no risk factors for heart disease other than diabetes itself. (In general, when exercising people with diabetes, should aim for a heart rate target of 55% to 75% of their maximum heart rate.)

Strength Training. Strength training, which increases muscle and reduces fat, may be particularly helpful for people with diabetes, but evidence is needed to confirm this.

Yoga. One study reported that yoga helped patients with type 2 diabetes reduce their need for oral medications.Studies have indicated that yoga and Tai Chi (an ancient Chinese exercise involving slow relaxing movements) may lower blood pressure almost as well as moderate-intensity aerobic exercises.

Some Precautions for People with Diabetes Who Exercise. The following are precautions for all people with diabetes, whether type 1 or 2:

• Because people with diabetes are at higher than average risk for heart disease, they should always check with their physicians before undertaking vigorous exercise. For best and fastest results, frequent high-intensity (not high-impact) exercises are best for people who are cleared by their physicians. For people who have been sedentary or have other medical problems, lower-intensity exercises are recommended using regimens designed with physicians.
• Strenuous strength training or high-impact exercise is not recommended for people with uncontrolled diabetes. Such exercises can strain weakened blood vessels in the eyes of patients with retinopathy. High-impact exercise may also injure blood vessels in the feet.

Patients who are taking medications that lower blood glucose, particularly insulin, should take special precautions before embarking on a workout program.

• Glucose levels swing dramatically during exercise; people with diabetes should monitor their levels carefully before, during, and after workouts.
• Patients should probably avoid exercise if glucose levels are above 300 mg/dl or under 100 mg/dl.
• To avoid hypoglycemia, diabetics should inject insulin in sites away from the muscles they use the most during exercise.
• They should also drink plenty of fluids. Before exercising, they should also avoid alcohol, which increases the risk of hypoglycemia.
• Insulin-dependent athletes may need to decrease insulin doses or take in more carbohydrates prior to exercise but may need to take an extra dose of insulin after exercise. Stress hormones released during exercise may increase blood glucose levels; in non-diabetics insulin is released to control this. The diabetic, therefore, needs to test their blood sugar and take an extra dose as instructed by their diabetes healthcare provider.
• Anyone with existing hypertension should discuss an exercise program with their physician. Before starting to exercise, people with moderate to severe hypertension should lower their pressure and be able to control it with medications. They should avoid caffeinated beverages, which increase heart rate, the workload of the heart, and blood pressure during physical activity. Everyone, and especially people with high blood pressure, should breath as normally as possible through each exercise. Holding the breath increases blood pressure.
• Good, protective footwear is essential to help avoid injuries and wounds in the feet.

[For more detailed information, see Well-Connected Report #29 Exercise.]

Stress Reduction

Chronic stress has been associated with the development of insulin-resistance, a condition in which the body is unable to use insulin effectively to regulate glucose (blood sugar). Insulin-resistance is a primary factor in diabetes. Stress can also exacerbate existing diabetes by impairing the patient's ability to manage the disease effectively.

[For recommendations on stress reduction, see Well-Connected Report #31 Stress.]

Resources

• www.diabetes.org -- American Diabetes Association
• www.niddk.nih.gov -- National Institute of Diabetes, Digestive, Kidney Diseases
• www.jdrf.org -- Juvenile Diabetes Research Foundation
• www.eatright.org -- American Dietetic Association
• www.nal.usda.gov/fnic -- Food and Nutrition Information Center
• www.childrenwithdiabetes.com -- Children with Diabetes dietary page
• www.mendosa.com/gilists.htm -- Glycemic index of a number of foods, including commercial cereals
• www.gourmetconnection.com/diabetic -- Diabetic Gourmet Magazine

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