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Carbohydrate-Controlled Diets for Diabetes Mellitus Chapter 21 Nutrition & Diet Therapy (7th Edition) I. Overview of Diabetes Mellitus • Incidence steadily increasing around the world – Many individuals are unaware they have disease – 6th leading cause of death in US – Contributes to other life-threatening conditions • Metabolic disorders characterized by elevated blood glucose concentrations & disordered insulin management Nutrition & Diet Therapy (7th Edition) Nutrition & Diet Therapy (7th Edition) Diagnosis of Diabetes • Based primarily on plasma glucose levels – Fasting or random samples – Glucose tolerance test • 50- to 75-gram glucose load ingested • Followed by blood glucose level measurements at certain intervals • Criteria for diagnosis – Random plasma glucose concentration ≥200 mg/dL (without regard to food intake) and classic symptoms present – Plasma glucose concentration ≥126 mg/dL after 8-hour fast – Plasma glucose concentration >200 mg/dL 2 hours after 75gram glucose load (used least) Nutrition & Diet Therapy (7th Edition) • Overt symptoms of hyperglycemia help confirm diagnosis— otherwise confirmed only if subsequent testing yields similar results • Prediabetes – Blood glucose levels between normal & diabetic • Fasting = 100-125 mg/dL • 2 hours after glucose load = 140-200 mg/dL – Individual is at risk for development of diabetes & cardiovascular diseases Types of Diabetes • • • • Diabetes Type 1 Autoimmune destruction of pancreatic beta cells – Insulin must be supplied exogenously (outside the body) – Inherited & environmental factors probably involved • • • Usually develops during childhood or adolescence – Symptoms appear abruptly – More gradual onset of symptoms in individuals who develop disease in later years Classic symptoms: polydipsia, polyuria, polyphagia & weight loss Ketoacidosis may be first sign • • • • Nutrition & Diet Therapy (7th Edition) Diabetes Type 2 Most common form of disease Often no symptoms Primary defect is insulin resistance: lower sensitivity to insulin in muscle, fat & liver cells – Pancreas secretes larger amounts of insulin to compensate— resulting in hyperinsulinemia – Gradually unable to compensate & relative insulin deficiency results Risk increased substantially by obesity, aging, physical inactivity Many cases remain undiagnosed More common in certain ethnic groups (Native Am., Hispanic, African, Asian, Pacific Islanders) Now, overweight children & adolescents, esp. those with family hx., are at risk of dev. Type 2 Nutrition & Diet Therapy (7th Edition) Acute Complications • Diabetic ketoacidosis in type 1 diabetes – Excess production of ketone bodies due to breakdown of TG & release of fatty acids into blood because CHO is not available • Acidosis results in lowered blood pH (<7.3) • Ketones spill into urine (ketonuria) – Blood glucose concentrations increase • Usually >250 mg/dL • May exceed 1000 mg/dL in severe cases Nutrition & Diet Therapy (7th Edition) Ketosis Acidosis Hyperglycemia – Other symptoms • • • • • Dehydration Hyperventilation Acetone breath Decreased BP Altered mental status (including diabetic coma) • Hyperosmolar hyperglycemic state in type 2 diabetes – Condition of severe hyperglycemia, usually in absence of significant ketosis – Slow onset—over several days or weeks – Symptoms include • Extreme hyperglycemia (levels in excess of 600 mg/dL) • Fluid losses, depleted blood volume & electrolyte imbalances • Neurological abnormalities • Coma – Often results from unrecognized thirst or inadequate fluid replacement Nutrition & Diet Therapy (7th Edition) • Hypoglycemia – Reduced blood sugar from inappropriate management of disease • • • • • Excess amounts of insulin or antidiabetic drugs Prolonged exercise Skipped or delayed meals Inadequate food intake Consuming alcohol without food • • • • • • Hunger Sweating Shakiness Heart palpitations Slurred speech Confusion – Occurs most often in type 1 diabetes – Symptoms Nutrition & Diet Therapy (7th Edition) Chronic Complications • Macrovascular complications – Accelerated development of atherosclerosis in the coronary arteries & those supplying the limbs – Cardiovascular diseases account for majority of deaths in diabetics – Type 2 diabetes associated with multiple risk factors for CAD • • • • Hypertension Abnormal blood lipids Obesity Increased tendency for clot formation & abnormal ventricle function – Other associated conditions with type 2 diabetes • Metabolic syndrome: cluster of symptoms associated with insulin resistance • Claudication (pain while walking) • Foot ulcers & gangrene Nutrition & Diet Therapy (7th Edition) Nutrition & Diet Therapy (7th Edition) • Microvascular complications – Progressive damage to microcirculation caused by long-term diabetes • Retinopathy (damage bl. vessels to the retina) • Nephropathy (damage bl vessels to the kidney) • Neuropathy – Nerve degeneration occurring in about 50% of diabetics – Contributes to development of foot ulcers, sexual dysfunction and delayed stomach emptying Nutrition & Diet Therapy (7th Edition) II. Treatment: Goals • Diabetes is chronic, progressive disease – Requires lifelong treatment – Management involves balancing meal planning, timing of medications, physical exercise • Primary goals – Establish good glycemic control – Reduce incidence of complications • Diabetes education is a major need for newly diagnosed patients & families – Provides knowledge & skills needed to implement treatment & manage disease – Certified Diabetes Educator (CDE) plays major role Nutrition & Diet Therapy (7th Edition) Nutrition & Diet Therapy (7th Edition) Evaluating Treatment • Most effective evaluation is through monitoring glycemic status – Self-monitoring of blood glucose • Provides feedback for adjustment of food intake, medications, physical activity • Helpful in prevention of hypoglycemia • Useful in both type 1 & type 2 diabetes • Frequency of monitoring depends on type of diabetes & specific needs of patient – Long-term glycemic control • Glycated hemoglobin (HbA1c) • Measures glycemic control during previous 2-3 months • Goal is to maintain HbA1c under 7% Nutrition & Diet Therapy (7th Edition) • Monitoring for longterm complications – – – – Blood pressure Lipid screening Urine protein checks Physical screening exams • Retinopathy • Neuropathy • Foot problems • Ketone testing – Checks for development of ketoacidosis • In presence of symptoms • In case of increased risk • Blood test more reliable than urine – Increased risk of ketoacidosis • Acute illness • Stress • Pregnancy Nutrition & Diet Therapy (7th Edition) Body Weight Concerns • Type 1 diabetes – Less likely to be overweight – Excessive gain often side effect of improved glycemic control – Weight concerns should not discourage intensive therapy – Intensive therapy associated with longer life expectancy & fewer complications – Important to ensure adequate energy intake for children—necessary for normal growth & development Nutrition & Diet Therapy (7th Edition) • Type 2 diabetes – Excessive weight can worsen insulin resistance • Weight loss recommended for overweight or obese • Moderate weight loss (10-20 lb) can improve glycemic control, blood lipid levels & BP – Low % IBW increases risk of morbidity & mortality Medical Nutrition Therapy: Nutrient Recommendations • Appropriate nutrition therapy can – Improve blood glucose levels – Slow progression of complications • Consider personal preference & lifestyle habits in planning • Modified to accommodate growth, lifestyle changes, aging, complications Nutrition & Diet Therapy (7th Edition) • Total carbohydrate intake – Has greatest influence on blood glucose levels after meal – Recommendation based on caloric needs & preference – Must be consistent at meals & snacks to reduce fluctuations in blood glucose between meals – Restriction of carbohydrate intake to <130 grams/day not recommended Nutrition & Diet Therapy (7th Edition) • Carbohydrate sources – Different carbohydraterich foods have different effects on blood glucose--glycemic effect – Influenced by fiber content, preparation method, other foods in meal, individual tolerance – Glycemic index (GI): ranking of carbohydrate foods based on glycemic effect • Fiber – Recommendations similar to those of general population • Include fiber-rich foods: legumes, whole grains, fruits, and vegetables. • 21-38 grams/day • Sugars – – – – Moderate consumption does not affect glycemic control Recommendations similar to general population Count sugars as part of daily carbohydrate allowance Artificial sugars can be used as substitute • Dietary fat – Guidelines similar to individuals at risk—control saturated fat (to < 7percent of total calories), trans fat & cholesterol intake Nutrition & Diet Therapy (7th Edition) • Protein – Guidelines similar to those for general population: 15-20% of total kcal – Some studies indicate benefits of higher protein intake • • • • Improve glycemic control Increase satiety Help weight loss Long-term effects unknown – High intakes discouraged because of renal effects • Alcohol use – Use in moderation: 1 women/2 men drinks/day – Interferes with glucose production in liver, causing hypoglycemia – Consume food when using alcohol • Micronutrients – Recommendations same as general population – Vitamin & mineral supplements not recommended unless deficiencies develop Nutrition & Diet Therapy (7th Edition) Medical Nutrition Therapy: Meal-Planning Strategies • Carbohydrate counting • Control carbohydrate intake & portion sizes • Regular eating pattern • Space carbohydrate intake evenly throughout day • Coordinate insulin injections with meals; adjust dosages to carbohydrate intake Nutrition & Diet Therapy (7th Edition) – Simpler & more flexible than other menu-planning approaches – Daily carbohydrate allowance based on individual energy & nutrient needs – Consistent carbohydrate intake needed to match medication or insulin regimen • Exchange lists – More complex than carbohydrate counting – Foods sorted according to proportions of carbohydrate, protein, fat – More structured dietary plan Nutrition & Diet Therapy (7th Edition) Nutrition & Diet Therapy (7th Edition) Necessary when insulin production does not meet metabolic needs • Insulin preparations – Differ by • Onset of activity • Timing of peak activity • Duration of effects – Classifications • • • • Rapid-acting Short-acting Intermediate-acting Long-acting Nutrition & Diet Therapy (7th Edition) Insulin Therapy • Insulin delivery – Usually administered by self-injection • Individual syringes • Injection ports • Insulin pump – Insulin is protein— would be digested if ingested orally Nutrition & Diet Therapy (7th Edition) Nutrition & Diet Therapy (7th Edition) • Insulin regimen: type 1 diabetes – Best managed with intensive insulin therapy • Use of intermediate or long-acting preparation to meet basal insulin needs • Rapid or short-acting preparation prior to meals • Multiple daily injections or use of insulin pump – Requires accurate determination of amount of insulin to inject prior to meal—based on • • • • Premeal blood glucose Carbohydrate content of meal Individual’s body weight & sensitivity to insulin Careful records needed to analyze carbohydrate-toinsulin ratio for individual Nutrition & Diet Therapy (7th Edition) Nutrition & Diet Therapy (7th Edition) • Insulin regimen: type 2 diabetes – Approximately 30% of type 2 diabetics require insulin therapy • Initially may achieve control with diet, physical activity & oral antidiabetic medications • Progressive disease ipancreatic function & may result in need for insulin to achieve glycemic control – Variety of regimens • Insulin therapy only • Combination of insulin with oral antidiabetic medications • Dosages & timing adjusted according to blood glucose levels Nutrition & Diet Therapy (7th Edition) • Insulin therapy & hypoglycemia – Most common complication of insulin treatment, especially intensive insulin therapy – Attempts to attain nearnormal blood glucose levels increases risk of over treatment – Corrected with immediate intake of glucose or carbohydrate-containing food • 15-20 grams of carbohydrate relieves hypoglycemia in about 15 minutes • Retest blood glucose level Nutrition & Diet Therapy (7th Edition) • Fasting hyperglycemia-3 causes: – Insufficient insulin, with decreasing action during night – Dawn phenomenon: increase in morning blood glucose due to early morning secretion of growth hormone – Rebound hyperglycemia: result of nighttime hypoglycemia—hormonal responses stimulate glucose production – Treated by insulin dosage or formulation adjustment Oral Antidiabetic Agents • Used to treat type 2 diabetes • Actions – – – – Improve insulin secretion Reduce glucose production in liver Improve use of glucose by tissues Delay carbohydrate absorption • Regimens – Monotherapy: use of single medication – Combination therapy: utilization of several mechanisms at one time • Achieves more rapid & sustained glycemic control • Dietary modifications & physical activity still required Nutrition & Diet Therapy (7th Edition) Nutrition & Diet Therapy (7th Edition) Physical Activity & Diabetes Management • Central feature of diabetes management – Substantially improves glycemic control – Improves insulin sensitivity, reducing insulin requirements • Regular aerobic & resistance exercise recommended – At least 150 minutes of moderate intensity activity and/or – 90 minutes of vigorous activity per week – Resistance program that targets all major muscle groups 3 times/week Nutrition & Diet Therapy (7th Edition) • Careful adjustment of food intake & insulin therapy to prevent hypoglycemia – Monitoring blood glucose levels before (if ,100mg/dl, CHO before activity) & after activity – Additional carbohydrates may be needed with prolonged activity – Avoid exercise if glucose levels are elevated (>250mg/dl) • Type 2 diabetics need medical evaluation before starting exercise program – Mild to moderate exercise initially – Proper hydration necessary before & during exercise Sick-Day Management • Illness, injury or infection result in hormonal changes that increase blood glucose levels – In type 1 diabetes, risk of diabetic ketoacidosis increases (hormonal changes h bl glu) – Some carbohydrate necessary to avoid ketosis—150-200 grams carbohydrate recommended – Routine monitoring of blood glucose & urine ketones – Monitor fluid intake to prevent dehydration Nutrition & Diet Therapy (7th Edition) III. Diabetes In Pregnancy Pregnancy in Type 1 or Type 2 Diabetes • Diabetes presents challenges during pregnancy • Preconception care is necessary to avoid complications of poorly controlled diabetes – Hormonal changes increase insulin resistance & requirements – Diabetes increases health risks for both mother & fetus • • • • Increased rate of miscarriage Higher than normal incidence of birth defects & fetal death Respiratory & metabolic problems in newborn Large-birthweight infants (macrosomia) • Glycemic control – At conception & during 1st trimester: reduces risks of birth defects & spontaneous abortion – During 2nd & 3rd trimesters: minimizes risks of macrosomia & morbidity in newborns Nutrition & Diet Therapy (7th Edition) Gestational Diabetes • Risk factors – – – – Family history Obesity Specific ethnic groups Previous delivery of infant >9 lb • Part of routine testing at 24-28 weeks gestation (GTT) – High-risk women screened prior to or soon after conception – Mild hyperglycemia increases risk to developing fetus & complications during pregnancy • Adjustment of energy intake necessary – Adequate energy needed for fetal development – Overweight or obese women may need modest kcalorie reduction (30% less than total energy needs-believe it or not) – Restricting carbohydrates to 40-45% of total energy can improve blood glucose levels after meals (iCHO in am) • Combine energy intake adjustment with regular activity • Insulin if poor bl glu control; no OHA, could be toxic to fetus Nutrition & Diet Therapy (7th Edition) IV. Nutrition in PracticeGlycemic Index • In diabetes treatment—total amount of carbohydrate more important than type of carbohydrate consumed • Glycemic index: measure of how quickly the carbohydrate in a food is digested & absorbed Nutrition & Diet Therapy (7th Edition) • Factors influencing glycemic effect – Starch structure (straight chain vs. branched chain) – Fiber content – Presence of fat & protein – Food processing – Mixture of foods in a meal – Individual glucose tolerance • • The lower the Glycemic Index the lower the blood glucose Nutrition & Diet Therapy (7th Edition) • Low-GI diet & chronic disease – Some research suggests low-GI diets may have positive effect on: • Diabetes prevention • Heart disease risk • Appetite & weight loss – Research largely inconclusive Nutrition & Diet Therapy (7th Edition) • Demonstrated benefits of low-GI diets – Beneficial if nutrient-dense, high-fiber foods – Can be useful tool in selection of healthful food from a food group – Often wholesome foods that have been minimally processed • Current recommendations of nutrition scientists – Consume a plant-based diet containing minimally processed grains, legumes, vegetables, fruits – Include abundant fiber & limited amounts of fats & sugars Nutrition & Diet Therapy (7th Edition)