Transcript Metabolism, Energy Balance & Body Composition

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)
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• 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
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Diabetes Type 1
Autoimmune destruction of
pancreatic beta cells
– Insulin must be supplied
exogenously (outside the body)
– Inherited & environmental factors
probably involved
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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
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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
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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
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Ketosis
Acidosis
Hyperglycemia
– Other symptoms
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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
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• Hypoglycemia
– Reduced blood sugar from inappropriate management of
disease
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Excess amounts of insulin or antidiabetic drugs
Prolonged exercise
Skipped or delayed meals
Inadequate food intake
Consuming alcohol without food
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Hunger
Sweating
Shakiness
Heart palpitations
Slurred speech
Confusion
– Occurs most often in type 1 diabetes
– Symptoms
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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
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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
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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
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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%
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• Monitoring for longterm complications
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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
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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
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• 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
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• 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
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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
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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
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Rapid-acting
Short-acting
Intermediate-acting
Long-acting
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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
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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
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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
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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
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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
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• 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)