39 - Diabetes Flashcards
What is diabetes?
A group of metabolic disorders characterized by hyperglycemia, resulting from defects in insulin secretion, insulin action or both
What is the effect of diabetes?
This causes abnormalities in the metabolism of carbohydrates, protein and fat
What are the short term complications of diabetes?
Short-term complications: keto-acidosis, hyperosmolarity, lactic acidosis
What are the effects of chronic hyperglycemia?
Chronic hyperglycemia causes long-term damage to eyes, kidneys, nerves, heart and blood vessels
Describe the statistics of diabetes in the US
- 29.1 million Americans (9.3% of population)
- 8.1 million are undiagnosed
- 1.7 million new diagnoses/year
- 86 million Americans had prediabetes
- Americans 65+: 25.9% or 11.8 million seniors
- Seventh leading cause of death
- Comorbid conditions: hypertension, dyslipidemia, CVD, stroke, eye disease, kidney disease, amputations
Describe type 1 diabetes
- Immune mediated or idiopathic destruction of the β-cells of the pancreas
- 5-10% of those with diabetes
- Rate of destruction of β-cells can vary
- Causes an absolute lack of insulin
Describe type 2 diabetes
- Insulin resistance AND/OR
- Relative insulin deficiency
- 90-95% of those with diabetes
What are the diagnostic criteria of diabetes?
** KNOW THIS **
Fasting plasma glucose > 126 mg/dl after an overnight 8 hour fast*
- OR -
Random plasma glucose > 200 mg/dl with classic symptoms of diabetes mellitus (e.g. increased thirst or urination, or unexplained weight loss) or a hyperglycemic crisis
- OR -
Plasma glucose > 200g/dl 2 hours after a 75 g oral glucose load*
- OR -
Hemoglobin A1c level > 6.5%*
Describe obesity and insulin resistance
- Idea that insulin resistance was cause of Type 2 diabetes was proposed in 1930s
- Failure of target organs to respond normally to insulin—don’t take up/use glucose for energy
- Contributing factors: genetics, aging, central obesity, sedentary lifestyle, high fat diet, medications
- Excess nutrient intake leads to adipocyte enlargement and inflammatory response
- Increased levels of free fatty acids inhibit glycolysis—persistent hyperglycemia
Describe the hormonal regulation of blood glucose via insulin
Insulin increases…
- Glucose uptake in muscle and adipose tissue
- Amino acid uptake and protein synthesis
- Fatty acid synthesis and esterification
- Glycogen synthesis
- Glycolysis
Insulin decreases…
- Blood glucose levels
- Gluconeogenesis
- Lipolysis
- Proteolysis
What are the stimulators and repressors of insulin secretion?
Simulators
- Increased blood glucose
- Increased amino acids
- Increased fatty acids
- Incretin hormones
- Acetylcholine
Repressors
- Leptin
- Sympathetic nervous System (via α2-adrenergic agonists, such as norepinephrine)
Describe hormonal regulation of blood glucose via glucagon
Glucagon increases... - Breakdown of glycogen (glycogenolysis) - Lipolysis (activates hormone-sensitive lipase) - Gluconeogenesis ketogenesis
Glucagon decreases…
- Synthesis of glycolytic enzymes
- Rate of glycolysis
- Glycogen synthesis
What are the stimulators and repressors of glucagon?
Stimulators of glucagon…
- Low blood glucose
- Increased circulating amino acids
- Sympathetic nervous system (via α2-adrenergic agonists, such as norepinephrine
Repressors of glucagon…
- Hyperglycemia
- Increased circulating fatty acids
- Somatostatin
Describe regulation of blood glucose by epinephrine
- Secreted by adrenal medulla in response to acute stress
- Increases glycogen breakdown
- Increases gluconeogenesis from lactate and amino acids
- Increases mobilization of fat via activation of hormone sensitive lipase
- Acts on α and β receptors
Describe the regulation of blood glucose by cortisol
- Produced by adrenal cortex in response to stress, trauma and hypoglycemia
- Works synergistically with glucagon to actvate key gluconeogenesis enzymes
- Indirectly maintains glucose production from protein and facilitates fat metabolism
Describe the well fed state in the body
** KNOW THIS **
- Insulin secretion increases
- Absorbed nutrients are utilized and stored
- Breakdown of stored nutrients suppressed
Describe the fasting state in the body
** KNOW THIS **
- Glucose levels fall
- Stored energy sources are mobilized
- Insulin secretion falls, glucagon activity rises
Describe primary prevention of diabetes
Diabetes prevention program
- Large RCTs tested if lifestyle modification slows or prevents progression towards diabetes
- This was based on the China Da Qing diabetes prevention study and the Finnish diabetes study
These addressed the question: If you address adiposity will you address type 2 diabetes?
What is the takeaway?
I’m not going to test on this, but just know that
- lifestyle modification found to be more effective than metformin in reducing incidence of diabetes
- others
What are the goals of nutrition and lifestyle?
Individualize goals with each patient
General goals
- Hemoglobin A1c40 mg/dL (men)/>50 mg/dL (women)
- Achieve and maintain body weight goals
Patient education and frequent contact with team (dietician, certified diabetes educators, physicians)—key to deliver improvements
What should your diabetic patients eat?
- Key component of diet for general population and persons with diabetes
- Amount and type of carbohydrates consumed impact blood glucose levels
Describe the glycemic index
- A measure of how quickly a food causes our blood sugar levels to rise; ranks food on a scale of 0-100
- These are based on measures taken while eating 50 grams of selected food, by itself, on an empty stomach
Describe food high on the glycemic index
Foods high on the GI are quickly digested or absorbed (processed carbohydrates)
Describe food low on the glycemic index
Foods low on the GI are more slowly digested and absorbed; often contain fiber, protein or fat and cause a slower rise in blood sugar
