NUTR - DIET & DIABETES Flashcards
Define DM (diabetes mellitus)
a metabolic disorder characterized by hyperglycemia (high blood sugar) resulting from either the DEFICIENCY IN INSULIN SECRETION (Type I) or POOR CELLULAR RESPONSE TO INSULIN (Type 2)
Classical symptoms of diabetes
- polyuria (frequency urination)
- polydipsia (increased thirst)
- polyphagia (increased hunger)
Outline the types of diabetes
- Type 1 –> body can’t produce insulin, requires injections
- Type 2 –> cells fail to use insulin properly (insulin resistance); can be combined with an absolute insulin deficiency
- Gestational diabetes –> pregnant women who have never had diabetes before have high blood glucose during pregnancy
- Maturity-Onset Diabetes of the Young (MODY) –> a monogenic or Mendelian form of diabetes, depending on a single gene mutation and independent from lifestyle
What are Type I & Type II diabetes also called?
Type I - insulin dependent (also juvenile)
Type II - non-insulin-dependent
Outline the main causes of Type I diabetes.
- loss of insulin-producing beta cells in the pancreas
- can be further classified as auto-immune
- beta cell loss is due to a T-cell mediated autoimmune attack, resulting in low or no insulin secretion
- there is NO known preventative measure against Type I diabetes (~ 10% of cases)
Outline the main causes of Type II diabetes.
- insulin resistance (IR) which may be combined with initially high insulin secretion & then reduced insulin secretion as the pancreas deteriorates
- this is a defective responsiveness of body tissues to insulin
- one cause is believed to involve the cellular insulin RECEPTOR
- ~ 90% of cases
- Early stages = reduced insulin sensitivity; hyperglycemia can be reversed
Distinguish between the causes of Type I & Type II diabetes
- Type I is partly inherited & then triggered by certain (usually viral) infections (which is environmental)
- Type II is due mainly to lifestyle factors (diet, exercise, smoking), overlaying genetic predisposition
- In Type I, the HLA genotypes are responsible for this onset. HLA system is a gene complex encoding the MHC proteins in humans; These cell-surface proteins are responsible for the
regulation of the immune system in human - In Type II, some individuals have more genetic predisposition to insulin resistance (IR) than others
Outline 4 criteria used to diagnose DM
- fasting plasma glucose level >/- 7.0 mmol/L
- plasma glucose >/- 11.1 mmol/L 2 hours after a 75 g oral glycose load as in a glucose tolerance test (OGTT)
- Casual plasma glucose >/- 11.1 mmol/L
- Glycated hemoglobin (HbA1C) >/- 6.5%
Contrast between Type I & Type II diabetes.
T1: sudden onset, T2: gradual
T1: any age, T2: mostly in adults
T1: thin or normal, T2: often obese
T1: concordance in identical twins = 50%, T2 = 90%
T1: autoantibodies usually present; T2: absent
What is glycated haemoglobin (HbA1c)
- a form of hemoglobin measured by doctors to identify average plasma glucose concentrations over prolonged periods of time
How is HbA1c formed?
- formed by hemoglobin’s exposure to plasma glucose (some glucose bonds to hemoglobin)
- As the average amount of plasma glucose increases, the fraction of glycated hemoglobin
increases in a predictable way. - over 2-3 months
List some complications of diabetes
- hyperglycemia damages retina of eyes (diabetic retinopathy) –> lead to blindness
- damage to kidneys (diabetic nephropathy)
- damage to nerves (diabetic neuropathy) - leading cause of foot wounds and ulcers
- gastric effects, respiratory effects
Diabetes management
- keeping blood sugar levels as close to normal as possible (euglycemia)
- Type II can be treated with oral medications (as well as insulin) - most common = metformin
- close dietary management, exercise, patient education, etc.
List the treatments of Type II diabetes.
(1) agents which increase the amount of insulin secreted by the pancreas,
(2) agents which increase the sensitivity of target organs to insulin (metformin)
(3) agents which decrease the rate at which glucose is absorbed from the gastrointestinal tract.
What are some risk factors for Type II diabetes?
- obesity (greater weight = higher risk of insulin resistance bc fat interferes with the body’s ability to use insulin)
- sedentary lifestyle (muscle cells have more insulin receptors than fat cells, so a person can decrease insulin resistance by exercising - being more active also lowers blood glucose levels by helping insulin to be more effective)
- unhealthy eating habits (too much fat, not enough fiber, too many high GI carbs)
- family history + genetics
- increased age (pancreas ages = doesn’t pump out insulin as efficiently; as cells age, they become more resistant to insulin)
- high blood pressure & high cholesterol - 2 key components in metabolic syndrome, they also damage heart vessels
- history of gestational diabetes (begins when hormones from placenta make mother insulin resistant
