Flashcards in Nutrition Modules 5 & 6: Diabetes Deck (100):
Where is amylase found? What is its function?
Saliva and small intestine (pancreas secretion)
Breaks down 1,4-glycosidic bonds to give glucose and maltose
What are the 3 brush-border enzymes?
What are the 3 monosaccharides absorbed by the small intestine? Through which transport mechanism?
1. Glucose: active transport
2. Galactose: active transport
3. Fructose: facilitated diffusion
Where are monosaccharides transported once absorbed by the small intestine? How? Why?
The liver via the portal vein to
3. Glycogen synthesis
What quantity of carbs can be absorbed by the small intestine in an hour?
Which cells in the small intestine absorb monosaccharides?
What are dietary fibers?
Plant polysaccharides that cannot be absorbed by small intestine
What are the 2 types of glucose protein carriers for entry into cells?
1. Energy dependent Na+/Glc co-transporters
Which GLUT is most widely expressed?
1. Erythrocytes and barrier tissues
2. Basal glucose transport: absorption
3. High affinity
1. Liver, pancreatic B-cells, small intestine, kidney
2. Transports all 3 monosaccharides and serves as the "glucose sensor"
3. Low affinity, high capacity
1. Testes and brain
2. Primary Glc transporter in neurons
3. High affinity for Glc and Gal
1. Adipose tissue, skeletal muscle, heart
2. Glucose uptake
3. High affinity when insulin present
1. Small intestine
2. Fructose transporter
3. High affinity for fructose
What are the 4 monosaccharide transporters of the small intestine?
1. Energy dependent Na+/Glc co-transporters
2. GLUT 1
3. GLUT 2
4. GLUT 5
When is the PPP stimulated?
When glucose is high
In which 4 organs/cells does the PPP happen?
3. Adipose tissue
4. Adrenal glands
What are the 3 types of precursors for gluconeogenesis?
3. Some AAs
In which 2 organs does gluconeogenesis occur?
What is the Cori cycle?
Gluconeogenesis in liver using the lactate produced in muscle because of anaerobic glycolysis
What % of glucose is recycled through the Cori cycle?
Describe glycogen synthesis.
1. G6P converted to G1P
2. G1P activated by UTP and added to existing glycogen by glycogen synthase
How is glycogen synthase activated?
How does glucagon stimulate glycogen breakdown? In which tissues?
1. Activates glycogen phosphorylase in muscles, liver, and kidney by phosphorylating it
2. Inhibits glycogen synthase by phosphorylating it
What are the 3 short-term complications of DM?
What are the 3 long-term complications of DM?
1. Microvascular: diabetic retinopathy, nephropathy
2. Macrovascular: peripheral, cerebrovascular, CVD
How is DM diagnosed?
1 of the following:
1. Random plasma glucose > 200 mg/dL + DM symptoms
2. FPG > 126 mg/dL*
3. PG > 200 mg/dL 2 hrs after 75g glucose load*
4. Hb A1C > 6.5%
* need to be repeated the next day
What % of DM cases are T1?
What % of DM cases are T2?
T1D peak onset?
T2D peak onset?
State of beta cells in T2D patients at diagnosis?
What 5 metabolic processes does insulin stimulate?
1. Glucose uptake
2. FA/TAG synthesis
3. Glycogen synthesis
4. AA uptake/protein synthesis
What 4 metabolic processes does insulin inhibit?
1. Glycogen breakdown
Describe the glucose uptake mechanism by GLUT 4 (3 steps)
1. Insulin/GLUT 4 dimerization
2. Autophosphorylation of receptor tyrosine kinase
3. Signaling cascase promoting glucose entry via GLUT 4 fusion with plasma membrane
Describe how chromium contributes to glucose uptake.
Chromium enhances the activity of tyrosine kinase by binding chromodulin, which then binds to the receptor => it enhances glucose uptake
What is the result of chromium deficiency?
Can increase chromium intake help T2D patients?
What 4 metabolic processes does glucagon stimulate?
1. Glycogen breakdown
What 2 metabolic processes does glucagon inhibit?
2. Glycogen synthesis
What kind of receptors does glucagon bind?
What 3 metabolic processes are stimulated by epinephrine?
How long after eating does the fasting state occur?
3-4 hours after
What are the 3 ways in which cortisol increases blood glucose levels?
1. Activates PEPCK to promote gluconeogenesis
2. Proteolysis to maintain gluconeogenesis from protein
3. Stimulates lipolysis
How does insulin stimulate glycogen synthesis?
1. Activates glycogen synthase by dephosphoralating it
2. Inhibits glycogen phosphorylase by dephosphoralating it
Does glucagon affect muscles?
What are the 9 populations at risk of T2D?
1. BMI >=25
2. First-degree relatives with DM (DIRECT FAMILY)
3. Birthed baby > 9 lbs
4. History of gestational diabetes
7. Physically inactive
8. Low HDL or high TAG
9. Impaired glucose tolerance
How often should high risk patients be tested?
Every 3 years
When should ALL patients be tested?
After 45 yo
Describe the obesity cycle of insulin resistance leading to T2D.
Obesity => high FAs => gluconeogenesis => hyperglycemia => increased insulin secretion => further weight gain => insulin can't secrete enough insulin => T2D
How can gestational diabetes affect the fetus? 2 options
2. Restricted fetal growth
What % of pregnancies are affected by gestational diabetes?
What are the 4 risk factors for gestational diabetes?
2. Family history of DM or GDM
4. Previous pregnancies with large babies
What is gestational diabetes due to?
Placental hormones interfere with maternal responsiveness to insulin
When is gestational diabetes diagnosed?
After the 1st trimester (24-28 weeks) at the first prenatal visit
What are the 3 parts of treatment for GDM?
1. Diet: caloric targets (less than 45% carbs), and dietician counseling
3. Insulin therapy if nutrition fails to maintain blood glucose OR if fetus is abnormally large (macrosomia)
How does exercise help diabetes patients? 2 parts
1. Increase muscle contractions = glucose uptake activation = insulin sensitivity increases = increase glucose uptake
2. Increase in catecholamines and glucagon increase gluconeogenesis and lipolysis (weight loss and better lipid profiles)
What kinds of questions should be avoided when assessing nutritional status of patients?
Leading questions (eg: what do you eat for breakfast, which assumes they eat breakfast) and questions about what was eaten the day before (focus on USUAL intake)
What is the downside of fat-free foods?
High in sugar
How should the 2h post-prandial glucose level be compared to the fasting glucose level?
What % weight loss is sufficient to control diabetes in T2D patients?
5-10% GRADUAL weight loss
What helps maintain glucose homeostatis?
Eintake = Erequirement
What is the normal fasting BG?
What is the normal 2h postprandial BG?
Below 140 mg/dL
How do fats and proteins ingested with carbs affect absorption?
They increase insulin so delay absorption
How long after eating do glucose levels peak?
An hour after
What are the 3 main factors that influence the glycemic response?
1. Individual variation
2. Carb source
3. Meal size/composition
What 6 carbs will lower the glycemic response?
1. Whole grains
2. Carbs with a high amylose/amylopectin ratio
3. Less cooked carbs
4. Less processed carbs
5. Reduced ripeness
6. Viscous fibers: gum, pectin
What kinds of foods will increase the glycemic response?
Insoluble (incompletely fermented) fibers: cellulose (wheat, vegetable skin), hemicellulose (corn kernel skin, brown rice), lignin (broccoli stems, seeds, nuts)
What is the glycemic index of a food?
Compares its quality to a reference 50g of sugar or white bread
What are 3 limitations of glycemic index?
1. Does not account for food condition (eg: ripeness)
2. Ignores other foods ingested
3. Fibers could be influencing results
Are complex carbs absorbed at the same rate as simple carbs?
How should DM patients ingest carbs?
Small amounts throughout the day
What are 4 symptoms of hypoglycemia I did not know about?
2. Blurry vision
3. Poor coordination
What are 3 potential causes of hypoglycemia?
1. Inadequate food intake
3. Excessive exercise
What is ketoacidosis caused by in DM patients?
Hyperglycemia but no insulin to trigger glucose uptake so ketone bodies are produced (same mechanism as starvation)
What do Hb A1C levels represent? How?
Average blood glucose over 2-3 months because glucose binds to Hb in RBCs in proportion to ambiant glucose and HbA1C (glycated RBC) remains in blood for the lifespan of the RBC
What is the KEY strategy to achieve glycemic control?
Monitor carb intake
What are the 2 types of symptoms associated with hyperglycemia?
1. Hyperosmolar symptoms
2. Impaired glucose uptake symptoms
What are the 4 hyperosmolar symptoms of hyperglycemia?
1. Polydipsia: excessive thirst
2. Polyuria: excessive peeing
3. Norturia: awakening to peeing
4. Sudden unexplained weight loss
What are the 5 symptoms of hyperglycemia due to impaired glucose uptake?
2. Poor wound healing
3. Chronic/recurrent skin infections
5. Neurological symptoms
What did the Diabetes Control and Complications Trial (DCCT) prove? With what patients?
Intensive management of T1D prevents complications:
1. Test blood glucose 4x/day
2. Insulin pump or injection 4x/day
3. Adjust insulin
4. Diet + exercise plan
5. See docs/monthly
What are the 3 goals of DM individualized nutrition therapy?
1. Improve lipid profile
2. Achieve/maintain ideal body weight
3. Adapt to culture and lifestyle preferences
Foods rich in what 3 things should be avoided by DM patients?
1. Saturated FAs
2. Trans FAs
What information is needed to calculate the daily carb requirement?
4. Physical activity
How many grams of carbs in 1 carb serving?
What are the 7 foods that have 0 carbs?
7. Salad greens (they have a little but not counted)
How does alcohol affect metabolism?
It inhibits gluconeogenesis by the liver
What are the 2 home glucose monitoring methods?
1. Finger stick
2. Urine ketones
How many calories should a DM patient burn each day exercising?
What is the target fasting BG for DM patients?
What is the target random BG for DM patients?
Below 180 mg/dL
What is the target HbA1C for DM patients?
What is the target HDL for DM patients?
> 50 mg/dL
What is the target LDL for DM patients?
Below 100 mg/dL
What is the target TAG for DM patients?
Below 150 mg/dL
What is the main measurable target for DM patients?
How often should HbA1C levels be tested?
What are the 5 glucose management tools?
1. Individualized meal plan
2. Self-monitoring blood glucose
3. Medical monitoring blood glucose
4. Medication as needed
5. Physical activity