Week 8-9 Obesity + Diabetes Flashcards
BMI
Weight (lb)/ Height(in)^2
> Obesity: % of adults classified as 30+ BMI
> Increasing with diabetes and HTN
> People tend to overestimate height and underestimate weight (inaccuracy of up to 10%)
> NHANES: calculates obesity based on physical examination
> More prevalent in the South
Obesity (Overview)
Obese child –> 7.5x risk of adult obese
> 3/4 obese and 1/10 normal children –> obese
> Insulin resistance, Type II DM, fatty liver, atherosclerosis, HTN, stroke, CA, asthma, sleep apnea, neurodegeneration
> Cancer Risks: liver (men) and uterus (women): 27-Hydroxycholesterol (27HC) to high cholesterol and breast CA
Obesity and CA: DCA from microbes
- High-fat diet + genetics (host) –> obesity –> Primary bile acids converted to DCA via altered microbiota (gut) –> DNA damage, SASP and CA (liver)
- Inflammation from inactivity + obesity
> Adipocytes –> glucose (insulin resistance, Type II DM)
> Immune cells –> Atherosclerosis
> Brain cells –> AD, HD, PD
> Systemic increase in cytokine –> CA - Associated with high stroke rate (esp for 35+)
Stunkard Study: Genetic Determinants of Obesity
- 540 adult Danish adoptees in four weight class
- Statistical significance in correlation between weight class and BMI of biological parents (broad spectrum); no impact via family environment
- Pima People: SW USA have obesity onset around 50% and 95% of Pima with NIDDM are obese
> Arizona: BMI 33.4, DM 54% (M) and 37% (F)
> Mexico: BMI 24.9, DM 6% (M) and 11% (F)
Thrifty Gene Theory (Pima)
Thought to increase fitness and survival chances during famine (Variants selected)
> Affects storage, appetite, behavior, energy expenditure and response to macro/micro
> Obese: high metabolic disease risk and low microbial complexity
Environmental Determinants of Obesity
Increased food supply and decreased $/C
> 1970: 2250 kcal/day, 2000: 2800 kcal/day
> Close associations/friend groups can increase rate of obesity (unaffected by neighbor)
> Sources of sugar: Soda drinks, grain-based desserts, and fruit drinks (up 35% MI, 26% type II, weight gain risks)
> Prevention: more dietary fiber, fruits, veggies (plant-based)
Testing for Obesity
- Caliper skinfold test: body fat estimate (fat surrounds bone, skin and muscle)
- Underwater weighing
- Bod Pod: accurate body volume measurement
- Dexa (dual-energy X-Ray absorptiometry) scan: body composition
> Two waves reflected by lean muscle and bones –> maps body and takes composition - Waist circumference: visceral fat (between subcutaneous and retroperitoneal)
Visceral vs subcutaneous Obesity
Normal adiposity + energy-dense (high fat and sugar) + inactivity –> positive energy balance –>
- S. Obesity (healthy; no ectopic fat: low muscle/epicardial/liver fat)
- +Smoking, bad genetics, maladaptive response, stress –> visceral (dysfunctional; altered FFA met and adipokines release; lipid overflow-ectopic fat)
* * Visceral increases CVD, diabetes, breast/colon CA risks and metabolic syndromes (50mil+ US; risk factors are abd. obesity, high BGL, HTN, high LDL/low HDL, high inflammatory markers like C-reactive proteins)
Energy Expenditure (EE) Calculation
1. EE = basal metabolism + physical activity + TEF > Physical activity: 1.4-1.9*W > TEF (food thermic effect): 1.05-1.1W 2. Harris-Benedict Equation of RDEE > F: 655 + 9.6W + 1.85H - 4.7 *years > M: 66 + 13.7W + 5H - 6.8*years 2. Physics of body mass > Caloric input --MASS-> physical activity + basal
Diabetes (Overview)
- 1.5mil new cases among 18+ population
> 1/4 with DM (7.2 mil, 28%) don’t know they have it
> #1 cause of blindness, kidney failure and amputations (cause of death: CVD/MI/failure 2-8x higher for T2 DM)
> Associated with kidney disease, retinopathy, and vascular disease - Prediabetes: between abnormal level and T2DM
> 1/3 (84mil), 90% dunno
Diabetes Risk Factors
Normal: 42- mmol/mol, 6%-
PreD: 42-47, 6.0-6.4%
Diab: 48+, 6.5%+
- Age: higher with age (esp 65+)
- Excess weight: obese and overweight are significantly higher than normal weight
- Excess added sugar consumption:
> cross-sectional data shows 150 kcal/person/day increases sugar availability –> increase diabetes prevalence by 1.1%
> Glucose tolerance test: BGL in subjects after 75g of glucose intake; detection via HbA-1C (non-enzymatic modification/glycation of HbA + glucose)
> 126mg/dL+ fasting glu, 200+ 2hr glucose, 6.4%+ HbA1C - Excess fat and meat consumption
T1DM
Insulin-dependent
> 5-10% cases, B-cell loss (autoimmune), 8-12 y.o. onset
> Genetic predisposition –> normal insulin release –> glucose normal –> C-peptide loss eventually
> Treatment: lifelong insulin injection
> Symptoms: glucose monitor (single strip-based/wearable continuous; CGM detects dropping/increasing BGL), frequent urination/thirst, weight loss, ketoacidosis, impaired immune function (slow healing) and vascular system
> Identical twin: second’s risk is 1/2 (multiple gene)
T2DM/NIDDM
Non-insulin dependent
> 90% cases (80% are obese), reduced insulin sensitivity –> oversecretion of insulin, B-cell failure
> Treatment: medication and diet therapy (low GI food, 7% weight loss with 150 min of physical activity per week)
> Symptoms: initially normal BGL (pancreatic insulin compensates) –> B-cell death –> no insulin; CVD, microvascular problems; liver malfunction (excess glucose release when unneeded)
> NOT adult-onset: 3 y.o. with 7.2 HbA1C and high BMI
> Identical twin: second’s risk is 3/4 (multiple gene)
Diabetic Alert Dogs (DAD) and T2DM Medication
- Significant decreases in frequency of moderate-severe hypoglycemia and glycosylated hemoglobin lvl
- T2DM med:
> Lower liver glu prod: Metformin
> Lower insulin resistance: Avandia (Thiazolidinedione reduce glucose/FA by binding to peroxisome proliferator-activated receptors PPARy TFs; increases edema/MI risks by 130/30%)
> More insulin production: Sulfonylureas, Incretins (GLP-1/GIP increase insulin release and decrease glucagon release)
T2DM Bariatric Surgery
Decreases changes in glycated hemoglobin
> Intensive medical therapy, roux-en-Y gastric bypass, and sleeve gastrectomy
> Decreases risk by 80% over 15 years for obese patients
Dietary Trends Over time
- Key problems:
> excess weight and chronic disease - Key Barriers:
> Poor diet, excessive calories, physical inactivity - Science of 2015:
> Macronutrient in diet is unrelated to losing weight
> Not one macronutrient is more effective than any other
> Diets with 45-% calories as carbs are NOT better for long-term weight loss (12 months)
Mediterranean Diet
High vegetable, legumes, fruits, nuts, and whole grain intake (monosaturated FA, plant-based whole foods and fermented dairy)
> Contrast with standard western diet (red/processed meat, butter, high-fat dairy)
> Reduces coronary outcomes
> EPIC (Euro. prospective Investigation into Cancer/Nutrition) Study: Investigate importance of Med. Diet components in decreasing mortality
> 37% plant foods, 23% moderate alcohol intake, 17% low meat intake
EPIC Oxford: vegetarian vs non-vegetarian (Veg summary)
34% consumed vegetarian diet at baseline
> Secondary confounding factors can influence outcome of study
> Vegetarian diet is rich in phytochemicals/antioxidants, fiber, PUFA (W-6)
> Low in saturated FA, Na, B12/D, and PUFA (W-3)
> Reduced mortality (CVD/heart disease, all-cause), and incidences of CA and T2DM
> High levels of homocysteine
Lustig: Processed Food-An Experiment that Failed
Discussion Section
