Exam 2 - Lecs 1-6 Flashcards
Is protein deficiency common in the US?
No, rare
What is most common dietary source of protein in US? How much of dietary protein does it comprise?
Animal sources—meat, poultry, seafood, eggs, dairy
>2/3
What is most common dietary source of protein in the world?
Plant sources—grains and veggies
What is the correlation btwn economic status and animal foods consumption?
W/ increase in economic status → increase in proportion of animal foods consumed
What is avg amount of protein consumed/day in US?
90g protein/day
>High burden of disease
What are nutrients supplied by animal protein foods? Drawbacks?
> B vitamins, iron, zinc, calcium
>Low in fiber, can be high in fat
What are nutrients supplied by plant protein foods? Drawbacks?
> Fiber, phytochemicals, and monounsaturated and polyunsaturated fats.
Less absorbable forms of protein and vitamins
What are amino acids (AAs)?
> Building blocks of protein
What are essential AAs?
AAs that can’t be synthesized by the human body in sufficient amounts to meet needs
>Need to include in diet
How many AAs in total? How many are essential vs. not?
20 AAs total—9 essential, 11 not
What are conditional essential AAs?
They need to be obtained via the diet when one is sick or in some conditions
What is unique about the 11 non-essential AAs?
We can convert all 11 non-essential AAs into one another
What is a protein?
1+ polypeptide chains (many AAs) folded into a 3D shape
What determines a protein’s fxn?
Its shape
What is protein denaturation?
alteration in protein’s 3D structure
>Normal fxn ceases
What are causes of protein denaturation?
> Change in pH (digestion)
Heat (cooking)
Agitation (whipping an egg white)
What is AA structure?
Central C bound to H, Amino group (NH2), Acid group (C(O)OH), R Chain (differs by AA)
What are peptide bonds, dipeptide bonds, and polypeptides?
> Peptide bonds—chemical bonds that link AA together
Dipeptide bonds—2 AAs
Polypeptides—many AAs
How is protein digested and absorbed?
> Mouth—Mechanical breakdown via chewing
Stomach—HCL starts chem digestion
Small intestine
»Active transport into mucosal cell, where dipeptides and tripeptides are broken down into single AAs
AA pass into blood, travel to liver
What causes food allergies?
Absorbing a protein whole = allergy
>Most common allergens = milk, eggs, nuts, wheat, soy, fish and shellfish, and peanuts
What is Anaphylaxis?
rapid, severe allergic rxn
>Life-threatening
>Epi-pen—epinephrine is used to treat allergic reactions
What is AA Pool?
We don’t store AA, but there are AAs floating in our blood from digestion and mscl breakdown (body proteins)
What are AAs used for?
> Energy,
Synthesis of glucose or fatty acids,
Synthesis of nonprotein molecules that contain nitrogen (e.g. DNA and RNA)
Protein Synthesis: Transcription and Translation
Nucleus (DNA to mRNA) ⇒ cytosol (mRNA to ribosomes) ⇒ ribosomes (tRNA reads code and synthesizes the protein)
What determines proportion of AAs in AA pool?
AA composition of the diet
What organ can excess protein consumption damage and why?
Kidneys bc we don’t store protein, we excrete it
What are some fxns of protein in the body?
> Enzymes → speed up metabolic rxns
Hormones → chemical messengers, E.g. insulin and glucagon
Antibodies → immune system (antigens/foreign bodies)
–
Transport proteins → move substances in and out of cells
Contractile proteins → help mscls move, E.g. Actin and myosin
Regulate fluid and acid-base balance
What is US and global impact of protein deficiency?
Not a problem in US but major cause of early mortality globally
What is Protein-Energy Malnutrition (PEM) and 2 types?
> Range of protein deficiency conditions
|»_space;Kwashiorkor and Marasmus
What is Kwashiorkor?
PURE protein deficiency
>Characterized by swollen belly
What is Marasmus?
energy AND protein deficiency
>Depletion of fat stores
>Wasting of mscl
Diets that contain animal protein can result in what?
consuming protein in excess of need
What are consequences of excess protein consumption over long periods of time?
> Hydration and kidney fxn issues
»From need to excrete excess Nitrogen
> Bone health issues from loss of Ca2+ in urine
»High meat diet → excrete more Ca2+ in urine
> ## Increased body fat (excess protein not stored –> converted to fatty acids –> stored in adipose tissue)Kidney stones
Increased risk of heart disease and cancer (red meat)
Why might red meat be related to an increased risk of chronic diseases?
> GRILLING (any high-dry/high-heat cooking) makes heterocyclic amines (HCA), which appear as blackened surfaces
»HCA is carcinogenic, acts like nicotine
> INCREASE IN BODY WEIGHT
»Associated w/ cancer risk, e.g. breast, colon, and prostate cancer
> Decrease in plant products
> Insulin secretion from essential AAs
»High lvls of Insulin can cause cell damage
> Arachidonic acid content (PUFA)
What is the implication of excess Nitrogen in the urine (N out > N in)?
Means you’re burning up body tissue (protein is seen as N in urine)
What is the implication of N in > N out?
Indicates tissue growth
How much protein do adults require by bodyweight?
0.8g/kg bodyweight
>Assumption: not excess body fat
When do we need more protein?
during periods of growth, pregnancy, and lactation
Do we need protein supplements?
> No – unregulated
Amino acid is brought to mscl right after exercise
»Need INSULIN to get AA into mscl
»Flavored milk is best to have after exercise
What is protein complementation?
Putting together foods to get all your amino acids, e.g. rice + beans
> Rice has a lot of Met + Cys but not Lys
Beans have a lot of Lys but not Met + Cys
Combine them and get enough of both
Why are we eating more as a population?
Portion Distortion – portions are larger = more cals
How is body weight assessed on popul’n lvl?
BMI = Weight in kg/ height in m2
>Tells whether overweight [BMI 25 – 29.9] or obese [BMI 30+]
Issues with BMI measurement?
> Does not measure fat
>Not useful for individuals but for popul’n measures
What is energy balance?
energy consumed equals energy expenditure
What constitutes an individual’s total energy expenditure?
Basal metabolic rate (BMR), physical activity, Thermic effect of food (TEF)
What’s Basal metabolic rate (BMR)?
energy you need to run your body, equals 60-75% of energy expenditure
>Varies by size, body composition, age, gender
What are 2 types physical activity?
> Daily, e.g. chores, walking, normal activity
>Strucutred, e.g. sports, gym
What’s the Thermic effect of food (TEF), aka diet-induced thermogenesis? What is Non-exercise activity thermogenesis (NEAT)?
> Energy used to digest/absorb food → inherent to food size
On avg = 10% of total energy in food, e.g. if you eat 100 cals you use 10 of those cals to digest food
We store more energy from smaller amounts of foods (why snacking causes weight gain)
> NEAT= Overeating and regulating body heat
When are body energy stores used or built?
> Weight loss = stores are used
>Weight gain= stores are built
Extra protein is stored as what?
FAT!
>Not stored as mscl or AA but as fat!
»»(converted to fatty acids and stored in adipose tissue)
What is the Hunger-Obesity Paradox?
Says that your chances of being overweight are higher if you’re
> Food insecure → associated w/ low-inc
Low-income
Low-education
Minority → associated w/ low-edu, low-inc
Define food insecure
For at least some part of the month you don’t know if you will have food at next meal
>Most of the time due to financial circumstances
What are reasons for the Hunger-Obesity Paradox?
> If you’re food insecure:
»You may overeat when food is available
»You may become more efficient at storing fat (survival)
»Erratic eating – you don’t consistently eat the same # of meals a day
> You’re going through feast and famine all the time
Increase activity of lipoprotein lipase? (theory)
What is passive overconsumption?
> When you keep eating a food, unaware you’re doing it
[taste, cost, convenience]
> Energy density—-calories for a weight/volume of food
»Higher energy density = high cals for low weight/volume food, e.g. refined grains (“white” pasta, rice, bread), products w/ added sugar/salt/fat-snack foods, candy
*LOWER COST → US gov’t subsidizes crops used to make high energy density foods
> > > Lower energy density: low cals for a low-weight/volume food, e.g. fruit, veggies, whole grains (have more water/fiber)
What are eating disorders?
Diagnostic and Statistical Manual (DSM) IV:
>Anorexia Nervosa (AN)
>Bulimia Nervosa (BN)
>Eating Disorder Not Otherwise Specified (EDNOS)
»>Binge Eating Disorder (BED)
About how many women struggle w/ an eating disorder or disordered eating in the U.S.?
1 in 5 women
What is DSM-IV diagnostic criterion for Anorexia Nervosa (AN)?
A. Refusal to maintain body weight at or above 85% of expected weight for age + height
B. Intense fear of gaining weight or becoming fat, even though underweight
C. Disturbance in the way in which one’s body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of seriousness of current low weight
D. (AMENORRHEA) In post postmenarcheal females: amenorrhea - the absence of at least 3 consecutive menstrual cycles
What are the 2 AN subtypes?
> Restricting types
>Binge-eating/purging type
Restricting Type
(AN subtype)
During current episode of AN, no regular binge eating or purging behavior
Binge-eating/purging type
(AN subtype)
During current episode of AN, regular binge eating or purging
> DIFFERENTIATED from bulimia bc of presence of a body weight
What is DSM-V diagnostic criterion for Anorexia Nervosa (AN)?
A. Persistent restriction of energy intake relative to reqs leading to a significantly low body weight in context of age, sex, developmental trajectory, and physical health
aa. ELIMINATES specificity of below 85% ideal body weight
B. Intense fear of gaining weight or becoming fat even though underweight
C. Disturbance in the way in which ones body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or the denial of the seriousness of the current low body weight
CHANGES in diagnostic criterion for Anorexia Nervosa (AN) from DSM-IV to DSM-V?
ELIMINATES objective weight criterion (specificity of below 85% ideal body weight), amenorrhea, and use of the word “refusal”