Lecs-10510141019 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, and dairyMake up 2/3 of dietary protein in the US
What is most common dietary source of protein in the world?
Plant proteins: 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?
avg 90grams protein/day>High burden of disease
What are nutrients supplied by animal protein foods? Drawbacks?
> B vitamins, iron, zinc, calcium>But: low in fiber and can be high in fat
What are nutrients supplied by plant protein foods? Drawbacks?
> B vitamins, iron, zinc, calcium, FIBER >Less absorbable forms
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 amino acids in total: 9 essential and 11 non-essential
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?
one or more polypeptide chains (many AAs) folded into a three-dimensional shape
What determines a protein’s fxn?
Its shape determines its fxn
What is protein denaturation?
alteration in protein’s 3D structure>Results in: normal fxn ceases
What are causes of protein denaturation?
> Change in pH (e.g. digestion)>Heat (e.g. cooking)>Agitation (e.g. whipping an egg white)
What is AA structure?
Central carbon atom bound to an H atom –> Amino group (NH2) –> Acid group (C(O)OH) –> R Chain (differs by AA)
What is proteins structure?
> Peptide bonds: chemical bonds that link AA together>Dipeptide bonds: two AAs>Polypeptides: many AAs
How is protein digested and absorbed?
> Mouth – Mechanical breakdown via chewing>Stomach – HCL starts chemical digestion>Small intestine»_space;>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
Anaphylaxis
rapid, severe allergic rxn>Life-threatening>Epi-pen – epinephrine is used to treat allergic reactions
Amino Acid 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?
> 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>Transport proteins → move substances in and out of cells>Antibodies → immune system (antigens/foreign bodies)>Contractile proteins → help mscls move, E.g. Actin and myosin >Hormones → chemical messengers, E.g. insulin and glucagon>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»Two types: Kwashiorkor and Marasmus
What is Kwashiorkor?
pure protein deficiency>Characterized by swollen belly
What is Marasmus?
energy and protein deficiency>Wasting (same wasting you see w/ AIDS, cancer)>Characterized by depletion of fat stores and 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 calcium in urine»>High meat diet → excrete more Ca2+ in urine>Kidneystones>Increased risk of heart disease and cancer (red meat)>Increased body fat (excess protein not stored –> converted to fat)»>Anytime we have extra energy, our body converts it to fatty acids and stores in adipose tissue