Lecture 8

true or false: protein deficiencies are rare in the U.S.

true

most of the world relies on ______ protein

plant

as a country’s economy improves, what happens to the source of protein?

the proportion of animal foods/proteins tend to increase

increased animal protein consumption also increases ______ _____ and _______ _____

total fat, saturated fat

the incidence of diabetes and obesity increases as _________ protein consumption increases

animal

animal products provide sources of protein, Bi vitamins, and what minerals?

iron, zinc, calcium

animal products are low in _______ and high in _______

fiber, fat

what is the difference between the sources of B vitamins, iron, zine, fiber, and phytochemicals available in plant protein compared to animal protein?

the forms of these vitamins and minerals are less absorbable in plant proteins than in animal proteins

when eating a vegan diet, what form of supplementation may be necessary?

B vitamin

amino acids

the building blocks of protein

what is the structure of amino acids?

central carbon atom bound to a hydrogen atom, an amino group, an acid group, and a side chain

essential amino acids

cannot be synthesized by the human body in sufficient amounts to meet needs

how do we obtain essential amino acids?

through our diet

easier to lack essential amino acids on what kind of diet?

plant-based diet

what happens if we don’t have all the essential amino acids?

we cannot synthesize protein

the only nutrient you consume that has nitrogen in it is…

protein and amino acids

when a non-essential amino acid is not available from the diet, what does the body do?

the body does a transamination reaction that transforms one amino acid into another

amino acids are linked by

peptide bonds

where are bonds formed between proteins?

between the acid group of one amino acid and the nitrogen group of the next amino acid

__________ bonds are formed between two amino acids

dipeptide

___________ are formed between many amino acids

polypeptide

a protein is made of one or more ________ chains _______ into a three-dimensional shape

polypeptide, folded

proteins must be _______ into a specific pattern

folded

folding of proteins is aided by

chaperon proteins

protein _______ determines function

structure

what is the shape of hemoglobin?

spherical

if the ______ of a protein is altered, its _______ may be disrupted

shape, function

normal hemoglobin disk shape allows them to ________ without problems

circulate

how does the sickle-shaped hemoglobin alter the function?

the sickle shape can cause hemoglobins to get stuck and reduce the ability of hemoglobin to distribute oxygen to muscles and the rest of the body

protein digestion starts where?

in the mouth as acids and enzymes breakup proteins into individual amino acids

how do amino acids get to the liver?

pass from the mucosal cell into the blood and to the liver and other parts of the body

true or false: we are inefficient at digesting protein and lots is lost in the feces

false

the body _________ synthesizes and breaks down protein

continuously

every protein is turned over every ____ days

30

________ is the major storage depots of protein

muscle

during periods of decreased protein intake what happens?

amnio acids borrowed from muscle are mobilized to provide amino acids for protein synthesis in vital organs

amino acids are also converted into ______ during periods of reduced energy and carbohydrate intake

glucose

proteins are put together in the

nucleus

transcription

DNA is copied into a molecule of mRNA

translation

the mRNA takes the genetic information from the nucleus to the ribosomes

at the ribosomes, tRNA reads the genetic code and delivers the needed amino acids to the ribosomes to form a polypeptide chain

the proportion of amino acids in the amino acid pool depends on what?

your diet

a shortage of amino acids limits the ability of the body to make

protein

proteins provide ________

structure

enzymes are proteins that speed up/slow down…

metabolic reactions

proteins serve as ________ in and out of cells

transportation

proteins help in ________ movement

muscle (contractile proteins)

a number of hormones are protein or peptide hormones such as

insulin and glucagon

proteins help regulate _____ and ______- base balance

fluid, acid

protein-energy malnutrition

a term that covers a range of protein deficiency conditions that may include only protein deficiency or protein deficiency plus energy deficiency

kwashiokor

pure protein deficiency; not enough available protein in the diet

marasmus

an energy and protein deficiency

true or false: there are instances of kwashiorkor and marasmus in the U.S.

false

how is the dietary protein requirement determined?

determined by nitrogen balance

how do you determine nitrogen balance?

total intake of protein - output (urine + fecal+ sweat+ misc)

how do we lose protein?

urine, fecal, sweat, skin cells

with a decreased energy intake, what happens to the amount of nitrogen lost?

increases (lose muscle)

if you increase your energy intake, what happens to the amount of nitrogen lost?

it decreases (you preserve muscle)

what is the RDA for protein?

0.8g x kilogram per body weight per day

the RDA is irrespective of _____ or ________ _____

age, activity, level

the RDA is _____ standard deviations above the requirement for protein?

two

what is the AMDR for protein?

10-35%

true or false: protein needs increase during periods of growth, pregnancy and lactation

true

when endurance athletes increase their oxidation when they run, some of their energy comes from…

protein and essential amino acids

3 months of adherence to a eucaloric diet providing protein RDA resulted in what?

significant reduction in thigh muscle cross-sectional area

why is the RDA not sufficient for older individuals?

reduced testosterone, growth hormone production decrease, insulin resistance, reduced activity levels

dietary protein may be a modifiable risk factor for _________ in older adults

sarcopenia

when you eat protein the rate of muscle protein synthesis _______

increases

essential amino acids are critical for the synthesis of new

protein

if you only give only essential amino acids (excluding nonessential amino acids) what happens?

you make as much protein as you would from a completely balanced protein

true or false: we can make all nonessential amino acids

true

the amount of essential amino acids in a protein determines what?

how much the percentage increase in protein synthesis is

_____ protein is the most complete protein, because it is the richest protein in essential amino acids

whey

BCAAs

branch chain amino acids

BCAAS need to be given in combination with

all EAAs

after you have a meal there is a _______ in the rate of protein synthesis and a ________ in the rate of breakdown

increase, decrease

when you stimulate the muscle the spike in protein synthesis is _______, and about the same decrease in the rate of breakdown

you see the greatest change in muscle protein synthesis when you eat protein _____ _______ lifting weights

right after

what is protein complementation?

combining plant proteins to create a combination of all the essential amino acids

when you eat above 20-30 grams of amino acids what happens?

everything eaten above that is oxidized

risk of amenorrhea increase with ______ volume of training

increased

amenorrhea

complete loss of menstrual cycle

what are the characteristics of women with amenorrhea?

low bone density and increased risk of osteoporosis

one theory is that when women achieve a specific body fat % they stop menstruating, but what did the study reveal?

there was no real difference in body weight and fat percentage but there was highly significant difference in bone density

why were amenorrheic the same weight and body fat percentage as the eumennorheic women?

they ate less food and they decreased their metabolic rate by eating less

amenorrheic women ate less of which macronutrient, despite athletes’ increased need of it?

protein

why is soy protein considered particularly effective for amennorhea athletes?

it has estrogen-like effects