5: Energy and protein Flashcards
Basal metabolic rate.
Minimum energy expenditure compatible with life.
Estimated energy requirement (EER) definition and criteria.
Average energy intake for a healthy person of a given gender, age, weight, height, and activity level, consistent with good health. Criteria is body weight within the healthy range and in a non-growth state.
Basal energy expenditure.
Kcal/24 hrs measured in the sedentary supine position.
Total energy expenditure (TEE)
Energy spent, on average, in a 24 hr period by an individual or a group of individuals.
Physical activity level (PAL)
TEE/BEE. Used only for adults and non pregnant non lactating women.
Sedentary (in terms of PAL)
Only the physical activity level that is required for independent living.
What is the strongest predictor of BEE?
Fat-free mass (FFM).
Why does BEE increase during pregnancy?
Metabolic contributions of the fetal placental unit + uterus, increase work of the heart and lungs, increased FFM (blood volume, skeletal mass, and fetal/uterine tissue).
What increase in energy is required by just the fetus, on average, over the whole pregnancy? Does the rate change through the pregnancy?
56 kcal/kg body weight/day. By the end of the pregnancy the fetus accounts for half of the increment of increased energy demands. Much higher than the beginning of the pregnancy.
What is the average energy deposition during pregnancy? Does it vary?
Average is 41,518 kcal. Can be closer to 60,726 in lower BMIs and in very high BMIs can be -324.
Why does PAL decrease during pregnancy?
Primarily due to increase in BEE (PAL= TEE/BEE).
What is the median increase in TEE during pregnancy?
8 kcal/gestational week. Ex 2nd trimester 169 kcal, 3rd trimester 272 kcal to keep up with increase in TEE.
How many calories can be attributed to energy deposition per day throughout pregnancy?
180 kcal/day
How much protein is needed per day on average? What is this amount compensating for?
50 g/day, because constant degradation and synthesis of protein is not 100% efficient and starts to deplete.
Does the rate of protein synthesis change throughout the life cycle?
In g/kg/day rate different in newborns (17.4), infants (6.9), adults (3), elderly (1.9)
What accounts for the additional protein requirements in pregnancy?
Supporting growth of fetal and maternal tissue and maintenance of additional protein stores (important in latter pregnancy)
What is the RDA for protein for pregnant women?
35 g/day in additional to the 0.8 g/kg/day
What indicators are used to estimate protein RDA?
Nitrogen equilibrium
Are the recommendations for alpha linolenic acid and linoleic acid RDA or AI? What is the significance of that?
AI. This is just the median intake associated with good health outcomes, so not perfect.
What is the carbohydrate RDA based on?
The minimum amount of glucose required by the brain without needing to use fat or protein as an energy source.
Histidine
Indispensable. Higher requirements in infants.
Alanine
Dispensable.
Arginine
Conditional. Glutamine/glutamate and asparagus are precursors.
Aspartic acid
Dispensable
Isoleucine
Indispensable.
Leucine
Indispensable
Tyrosine
Conditional. Phenylalanine is precursor.
Serine
Dispensable
Tryptophan
Indispensable
Valine
Indispensable
Aspargine
Dispensable
Cysteine
Conditional. Methionine and serene precursors. Higher requirement for premature babies, inadequate rate of synthesis from methionine.
Proline
Conditional. Glutamate precursor.
Methionine
Indispensable
Phenylalanine
Indispensable
Glutamic acid
Dispensable
Lysine
Indispensable
Glycine
Conditional. Serene and choline precursors.
Glutamine
Conditional. Glutamic acid and ammonia precursors. Higher requirements in conditions of stress.
What does “conditionally indispensable” mean?
They are synthesized from other amino acids and/or their synthesis is limited under special pathophysiological conditions.
It is thought they probably only these five amino acids are truly dispensable to a neonate:
Alanine, aspartate, glutamate, serine, and probably asparagine
What are the two nitrogen pools?
All proteins in tissue and circulation, free amino acids dissolved in body fluids, from dietary intake, and de novo synthesis
How much protein in an adult human being is synthesized and degraded each day (on average)?
250 g protein.
What parts of pregnancy is protein stored? Mobilized?
Stored early, mobilized in second half.
