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What is EER?
- Estimated energy requirement
- Represents the average dietary energy intake that will maintain energy balance in a healthy person of given gender, age, weight, height, and physical activity level consistent with good health
What does the EER take into account?
- Energy content of new body constituents during growth and pregnancy
- Milk produced during lactation
What is the criteria of EER?
Body weight is within the healthy range and should remain stable (in energy balance)
What is BMR?
- Basal metabolic rate
- The minimal rate of energy expenditure compatible with life
How is BMR measured?
Measured in the supine position under standard conditions of rest, fasting, immobility thermoneutrility and mental relaxation
What is TEE?
- Total energy expenditure
- The energy spent, on average, in a 24-hour period by an individual or a group of individuals
- Reflects the average amount of energy spent in a typical day, but is not the exact amount of energy spent each and every day
What is PAL?
- Physical activity level
- The ratio of TEE/BEE
- In adult men and non-pregnant, non-lactating women, BEExPAL=TWW or the daily energy requirement
What is the recommended PAL?
Why does the calculation of TEE for babies only depend on weight?
Because they are growing and developing
Why is the TEE increased with a greater weight and height?
The greater the weight and height, the more body mass that needs to be maintained with calories
For women 19 years and older, how ie EER calculated?
Why does the BEE increase during pregnancy?
Because the fetus needs energy
Why does the heart and lungs need to work harder when a woman is pregnant?
Needs more oxygen and since there is more mass, the heart needs to work harder
What is the strongest predictor of BEE?
- Fat free mass (FFM)
- Because adipose tissue is inactive metabolically
What is the FFM comprised of in pregnancy?
- Low energy-requiring expanded blood volume
- Moderate energy-requiring skeletal muscle mass
- High energy-requiring fetal and uterine tissues
How much energy does a fetus use?
56kcal/kg body wt/day
What part of pregnancy has the highest energy expenditure?
What happens if a woman diets during pregnancy?
If a woman diets during pregnancy it will compromise the growth of other tissues and have problems with the infant
How much of the energy expenditure can be attributed to the fetus during late pregnancy?
~1/2 the increment in energy expenditure
How much energy does a fetus need throughout the pregnancy?
56kcal/kg body wt/day
What is the total energy deposition between 14-37+ weeks of gestation based on?
- 3.7kg fat gain
- 925g protein
What happens if a woman goes into pregnancy with a high BMI?
They will use their fat supply to support pregnancy and do not need to gain as much weight
What happens if too much weight is gained during pregnancy?
- Preeclampsia (high blood pressure and protein in urine) and gestational diabetes can happen
- Risks to both themselves and offspring
What are some complications of high birth weight?
- Difficulties in delivery
- Poor glucose control
- Increased risk of infections
- Increased risk of chronic diseases later on in life
How does PAL change throughout the pregnancy?
- Steady decrease in PAL as pregnancy advances
- In the first trimester there is little change in pregnancy and weight
How does the median TEE vary throughout the pregnancy?
Median increase in TEE=8kcal/gestational week
How is EER during pregnancy calculated?
Sum of TEE in non-pregnant state+median change in TEE (8kcal/week)+energy deposition during pregnancy of 180kcal/day (new tissue deposition)
what is the acceptable distribution of macronutrients?
- 45-65% CHO
- 20-35% fat (25-40% for young children)
- 10-35% Protein
Which macronutrient is affected by the decrease in fat content for adults?
As fat lowers the percentage of protein increases, whereas the percentage of CHO remains the same through childhood and adulthood
Why is CHO levels unchanged from young childhood throughout adulthood?
To maintain enough glucose for optimal brian activity
What is a nitrogen balance study?
Measures how much protein a person takes in and it has to balance the amount that one excretes on a daily basis
How is protein loss measured?
In terms of nitrogen in urine and feces
What should the nitrogen balance be if a person is growing?
In growth, one needs a positive nitrogen balance (more intake than excrement) because there is retention of nitrogen to facilitate growth
What happens to the nitrogen balance during states of catabolic stress (surgery)?
There is not enough nitrogen coming in to balance what is going out (negative nitrogen balance)
Why do essential fatty acids have AI?
There is not enough information to determine EAR
What are the indispensable amino acids?
What are dispensable amino acids, and how many are there?
5- can be synthesized from either other a.a. or other complex nitrogenous metabolites
What are conditionally indispensable amino acids?
They are synthesized from other amino acids and/or their synthesis is limited under special pathophysiological conditions
Which amino acids are dispensable in the neonate?
only alanine, aspartate glutamate, serine and probably asparagine are truly dietarily dispensable
In what conditions must amino acids be obtained from a dietary source?
- Pathological states such as severe catabolic stress (limited capacity to produce glutamate)
What happens to amino acid metabolism in prematurity?
Inadequate rate at which cysteine can be produced form methionine
What are the 2 pools of amino acids?
- All proteins in tissues and circulation
- Free amino acids dissolved in body fluids
What is protein turnover?
Continual degradation and re-synthesis of these macromolecules
Is protein turnover efficient?
Protein turnover is not 100% efficient and can lead to losses of protein on a daily basis. These losses need to be recovered on a daily basis
Where do free amino acids come from?
Dietary intake and de novo synthesis
How much protein is synthesized and degraded in the adult human body?
upwards of 250g/day of protein
What is the median daily adult intake of protein?
How does the amount of protein turnover change throughout different life stages?
Daily amount of protein turned over is greater in infants and less in the elderly
Where does most of the protein turnover take place?
Liver and intestine contribute 50% of protein turnover
What is the largest single component of body protein mass?
Skeletal muscle (43%)
How much does skeletal muscle contribute to total protein turnover?
What is protein synthesis and degradation used for?
A sensitive means of regulating the amount of each enzyme or structural component
How is the quality of a protein source scored?
DRI developed a pattern to evaluate the quality of a protein source by the relative amounts of its amino acids
Do adults have low or high indispensable amino acid requirements?
Adults have very low indispensable amino acid requirements
What is the protein RDA for adults?
Why are there additional protein requirements during pregnancy?
- Support of growth of maternal and fetal tissues
- Maintenance of additional protein stores
Why do protein requirements vary with each trimester?
Due to differences in protein needs for growth and maintenance of total body protein that has accumulated
What is the protein RDA for pregnancy?
25g/day of additional protein
What is likely to occur if the mother has a protein and/or energy poor diet prior to or during pregnancy?
Low birth weight
What should mothers consume to reduce the risk of low birth weight?
Consume more daily servings of dairy products, meat and fish
During the pregnancy, when is protein stored, and when is it mobilized?
Protein is stored early in pregnancy and mobilized in the 2nd half of pregnancy
What is considered low birth weight?
Anything below 2.5kg