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why energy requirement increase during pregnancy

- An increase in BMR is one of the major components to the increase in energy requirement during pregnancy.

- The increase in BMR is due to (1) the metabolic contributions of the uterus and fetus, and (2) the increase in work of the lungs and heart.

- Fat-free mass (FFM) is the strongest predictor of BMR, as fat mass is not metabolically active.

- In pregnancy, the FFM is comprised of:

o An increase in blood volume (low energy-requiring)

o Skeletal muscle mass (moderate energy-requiring)

o Fetal and uterine tissues (high energy-requiring, which is the major reason causing the raise in BMR)


how much energy is used by the fetus of energy added to the diet during late pregnancy

half of increment in energy expenditure


how much kcal fetus uses per kg of body weight per day

56 kcal/kg

a 3 kg burns 168 kcal per day


The additional energy requirements of pregnancy include

  • (1) the energy required to provide for the growth of tissues, and (2) the energy required for the maintenance of new tissue.
  • The new tissue includes the products of conception (fetus, placenta, amniotic fluid), and the increased maternal tissues (uterus, breasts, blood).


the energy cost of new tissue deposition may be calcualted from

  • from the amount of protein and fat deposited throughout the pregnancy.


what is recommended PAL

•1.6 – 1.7


•60 min/d moderate intensity (walking 4 mph)

•Converted to PA coefficient for EER calculation


what is low energy, moderate and high energy -requiring tissues expenditure in fetus

•FFM in pregnancy is comprised of

•↑ Blood volume -> Low energy-requiring

•Skeletal muscle mass ->   Moderate energy-requiring

•Fetal and uterine tissues  ->  High energy-requiring


how much energy is needed to gain 1 g of protein and 1 g of fat

5.6 kcal/g for pro and 9.5 kcal/g for fat


how much kcal is deposited every day during pregnancy and was it similar to theoreical value calculation

180 kcal/day,

  • The estimated energy deposition from this study was similar to the theoretical energy cost of tissue deposition analyzed previously.


What happens to PAL during pregnancy

  • There is a steady decrease in PAL as pregnancy advances.
    • PAL = TEE/BMR

During pregnancy, there is an increase in BMR, causing a decrease in PAL


median increase of TEE throughout pregnancy is

8 kcal/per gest.week


EER during pregnancy is the sum of

The EER during pregnancy is the sum of the (1) TEE of the woman in a non-pregnant state, (2) the median change in TEE of 8 kilocalories/week, and (3) the energy deposition of 180 kilocalories/day


when enrgy should be added in food durign pregnancy

  • During the first trimester, there is little weight gain and variation in TEE.
    • The additional energy required is solely acknowledged as of the second trimester.
  • The first trimester occurs from weeks 1 to 12, the second trimester from weeks 13 to 27, and the third trimester from week 28 to birth.
  • 8 kilocalories per week is multiplied by the midpoint week during the second trimester (week 20), and the midpoint week for the third trimester (week 34) to avoid over- and underestimations.


why pregnant women need more protein

  • The additional protein requirements for pregnancy are based on (1) the support in growth of maternal and fetal tissues, and (2) for the maintenance of additional protein stores.


when protein requirements for pregnant women increase

  • Protein requirements vary with each trimester due to differences in protein needs for growth, and maintenance of the additional total protein accretion that has accumulated by the end of each trimester.
    • The estimate of protein requirements is based on the growth and body composition at the end of each trimester, which assures an adequate protein intake to support growth throughout gestation.
  • As the total weight gain by the end of each trimester increases with the duration of pregnancy, the additional protein intake required to maintain the increased body weight increases as well.
    • There is low deposition of tissue during the first trimester, and, thus, there is NO increase in protein requirement during the first trimester.


what is the requirement for protein in women

  • The protein needed for new tissue to growth and the protein needed for the maintenance of new tissue during pregnancy is additional to non-pregnant protein requirements.
    • The additional pregnancy protein requirement during the second and third trimesters are averaged to devise the EAR for protein during pregnancy.
  • The average total additional protein requirement (EAR) is 21 grams of protein per day, assuming the average additional body weight gain over 40 weeks of gestation is 16.0 kg.
    • The RDA for pregnant women is 25 grams of protein per day of additional protein.


what mothers have decreased risk of low borth weight infants (what products)

  • A protein and/or energy poor diet prior to, or during pregnancy, is associated with an increased risk of low-birth weight.
  • Mothers that eat more servings of dairy products, meat, and fish are at a decreased risk of low-birth weight infants.
  • The pre-pregnancy period is key to prepare for the demands of pregnancy.


how much in advance women should prepare for pregnancy

  • Provision of protein and energy supplements for 5 to 7 months, instead of 2 months before conception, provide higher birth weight and greater birth length.


why omega 6 are important in pregnant women and what is requirement

  • Omega-6 fatty acids are incorporated into placental tissue and fetus and must be obtained from the maternal tissues or through dietary intake.
  • The AI is based on median linoleic acid intake of pregnant women, in which there is a lack of evidence for deficiency. There is a lack of information to determine an EAR.


Omega-3 FAs during pregnancy

  • The demand for omega-3 fatty acids must be obtained from the maternal tissues or through dietary intake.
  • The AI is used to determine the requirement for omega-3 fatty acids.


Principal EFA in Blood of Low-Birth Weight and Normal Birth Weight Infants

  • A study measured essential fatty acid content in maternal blood and fetal cord blood indicated that there are higher levels of ETA (omega-9 fatty acid), and lower levels of arachidonic acid (omega-6 fatty acid) and DHA (omega-3 fatty acid) in low-birth weight infants.
  • High levels of ETA indicate an essential fatty acid deficiency.
    • If there is a lack of both omega-6 and omega-3 fatty acids, desaturase enzymes produce omega-9 fatty acids, such as ETA, from oleic acid.


why vegetarians have higher risk of infants with cognitive developement problemes

  • Vegetarian diets provide an excessive omega-6 to omega-3 ratio due to high linoleic acid intake (e.g. 15:1, 20:1).
  • Adequate ratio of omega-6 to omega-3 range from 4:1 to 10:1.

Vegetarians have higher quantities of AA (arachidonic acid) and lower amounts of DHA, which could pose risk for brain development


why there is an increased metabolic rate in pregnancy 

  • Pregnancy induces an increase in metabolic rate due to an increased fuel requirement.
  1. The establishment of the placental-fetal unit
  2. An increase in the energy supply for the growth and development of the fetus
  3. An increased maternal storage of fat EARLY in pregnancy
  4. Energy to sustain the growth of the fetus during the last trimester


what adaptations happen during pregnancy in regards to CHO requirement

1.↓ Fasting maternal blood [glucose]

2.Development of insulin resistance

3.Tendency to developing ketosis


What hormones contribute to insulin resistance

Placental lactogen, estrogen, and progesterone


What is the role of Placental lactogen, estrogen, and progesterone in insulin resistance

  • Blunting of the action of insulin increases catabolism of maternal fat, glycogen, and protein to increase nutrient uptake by the fetus.
  • After consuming a meal, the blood sugar of the mother becomes particularly high, increasing the uptake of glucose by the placenta.

During the second half of pregnancy, there is an upregulation of glucose transporters on the fetal portion of the placenta, increasing the uptake of glucose


RQ during pregnancy is ____ for both BMR and 24-hour energy expenditure



what does it mean increase in glucose utilization by the maternal-fetal unit

  • Glucose oxidation may solely account for 70% of the estimated fetal brain's fuel requirement, which indicates that the fetal brain can clearly use keto acids. Conversely, there is commonly an increase in keto acids in pregnant women.
  • The glucose requirement in late gestation is 33 grams per day. Conversely, the amount of glucose that is transferred from the mother to the fetus is lower (17 to 26 grams per day) in late gestation.
  • If non-glucose sources supply 30% of the fuel requirement of the fetal brain, then the fetal brain glucose utilization rate is 23 grams per day.
  • These findings exhibit that the fetal brain utilizes essentially all the glucose derived from the mother


CHO requirement furing pregnancy is based on

  • The carbohydrate requirement during pregnancy is based on the transfer of an adequate supply of glucose to the fetal brain (33 grams per day) that is independent of the utilization of keto acids.
    • The EAR for carbohydrates is equal to the EAR for non-pregnant women (100 grams/day) with the rounded additional amount required during the last trimester (35 grams/day), which is equal to 135 grams/day.
    • CV=15%-> RDA=175 grams/day


Should CHO be consumed from some particular source?

•No evidence to indicate that a certain portion be consumed as starch or sugar