Chapter 4.3.pdf

Chapter 5 – Part I Energy, Macronutrient, Fiber and Water Requirements during Pregnancy Energy - Recap EER BMR TEE PAL = TEE/BEE or BEE x PAL = TEE Recommended PAL: 1.6 – 1.7 Active 60 min/d moderate intensity (walking 4 mph) Converted to PA coefficient for EER calculation Estimated Energy Requireme...

Chapter 5 – Part I Energy, Macronutrient, Fiber and Water Requirements during Pregnancy Energy - Recap EER BMR TEE PAL = TEE/BEE or BEE x PAL = TEE Recommended PAL: 1.6 – 1.7 Active 60 min/d moderate intensity (walking 4 mph) Converted to PA coefficient for EER calculation Estimated Energy Requirement During Pregnancy ↑ BEE = one of major components of ↑energy requirements during pregnancy ↑ BEE due to: Metabolic contribution of the uterus and fetus ↑ work of heart and lungs Estimated Energy Requirement during Pregnancy Fat free mass (FFM) = strongest predictor of BEE FFM in pregnancy is comprised of ↑ Blood volume  Skeletal muscle mass  Fetal and uterine tissues Low energy-requiring Moderate energy-requiring  High energy-requiring Estimated Energy Requirement During Pregnancy Late pregnancy: ~ ½ of the increment in energy expenditure can be attributed to the fetus Fetus uses 56 kcak/kg body weight/day For a 3-kg fetus = 168 kcal/day Theoretical Energy Cost of Tissue Deposition During Pregnancy Total Energy Expenditure (TEE) in Pregnancy Steady decrease in PAL as pregnancy advances PAL = TEE/BEE ↑BEE (denominator) EER Calculation in Pregnancy in 1st Trimester EER equation for nonpregnant active women aged 19+ years is used in 1st trimester → EER (kcal/d) = 710.25 – (7.01 × age in y) + (6.54 × height in cm) + (12.34 × weight in kg). Energy Cost of Tissue Deposition Based on Recommended Rates of Weight Gain active level during pregnancy recommended bc outcomes are better usually (less complications) EER for Pregnancy EER Calculation in Pregnancy in 2nd and 3rd Trimester OB: need to have gradual decrease of weight OB : if gains too much --> excessive BW, preeclampsia, trouble with blood glucose control, HTN UW: LBW EER equation for pregnant active women → EER (kcal/d) = –223.84 – (2.04 × age in y) + (13.23 × height in cm) + (8.15 × weight in kg) + (9.16 × gestation in wk) + increment for tissue deposition Increment = +300 [underweight] +200 [normal weight] +150 [overweight] –50 [obese] Protein - Recap Requirement determined by: N balance RDA = 0.8 g/kg/day Protein Requirements During Pregnancy Additional protein requirements during pregnancy based on: Support of growth of maternal and fetal tissues Maintenance of additional protein stores Protein Requirements During Pregnancy Protein requirements vary with each trimester due to differences in protein needs for: Growth will need + balance Maintenance of the additional total protein accretion that has accumulated at the end of each trimester Derivation of Protein Requirements During Pregnancy growth need to know principles behind it, not the actual values Protein RDA for Pregnancy Average total additional protein requirement (EAR) = 21 g protein/day (assuming average additional body weight gained over 40 weeks gestation = 16.0 kg) CV = SD/Mean x 100% 12 = SD/21 (EAR) x 100 SD = 12 x 21/100 = 2.5 g 2 SD = 2.5 x 2 = 5.0 g Requirement for protein deposition during pregnancy = 21 g + 2 SD (5.0 g) = 26 g protein/d RDA for pregnant woman = 25 g protein/d (rounded off to nearest 5 g) of additional protein 1.2 for 1st trimester 1.5 during 3rd one with aa oxidation way higher than 1.1 that we have now with N balance Protein Status During Pregnancy Protein and/or energy poor diet prior to or during pregnancy associated with ↑ risk of LBW Mothers that consume more daily servings of dairy products, meat & fish:↓risk of LBW infants The prepregnancy period is key to prepare for the demands of pregnancy Provision of protein & energy supplements for 5 – 7 mo, instead of < 2 mo before conception higher birth weight & greater birth length Birth weights of 11 children born to a poor woman in Montreal Fats - Recap Linoleic & α-linolenic acid compete for same desaturase enzymes  RATIO linoleic: α-linolenic acid in diet AI for n-6 PUFA and n-3 PUFA Higher for men then women bc bigger Lower for > 50 years bc E intake goes down based on median intakes AI for N-6 Fatty Acids during Pregnancy 14 – 18 years 13 g/day linoleic acid 19 – 30 years 13 g/day linoleic acid 31 – 50 years 13 g/day linoleic acid AI for N-3 Fatty Acids during Pregnancy slightly higher than non pregnant 14 – 18 years 1.4 g/day α-linolenic acid 19 – 30 years 1.4 g/day α-linolenic acid 31 – 50 years 1.4 g/day α-linolenic acid based on normal diet without restriction —> if restriction, will restrict FA —> LBW risk Principal EFA in Blood of LBW and Normal BW Infants if not met: high risk of LBW Fatty Acid 20:4 n-6 Birth Weight (2500g) 16.7 ± 0.6* 22:6 n-3 6.5 ± 0.8 8.0 ± 0.5* 20:3 n-9 1.14 ± 0.1 0.6 ± 0.02* Crawford et al. (1992) Proportions of AA in Cord Plasma & Artery Phospholipids of Vegetarian (Filled Bars) & Omnivore (Hatched Bars) Term Infants Sanders, 1999 Proportions of DHA in Cord Plasma & Artery Phospholipids of Vegetarian (Filled Bars) & Omnivore (Hatched Bars) Term Infants Sanders, 1999 Carbohydrates - Recap Minimal amount of CHO required: determined by brain’s requirement for glucose ~ 110 – 140 g/d Without using glucose from protein or TG Without a rise in ketones EAR = 100 g CHO; CV = 15% RDA = 130 g CHO/d Carbohydrate Requirement during Pregnancy ↑ Metabolic rate  ↑ fuel requirement due to: 1. 2. Establishment of placental-fetal unit ↑ Energy supply for growth & development of fetus ↑ Need for metabolic fuel also includes: 1. 2. ↑ Maternal storage of fat EARLY in pregnancy; Energy to sustain growth of fetus during the last trimester Adaptation to pregnancy: 1. 2. 3. ↓ Fasting maternal blood [glucose] Development of insulin resistance Tendency to developing ketosis Carbohydrate Requirement during Pregnancy ↑ Mean respiratory quotient (RQ) for BMR & total 24 h energy expenditure  ↑ Glucose utilization by maternal-fetal unit Glucose transfer from mother to fetus ~ 17 – 26 g/d in late gestation Carbohydrate Requirement during Pregnancy Newborns: glucose oxidation ~70% of estimated brain’s fuel req. Fetal brain can clearly utilize ketoacids ↑Ketoacids common in pregnant women If non-glucose sources supply 30% of fuel req. of the fetal brain, brain glucose utilization rate = 23 g (32.5 g x 0.70) daily Same as the average maternal-fetal glucose transfer rate (mean 22 g, range 17 to 26 g) Fetal brain utilizes essentially all glucose derived from the mother Carbohydrate Requirement during Pregnancy To assure the fetal brain with glucose (~33 g/d) independent of utilization of ketoacids, EAR for CHO = EAR for nonpregnant women (100 g/d) + additional amount req. during the last trimester (35 g/d) = 135 g/day No evidence to indicate that a certain portion be consumed as starch or sugar RDA: CV = 15% based on variation in brain glucose utilization RDA = EAR + 2SD = 130% of EAR Carbohydrate Requirement during Pregnancy EAR for Pregnancy 14 – 18 years 19 – 30 years 31 – 50 years 135 g/day of carbohydrate 135 g/day of carbohydrate 135 g/day of carbohydrate RDA for Pregnancy 14 – 18 years 175 g/day of carbohydrate 19 – 30 years 175 g/day of carbohydrate 31 – 50 years 175 g/day of carbohydrate Fiber - Recap Total fiber = Dietary Fiber + Functional Fiber For heart health: 14 g Dietary Fiber/1,000 kcal, particularly from cereals = Fiber AI Dietary Fiber and Pregnancy No evidence that beneficial effect of fiber is different from nonpregnant women  AI = 28 g/d (14 g/1000 kcal x 1978 kcal) Dietary Fiber AI for Pregnancy 14- 18 years 28 g/day of Total Fiber 19 – 30 years 28 g/day of Total Fiber 31 – 50 years 28 g/day of Total Fiber Water - Recap Largest single constituent of the human body Thirst is not well correlated with fluid needs Hydration status assessed by plasma/serum osmolality AI for water to prevent acute effects of dehydration Large variations in water needs  no EAR Water AI for Pregnancy Median daily intake of drinking & beverage water during gestation = 2.3 L Intake of water from food = 0.6 L Total intake ~2.9 L AI for water for pregnant women 14 – 50 yrs = 3.0 L/d total water