Nutrient Requirements During Lactation PDF

Chapter 5 – Part III Nutrient Requirements during Lactation Energy Requirements and Lactation Milk energy output computed from Milk production and Energy density of human milk  The stage and extent of breastfeeding affect the incremental energy requirements for lactation Energy Requirements and Lac...

Chapter 5 – Part III Nutrient Requirements during Lactation Energy Requirements and Lactation Milk energy output computed from Milk production and Energy density of human milk  The stage and extent of breastfeeding affect the incremental energy requirements for lactation Energy Requirements and Lactation Theoretically, energy cost of lactation could be met by ↓Time spent in physical activity or ↑Efficiency of performing routine tasks Early postpartum (PP) period: ↓ moderate and discretionary activities in most women Later: activity patterns highly variable Energy Requirements and Lactation Wt changes and energy mobilization from tissues: not in all lactating women In general, 1st 6 Mo PP: Mild, gradual wt loss 0.8 kg/Mo (average) Energy Requirements and Lactation American women mean milk production rates (term infants) 0 – 6 Mo: 0.80 L/day 7 – 12 Mo: 0.6 L/day 0.67 kcal/g milk Energy Requirements and Lactation Energy Requirements and Lactation 0.67 kcal/g milk  milk energy output = 0 – 6 Mo: 541 kcal/day ( 540 kcal/day) Maternal weight loss = 140 kcal/day 7 – 12 Mo: 381 kcal/day ( 380 kcal/day) Energy Requirements for 1st 6 Mo Lactation Energy Requirements for 2nd 6 Mo Lactation EER for Lactation 14 – 18 years EER = Adolescent EER + Milk energy output – Weight loss 0 – 6 Mo = Adolescent EER + [540 – 140 = 400] 7 – 12 Mo = Adolescent EER + 380 – 0 19 – 50 years EER = Adult EER + Milk energy output – Weight loss 0 – 6 Mo = adult EER + [540 – 140 = 400] 7 – 12 Mo = adult EER + 380 – 0 Protein and Lactation [Protein] in human milk not influenced by diet or body composition Need 1 g protein/kg body weight/day  Conservation of skeletal muscle in order to maintain good milk production Protein and Lactation Use factorial approach Assumed: Lactation process does not alter maintenance protein req. AND Protein and/or a.a. req. ↑ in proportion to milk production Protein and Lactation Human milk: ↑NPN ~ 20 – 27% of total milk N Urea: quantitatively important NPN component Diversion of urea loss from urine + some colonic fermentation to milk Assumed that part of ↑ N needs to produce milk NPN will come from dietary protein Factor 6.25 to convert NPN to protein Factorial Estimate of Increase in Protein Requirement Associated with Lactation Protein Requirements during Lactation EAR for Lactation – All age groups 1.05 g/kg/day of protein OR + 21.2 g/day additional protein Protein EAR for Lactation Non-lactating EAR = 0.66 protein/kg/d Req. for protein losses in milk = 21.2 g/d  57 kg (ref. woman) = +0.39 g protein/kg/d EAR for lactating woman = 0.66 + 0.39 = 1.05 g protein/kg/d or 57 kg x 1.05 = 60 g/day Protein RDA for Lactation Non-lactating RDA = 0.80 g/kg CV = 12% RDA = EAR + 24% or x 1.24 Req. for protein losses during lactation = 21.2 g/d x 1.24 = 26.3 g  + 25 g/day Per kg body wt:  57 kg (ref. woman) = + 0.44 g protein/kg/d RDA for lactating woman = 0.80 + 0.44 = 1.24 g protein/kg/d (or 1.1 after rounding off to lower 0.1 g) Protein Requirements in Lactation RDA for Lactation All age groups 1.1 g/kg/day of protein or + 25 g/day of additional protein N-6 Fatty Acids and Lactation N-6 Fatty Acids and Lactation AI for Lactation 14 – 18 years 13 g/day of linoleic acid 19 – 30 years 13 g/day of linoleic acid 31 – 50 years 13 g/day of linoleic acid N-3 Fatty Acids and Lactation Demand for secretion of n-3 PUFA in milk met by: N-3 PUFA from maternal tissues Through dietary intake N-3 Fatty Acids Lactating women: Lower plasma & RBC lipid DHA May reflect declining DHA status (inadequate intakes) OR Normal physiological responses to changes in Endocrine status Lipoprotein and lipid metabolism Nutrient transfer N-3 Fatty Acids and Lactation N-3 Fatty Acids and Lactation AI for Lactation 14 – 18 years 1.3 g/day of α-linolenic acid 19 – 30 years 1.3 g/day of α-linolenic acid 31 – 50 years 1.3 g/day of α-linolenic acid Carbohydrates and Lactation CHO requirement ↑during lactation Lactating women: ↑RQ & CHO utilization rates Preferential use of glucose by mammary gland Carbohydrates and Lactation Human milk lactose content ~ 74 g/L Changes very little Must ↑ precursors for lactose synthesis Need ↑ glucose from ingested CHO Or ↑ a.a.’s  prevent utilization of endogenous proteins for glucose production Carbohydrates and Lactation EAR for Lactation 14 – 18 years 19 – 30 years 31 – 50 years 160 g/day of carbohydrate 160 g/day of carbohydrate 160 g/day of carbohydrate RDA for Lactation 14 – 18 years 19 – 30 years 31 – 50 years 210 g/day of carbohydrate 210 g/day of carbohydrate 210 g/day of carbohydrate Carbohydrate Requirements Dietary Fiber AI 14 g/1,000 kcal x median energy intake Water Requirements and Lactation No evidence to suggest that renal function & hydration status are ≠ during lactation  Al for total water based on median total water intakes during lactation Water Requirements and Lactation AI for Lactation 14 – 18, 19 – 30 & 31 – 50 yrs = 3.8 L/day of total water Based on median intake Includes ~ 3.1 L (~ 13 cups) as total beverages, including drinking water Water Requirements and Lactation Another approach: Age (yrs): Non-pregnant water req. (L) + Water content of milk (L)* = 14 – 18 2.3 0.68 2.9 19 – 30 2.7 0.68 3.4 *Water content of average milk output (0 – 6 Mo) = 0.78 L milk x 87% = 0.68 L water 31 – 50 2.9 0.68 3.6 Potassium and Lactation Al for Lactation 14-18 years 2600 mg/day of potassium 19-30 years 2900 mg/day of potassium 31-50 years 2900 mg/day of potassium (Non-pregnant, non-lactating = 2300 mg/day 14-18 y; 2600 mg/day 19-50 y) Sodium and Chloride AI in Lactation  Small amount of Na secreted in human milk (0 – 6 Mo)  0.12 g/day (5.2 mmol/day)  Al for Na for lactating women = AI for non-lactating  Al for chloride = equimolar amount based on AI for Na Sodium and Chloride AI in Lactation Al for Sodium for Lactation 14-18 years 1.5 g (65 mmol) /day of sodium 19-30 years 31-50 years 1.5 g (65 mmol) /day of sodium 1.5 g (65 mmol) /day of sodium Al for Chloride for Lactation 14-18 years 23 g (65 mmol)/day of chloride 19-30 years 31-50 years 23 g (65 mmol) /day of chloride 23 g (65 mmol) /day of chloride Thiamin EAR for thiamin for lactating woman = 0.9 + 0.16 + 0.1 = 1.16 = 1.2 mg/d RDA = EAR + 2 x CV (10%) = 1.4 mg/d (Non-pregnant, non-lactating = 1.1 mg/d) Riboflavin Assume 0.3 mg/d riboflavin transferred to milk Daily milk production = 0.78 L Add 0.4 mg/d of riboflavin to EAR (0.9 mg/d)  EAR = 1.3 mg/d Riboflavin Assume riboflavin use for milk production = 70% efficient Adjust upward to 0.4 mg/d Add 0.4 mg/d to non-pregnant non-lactating EAR (0.9 mg/d) = 1.3 mg/d Riboflavin Assume CV = 10% RDA = EAR + 2 x CV = 1.6 mg/d (Non-pregnant, non-lactating = 1.1 mg/d) Niacin in Lactation ~ 1.4 mg/d preformed niacin secreted during lactation Add 1 mg to cover energy expenditure involved in milk production Need additional 2.4 mg/d of NEs NE bc can be synthesized from tryptophan Niacin EAR (11 mg) + 2.4 mg of NEs = EAR for lactation of 13.4 mg  13 mg/d CV = 15% RDA = 17 mg/d of NEs (Non-pregnant, non-lactating = 14 mg/d) Biotin AI ↑ by 5 μg/d – amount of biotin secreted in milk (AI = 35 μg/d) No distinction made for age or stage of lactation (Non-pregnant, non-lactating = 30 μg/d) Pantothenic Acid ↑ Intake of pantothenic acid  ↑ pantothenic acid content of milk Blood [pantothenic acid] lower at 6 wks and 3 Mo PP vs control women Pantothenic Acid No evidence that pantothenic acid intakes are inadequate during lactation Additional secretion in human milk (1.7 mg/d) ↓Maternal blood concentrations when intakes ~ 5 – 6 mg/d  AI = 7 mg/d of pantothenic acid recommended (Non-pregnant, non-lactating = 5 mg/d) (Non-pregnant, non-lactating = 5 mg/d) Vitamin B6 Additional req. for lactation >> amount secreted via lactation To ensure milk [B6] of 0.13 mg/L ~ 5 X this amount needed to be consumed + non-lactating EAR (1.1 mg/d) Vitamin B6 Add 0.6 mg of B6 to EAR (1.1 mg) for nonlactating women  EAR for lactation = 1.7 mg/d of B6 CV = 10%  RDA = 2.0 mg/d (Non-pregnant, non-lactating = 1.3 mg/d) Folate Av. daily amount of folate secreted in human milk ~ 85 μg/L 50% bioavailability of food folate Folate Calculation for extra folate: Milk volume x [folate] x bioavailability factor = 0.78 L x 85 μg/L x 2 = 133 μg/day Folate Non-lactating EAR (320 μg/day) + 133 μg/day = 450 μg/day of DFEs (rounded down) CV = 10%  RDA = 120% RDA = 500 μg/day (Non-pregnant, non-lactating = 400 μg/day) Vitamin B12 and Lactation Av. amount of B12 secreted in milk of mothers with adequate B12 status: 0 – 6 Mo: 0.33 μg/day 7 – 12 Mo: 0.25 μg/day Vitamin B12 and Lactation EAR for lactation = 2 μg/day (non-lactating EAR) + 0.33 μg/day = 2.4 μg/day (rounded up) CV = 10%  RDA = 2.8 μg/day (Non-pregnant, non-lactating = 2.4 μg/day) Choline and Lactation Need for choline is likely ↑during lactation Substantial amount secreted in human milk Mechanisms for conserving maternal choline status have not been identified ↑ AI during first 6 Mo. of lactation above non-pregnant, non-lactating AI Choline and Lactation Average milk volume = 0.78 L/day Average choline content of milk = 156 mg/L AI ↑ by 125 mg/day AI = 550 mg/day (Non-pregnant, non-lactating = 425 mg/day) Vitamin C EAR for lactation: Av. vitamin C produced in milk during first 6 Mo = 40 mg/d + EAR for non-lactating women RDA: CV = 10% Vitamin C EAR for Lactation 14 – 18 years 19 – 30 years 31 – 50 years 96 mg/day of vitamin C 100 mg/day of vitamin C 100 mg/day of vitamin C RDA for Lactation 14 – 18 years 19 – 30 years 31 – 50 years 115 mg/day of vitamin C 120 mg/day of vitamin C 120 mg/day of vitamin C (Non-pregnant, non-lactating = 75 mg/day) Vitamin A Human milk-fed infants: av. 400 μg/d of vitamin A (0 – 6 Mo) EAR for lactation = non-lactating EAR (500 μg) + 400 μg RAE/day  Assure adequate body stores of vitamin A Vitamin A big increase (almost double) requirements solely on retinol basis bc not enough evidence on carotenoids EAR for Lactation 14-18 years 885 μg RAE/day of vitamin A 19-30 years 900 μg RAE/day of vitamin A 31-50 years 900 μg RAE/day of vitamin A RDA for Lactation 14-18 years 1,200 μg RAE/day of vitamin A 19-30 years 1,300 μg RAE/day of vitamin A 31-50 years 1,300 μg RAE/day of vitamin A (Non-pregnant, non-lactating = 700 μg/day) Vitamin D Small quantities of maternal circulating vitamin D & metabolites  human milk Min. vitamin D intake to sustain serum [25(OH)D] in normal range during lactation is unclear No evidence that lactation ↑mother's RDA for vitamin D When sunlight exposure is inadequate  RDA of 15.0 μg (600 IU)/day needed (Non-pregnant, non-lactating = 600 IU/day) Vitamin E Av. amount of α-tocopherol in human milk (0 – 6 Mo) = 4 mg/d EAR for lactation = EAR for non-lactating woman 12 mg/d + 4 mg/d (CV = 10%) = 16 mg/day of α-tocopherol > Reported median intake for lactating women - 8.4 mg/d Estimates of vitamin E intake are underreported Vitamin E deficiency in breastfed infants: extremely rare  Supplements are unnecessary during lactation Vitamin E RDA for Lactation 14-18 years 19 mg/day of α-tocopherol 19-30 years 19 mg/day of α-tocopherol 31-50 years 19 mg/day of α-tocopherol (Non-pregnant, non-lactating = 15 mg/day) Vitamin K Vitamin K status of lactating women ≈ non-lactating women Treatment of mothers with pharmacological doses of vitamin K ↑ Phylloquinone content in maternal milk Typical diet Little effect on phylloquinone content in maternal milk Vitamin K not sig. secreted in milk  no evidence that AI for lactating women ≠ non-lactating  AI is the same as for non-pregnant women 75 μg/day bone reabsorption capacity induces more relate of calcium —> milk supplied in calcium Regardless of mother’s intake of calcium Hormonally driven process —> not affected by dietary intake Primary source of Ca in human milk ↑Maternal bone resorption Independent of calcium intake Bone loss appears to be regained upon return of ovarian function no more PTHrP secreted since estrogen increases Prolactin stops estrogen which increases bone resorption with PTHrP secretion Calcium Source of Ca for milk production (~ 210 mg/d) could be ↑ Dietary intake ↑ Fractional intestinal absorption ↓ Renal excretion Stimulation of bone resorption Most studies: no difference in blood [1,25(OH) 2D] between lactating & non-lactating women Calcium No ↑ in blood [1,25(OH)2D] in lactating women  Ca absorption not ↑ during lactation Even with low Ca intake (i.e. 750 mg/d) ↑ Renal conservation of Ca occurs during lactation ↑ Ca mobilization from bone + ↓Urinary Ca excretion  Sufficient milk production Calcium Adaptive changes in Ca homeostasis: independent of maternal Ca intake Changes in bone mass related to lack of estrogen Not to increased Ca demand Dietary Calcium > recommendation  does not minimize bone loss Calcium Many studies: no association between previous lactation history & bone mass density or fracture risk post lactation: fracture risk of bone mineral density —> lactation does not induce many risk factors of osteoporosis or increase risk of fraction lactation: mother loses bone density, but not significantly No evidence that Ca intake in lactating women should ↑ RDA for Ca during lactation 1300 mg/day