TABLE 1.

Recommended nutrient intakes for infants and lactating women: United States and Canada (Institute of Medicine)¹

	Milk		Infant AI, units/d		Lactation, units/d
Nutrient	Concentration, units/L	Intake from milk (0–6 mo)2	0–6 mo	7–12 mo	Increment over NPNL RDA3	EAR	RDA	Data	Comments
Thiamin, mg	0.21	0.16	0.2	0.3	+0.3	1.2	1.4	0.21 ± 0.4 mg/L (1).	Stated by IOM (2) but source of value not available.4
Riboflavin, mg	0.35	0.27	0.3	0.4	+0.5	1.3	1.6	Mean of one study (mean: 0.39 mg/L; n = 5) (3) and old WHO report that used a microbiological assay (0.31 mg/L) (4).	No information on participants but intake data suggest unsupplemented (United States). Recognized FAD not detected before 1990 so older values likely underestimates. Source of data from WHO unknown.
Niacin, mg	1.8	1.4	2.0	4.0	+3	13	17	1.8 mg/L from one study (n = 23) (5). After 6 mo, contribution from food was >9 mg NE/d, which was assumed to be too high so an AI of 4 mg NE/d (extrapolated from adults) was used. For women, 1.4 mg/d in milk +1 mg/d to support energy used in milk production.	Supplementation unlikely but not stated (United Kingdom). Range: 1.2–2.8 at 16–244 d. Midfeeding, 4 times/d on 4 d between 16 and 244 d. Microbiological assay. Although tryptophan 210 mg/L, IOM assumed contribution to NEs (1 NE = 1 mg niacin or 60 mg tryptophan) of infants was negligible (2).
Vitamin B-6, mg	0.13	0.1	0.1	0.3	+0.7	1.7	2.0	Value is for intake <2.5 mg/d (n = 6; 0.07–0.18 mg/L) vs. 0.24 for 2.5–5 mg/d (n = 8; 0.19–0.35 mg/L) and 0.31 for >5 mg/d (n = 5; 0.26–0.45 mg/L) (6).	Well-nourished, supplemented and unsupplemented with intakes near the RDA (United States). Samples for 3 wk to 30 mo; 5 samples foremilk/mother over 2 wk. Microbio-logical assay for total vitamin B-6. Some concern that 0.1 mg AI might be low but supported by maternal intake of 1.4 mg where infant PLP was normal and milk 0.12 mg/L (7).
Vitamin B-12, μg	0.42	0.33	0.4	0.5	+0.4	2.4	2.8	0.45 ± 0.265 μg/L; range: 0.01–1.49 μg/L; n = 9 (8). Also compared this with 0.31 μg/L in US vegan mothers with elevated MMA in infants (9) and even lower values where clinical deficiency was present in infants.	Well-nourished Brazilian unsupplemented mothers, EBF infants. Longitudinal samples from 4 d to 3 mo, 265 samples total with variable times of collection. Radioassay may be invalid.
Folate, μg DFE	85	65	65	80	+100	450	500	85 μg/L reported in 3 references from same laboratory since 1986 (10–12), but earlier values dubious depending on analytical method (n = 42). Age 7–12 mo recommendation extrapolated on body weight basis and supported by normal infant status. Assumes 50% bioavailability from diet in lactation.	Samples from both 3 and 6 mo of lactation (10)
Vitamin C, mg	50	39	40	50	+45	100	120	Milk value from synthesis of 3 studies [n = 200 (13), n = 118 (14), n unknown (15)] and stated to be in range of other studies on unsupplemented women (16–18).	Healthy Finnish nonsmokers, infants EBF for ≥3 mo, longitudinal study birth to 12 mo (13); United States, 1 and 6 wk postpartum (14). Very wide range of values.
Vitamin A, μg RAE	485	400	400	500	+400	900	1300	485 ± 85 μg/L (19); n = 3. Age 7–12 mo AI based on intake from milk (291 μg/d) + foods (244 μg/d) in United States and extrapolated from age 0–6 mo based on body weight. For women, CV = + 20% based on half-life of liver retinol.	Well-nourished US women, aged 23–36 y; 176 ± 101 d postpartum; EBF. Complete breast expression, including 2 midafternoon samples/mother.
Vitamin D, IU	—	—	400	400	0	400	600	Milk values not used because known to be very low; AI based on intake for maintaining serum 25(OH)D >50 nmol/L.	For lactation, observed no relation between maternal serum 25(OH)D and maternal BMD, milk, or infant 25(OH)D.
Vitamin E, mg	4.9	3.8	4.0	5.0	+4.0	16	19	Composite of 5 studies with wide range of mean values: 2.3 mg/L (20), 3.5 mg/L (21), 3.7 ± 0.6 mg/L (22), 7.2 ± 3.9 mg/L (n = 24) (23), 8 ± 5 mg/L (n = 13) (24); age 7–12 mo AI increased based on body weight.	12 d to 5 mo of lactation, all measured by HPLC; samples from milk bank after infant fed (23); midfeeding at 10–30 d (St. Lucia) (24).
Vitamin K, μg	2.5	2.0	2.0	2.5	0	—	90 (AI)	Milk value based on 7 studies over wide age range and values of 0.85–9.2 μg/L (25–31). AI assumes high dose given at birth and principally breastfed. Age 7–12 mo increase is based on body weight. No increase for lactation due to low secretion in milk.	Colostrum through 26 wk but time postpartum (for mature milk) assumed to be unimportant. Maternal intake reported in one study and “no supplements” in one study. Remainder did not report.
Iron, mg	0.35	0.27	0.27	6.9 (RDA = 11)	+9 (19–50 y)	6.5	9.0	Milk value based on 9 studies; total n = 202 (32–40); range: 0.03–1.1 mg/L (the highest may be due to contamination). From age 7 to 12 mo, large increase due to use of factorial method. Lactation requirement for absorbed iron = 0.896 basal +0.27 mg in milk, with 18% absorption. 30% CV for lactation.	Mostly well-nourished women, 3 d to 31 mo of lactation. Unclear how mean was calculated for 0–6 mo.
Copper, μg	250	200	200	220	+400	1000	1300	Table of several reports shows copper concentration in breast milk decreases with time. Not clear how 250 and 200 μg/L values were extracted but several references cited (41–43). n = 350 from ∼15 studies. For age 7–12 mo, assumes 100 μg in complementary food. For lactation, assumes 70% absorption.	All stages of lactation.
Zinc, mg	2.5	2.0	2.0	2.5 (EAR), 3.0 (RDA)	+4	10.4	12.0	n = 270 from 12 studies. Marked decline through 6 mo. Milk value from early lactation is generous for age 4–6 mo. Consistent with factorial estimates. For age 7–12 mo, factorial method assumes milk provides only 0.5 mg and complementary foods provide 1.95 mg at 30% absorption.	All stages of lactation.
Calcium, mg	259 ± 59	202	200	260	0	800	1000	AI for infant based on review of milk calcium (44) but provides enough absorbed calcium to meet requirements estimated by factorial method. For age 7–12 mo, assumes 120 mg from milk + 140 mg from solid food. For lactation, evidence of no increase in calcium requirements.	Commented that studies on milk calcium are longstanding with little change. Does vary within a feeding and falls slightly in second 6 mo of lactation.
Magnesium, mg	34	30	30	75	0	255 (19–30 y), 265 (31–50 y)	310 (19–30 y), 320 (31–50 y)	Milk value from review of studies (44). Increase at age 7–12 mo from complementary foods. No increment for lactation due to reduced urinary magnesium and increased bone resorption.	Across first year of lactation but concentration seems constant across this time.
Iodine, μg	146	114	110	130	+140	209	290	146 μg/L (45) but reported mean actually 178 μg/L (29–490 μg/L); n = 37. Within range of other studies (46, 47). For age 7–12 mo based on increase in weight. CV of 20% for lactation.	United States: 14 d to 3.5 y lactation; 61 samples. No correlation with age but correlated with intake. 143 μg/L if iodized salt intake low, 270 μg/L if high.
Selenium, μg	18	14	15	15	+15	59	70	Milk value from 4 studies (48–51); n ≥ 500.	Milk data provided for 14 studies, wide range of values and status. Value selected is for unsupplemented well-nourished women.

¹Data were obtained from the DRIs, IOM, and Food and Nutrition Board (2, 52–54) unless otherwise noted. AI, Adequate Intake; BMD, bone mineral density; DFE, dietary folate equivalent; EAR, Estimated Average Requirement; EBF, exclusively breastfed; IOM, Institute of Medicine; MMA, methylmalonic acid; NE, niacin equivalent; NPNL, nonpregnant, nonlactating; PLP, pyridoxal 5΄-phosphate; RAE, retinol activity equivalent, where 1 RAE = 1 μg all-trans retinol; 25(OH)D, 25-hydroxyvitamin D.

²Calculation of infant intake assumes 0.78 L milk/d consumed from ages 0 to 6 mo.

³Data were calculated by the authors as the RDA for lactation minus the RDA for NPNL women.

⁴Data were cited from a secondary source, because the primary source was not available.

⁵Mean ± SD (all such values).