Table 2.

Human milk fatty acid composition (g/100 g of total FA) at different lactation stages (mean ± standard deviation) and number of observations

Sampling days	0–3 days	17 ± 3 days	30 ± 3 days	60 ± 5 days	90 ± 5 days	120 ± 5 days
	N = 269	N = 292	N = 261	N = 241	N = 232	N = 223
SFAs	40.44 ± 4.00	43.20 ± 5.34*	41.82 ± 5.50*	41.09 ± 5.32	41.93 ± 5.40	42.23 ± 5.29
6:0	0.06 ± 0.00 (2)	0.06 ± 0.02 (26)	0.06 ± 0.01 (53)	0.07 ± 0.02 (88)	0.07 ± 0.01 (101)	0.08 ± 0.02 (107)
8:0	0.17 ± 0.09 (22)	0.22 ± 0.06 (253)	0.22 ± 0.06 (225)	0.21 ± 0.06 (216)	0.22 ± 0.06 (209)	0.22 ± 0.06 (191)
10:0	0.45 ± 0.34 (232)	1.63 ± 0.42* (292)	1.53 ± 0.34 (225)	1.44 ± 0.33 (241)	1.45 ± 0.35 (232)	1.44 ± 0.34 (223)
12:0	2.50 ± 1.29 (232)	5.97 ± 2.01* (292)	5.30 ± 1.65* (225)	5.02 ± 1.64 (241)	5.34 ± 1.88 (232)	5.46 ± 1.84 (223)
14:0	5.40 ± 1.51 (232)	6.35 ± 1.97* (292)	5.71 ± 1.76* (225)	5.55 ± 1.66 (241)	5.98 ± 1.93 (232)	6.19 ± 1.93 (223)
16:0	25.39 ± 2.27 (269)	22.51 ± 2.67* (292)	22.39 ± 2.86 (261)	21.94 ± 2.82* (241)	22.10 ± 2.81 (232)	21.94 ± 2.92 (223)
18:0	6.20 ± 1.19 (232)	6.22 ± 1.45 (292)	6.39 ± 1.48 (225)	6.64 ± 1.56 (241)	6.55 ± 1.56 (232)	6.68 ± 1.59 (223)
20:0	0.24 ± 0.09 (246)	0.18 ± 0.05* (277)	0.18 ± 0.03 (243)	0.18 ± 0.04 (221)	0.17 ± 0.04* (207)	0.17 ± 0.04 (194)
24:0	0.25 ± 0.12 (251)	0.10 ± 0.03* (203)	0.08 ± 0.02* (148)	0.07 ± 0.02 (102)	0.07 ± 0.02 (81)	0.07 ± 0.03 (87)
MUFAs	43.29 ± 3.47	40.63 ± 4.56*	41.90 ± 4.58*	42.38 ± 4.54	41.76 ± 4.85	41.34 ± 4.48
16:1 n-7	2.04 ± 0.59 (232)	2.38 ± 0.68* (292)	2.47 ± 0.73 (225)	2.34 ± 0.68 (241)	2.25 ± 0.67 (232)	2.21 ± 0.64* (223)
18:1 n-7	3.08 ± 0.60 (232)	2.51 ± 0.51* (292)	2.48 ± 0.54 (225)	2.41 ± 0.53 (241)	2.36 ± 0.53 (232)	2.38 ± 0.53 (223)
18:1 n-9	36.08 ± 3.14 (269)	34.45 ± 4.29* (292)	35.72 ± 4.25* (261)	36.46 ± 4.25 (241)	35.98 ± 4.48 (232)	35.59 ± 4.17 (223)
trans-18:1	0.57 ± 0.19 (261)	0.62 ± 0.27 (292)	0.62 ± 0.30 (261)	0.64 ± 0.30 (240)	0.65 ± 0.32 (231)	0.66 ± 0.35 (222)
20:1 n-9	0.89 ± 0.20 (261)	0.47 ± 0.13* (292)	0.45 ± 0.13* (261)	0.41 ± 0.11* (240)	0.39 ± 0.12* (228)	0.38 ± 0.12 (217)
22:1 n-9	0.22 ± 0.10 (236)	0.10 ± 0.03* (197)	0.09 ± 0.04* (157)	0.08 ± 0.03* (108)	0.08 ± 0.03 (91)	0.08 ± 0.03 (93)
24:1 n-9	0.41 ± 0.17 (266)	0.11 ± 0.05* (215)	0.08 ± 0.02* (147)	0.07 ± 0.02* (89)	0.07 ± 0.01 (74)	0.08 ± 0.02 (66)
PUFAs	16.26 ± 3.37	16.16 ± 4.37	16.27 ± 4.81	16.53 ± 5.14	16.30 ± 5.30	16.43 ± 5.07
18:2 n-6	12.26 ± 3.26 (269)	13.21 ± 4.22* (292)	13.53 ± 4.67 (261)	13.94 ± 5.02 (241)	13.86 ± 5.18 (232)	14.00 ± 4.95 (223)
20:2 n-6	0.81 ± 0.26 (266)	0.39 ± 0.13* (292)	0.34 ± 0.10* (260)	0.28 ± 0.08* (240)	0.27 ± 0.08* (221)	0.26 ± 0.07 (212)
18:3 n-6	0.11 ± 0.05 (20)	0.12 ± 0.05 (197)	0.13 ± 0.05(195)	0.13 ± 0.04 (180)	0.12 ± 0.04 (163)	0.12 ± 0.04 (144)
20:3 n-6	0.71 ± 0.22 (267)	0.48 ± 0.16* (292)	0.44 ± 0.13* (260)	0.37 ± 0.12* (241)	0.33 ± 0.10* (225)	0.31 ± 0.09 (216)
20:4 n-6 (ARA)	0.91 ± 0.27 (269)	0.58 ± 0.14* (292)	0.50 ± 0.11* (261)	0.46 ± 0.11* (241)	0.44 ± 0.11* (231)	0.44 ± 0.12 (219)
18:3 n-3	0.81 ± 0.39 (264)	0.85 ± 0.48* (269)	0.87 ± 0.52 (261)	0.94 ± 0.61 (241)	0.88 ± 0.49 (232)	0.94 ± 0.55 (221)
20:5 n-3 (EPA)	0.12 ± 0.05 (44)	0.12 ± 0.07 (131)	0.12 ± 0.10* (121)	0.12 ± 0.07 (103)	0.11 ± 0.07 (102)	0.12 ± 0.13 (87)
22:6 n-3 (DHA)	0.68 ± 0.27 (266)	0.47 ± 0.25* (291)	0.40 ± 0.22* (257)	0.35 ± 0.16* (233)	0.34 ± 0.17 (222)	0.34 ± 0.35 (212)
Ratios and sums
ARA/DHA	1.52 ± 0.76 (269)	1.47 ± 0.75 (291)	1.52 ± 0.75 (261)	1.62 ± 0.77 (241)	1.59 ± 0.81* (232)	1.68 ± 0.89 (223)
EPA + DHA	1.03 ± 0.34 (44)	0.71 ± 0.35 (131)	0.62 ± 0.33 (121)	0.54 ± 0.25 (131)	0.53 ± 0.24 (102)	0.57 ± 0.64 (87)
Total fat (g/100 mL)	2.7 ± 1.0	4.0 ± 1.3	4.0 ± 1.5	4.1 ± 1.5	4.0 ± 1.7	4.1 ± 1.8

SFA saturated fatty acid, MUFA monounsaturated fatty acid, PUFA polyunsaturated fatty acid, ARA arachidonic acid, EPA eicosapentaenoic acid, DHA docosahexaenoic acid

*Significant difference between visit and the previous one (p < 0.05)