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Table 3 Summary of the studies on circadian changes in human milk macronutrient content

From: Circadian changes in the composition of human milk macronutrients depending on pregnancy duration: a cross-sectional study

ReferenceSiteParticipants (number)Lactation stageMacronutrients investigatedAnalytical methodsResults
Gunther M et al., 1949 [8]Germany88–11 days of lactationFatGerberThe highest concentrations in the morning and at noon and the lowest between 8 PM and 4 AM
Prentice A et al., 1981 [17]Gambia601–18 months after deliveryFatCMTA marked diurnal variation (the highest values in the early morning, the lowest in the late afternoon)
Harzer G et al., 1983 [18]Germany17 (13 German and 4 English)First 5 weeks of lactationLipidThin-layer chromatographyMilk samples from German mothers had their peak lipid
content in the afternoon (noon to 6 PM), while the English samples had their respective peaks in the evening (6 PM to midnight)
Lavine ME et al., 1986 [19]US6 (mothers of term infants)8th week of lactationNitrogen, lipidMicro-Kjeldahl method (nitrogen), modified Folch procedure (lipid)Total nitrogen remained fairly constant during the day; total lipid exhibited significant circadian variation, with peak concentration in the morning (10.00 h) and afternoon (14.00 h) samples
Clark RM, 1987 [20]US7 (mothers of term infants)8th week of lactationProtein, urea nitrogen, free amino acids (taurine, glutamine, glutamic acid)Micro-Kjeldahl method (total nitrogen) Crocker method (urea nitrogen)Concentrations of nitrogen substances in the milk differed significantly among women but were relatively constant during the day
Jackson DA et al., 1988 [21]Thailand25 (mothers of term infants)From the 1st to 9th months after deliveryFatCMTSignificant circadian variation, with maximum values between 16.00–20.00 h and minimum values between 04.00–08.00 h
Lammi-Keefe CJ et al., 1990 [22]US6 (mothers of term infants)8 weeks after deliveryLipid, carbohydrate, protein, caloriesModified Folch procedure (lipid), YSI model 27 Industrial Analyser (lipid), micro- Kjeldahl method (protein), Southgate-Durnin equation (calories)Significant circadian variation of protein content, with maximum values at 6 AM and 6 PM. None of the other components varied significantly.
Stafford J, 1994 [23]Mexico10Not specifiedLipidModified Folch methodSignificant circadian variations of volume and lipid yield were noted, peaking at 8.00–12.00 and 16.00–20.00 h
Weber A et al., 2001 [24]Germany20 (mothers of VLBW infants)The first 4 weeks of lactationProtein, fatBicinchoninic acid method (protein), CMT (fat)Fat but not protein was lower in morning samples than in samples collected later in the day
Lubetzky R et al., 2006 [10]Israel39 (mothers of preterm infants, 26–33 weeks)7–14 days after deliveryFatCMTCMT was significantly higher in evening (between 21.00 h and 24.00) than in morning (between 6.00 h and 9.00 h) samples
Lubetzky R et al., 2007 [9]Israel22 (mothers of preterm infants, 26–31 weeks)2–7 weeks after deliveryFatCMTMean CMT was significantly higher in evening (9 PM to midnight) than morning samples (6–9 AM) during the first 7 weeks of lactation
Sanchez Lopez CL et al., 2011 [25]Spain69 (11 colostral group, 27 transitional group, 31 mature group)<  2 months of lactationTotal nitrogen and protein contentKjeldahl methodIn the group of mature lactating women, protein content was significantly higher during the night-time (20.00 h – 8.00 h) than during the daytime (8.00–20.00 h)
Khan S et al., 2013 [26]Australia15 (mothers of term infants)From the 1st to 6th months after deliveryFat, lactose, total protein, casein, whey protein contentCMT (fat), enzymatic spectrophoto-metric method (lactose), Bradford protein assay (protein)Fat content significantly differed over 24 h (higher during the day and lower at night, with no difference between morning and evening); the concentration of lactose and protein remained the same
Moran-Lev H et al., 2015 [11]Israel32 (mothers of preterm infants, 26–33 weeks)2–7 weeks after deliveryFat, carbohydrate, protein, energyMid-infrared transmission spectroscopyFat and energy contents during the whole period were significantly higher in evening samples; no significant differences between morning and evening in carbohydrates and protein contents
Çetinkaya AK et al., 2017 [27]Turkey52 (mothers of 30 preterm and 22 term infants)5–15 lactation days (n = 27) and > 15 lactation days (n = 25)Protein, fat, carbohydrateMid-infrared transmission spectroscopyNo significant difference was found in the protein, fat, and carbohydrate content of milk samples throughout the day
Hollanders JJ et al., 2019 [28]Netherlands10 (mothers of term infants)1 month after delivery (± 5 days)Cortisol, cortisone levels and fat, carbohydrate and protein contentMid-infrared transmission spectroscopyWhile in all the mothers, a diurnal rhythm of cortisol and cortisone could be seen, no rhythm appeared to be present for fat, carbohydrates, and protein
  1. US United States, VLBW very low birthweight, CMT creamatocrit