title: Variation in zinc, calcium, and magnesium concentrations of human milk within a 24-hour period from 1 to 6 months of lactation.
abstract: Longitudinal changes in nutrient levels of human milk have been observed with the progression of lactation, but less is known about changes at different feedings during a 24-h period. In this study, calcium, magnesium, and zinc levels were examined in milk obtained from 49 women at every breast feeding during one 24-h period each month for the first 6 months of lactation. Magnesium and zinc concentrations showed significant diurnal variation at each stage of lactation examined, whereas calcium levels were relatively constant. Maximum variations of 7.5, 17, and 48% were observed within a 24-h period in mean levels of calcium, magnesium, and zinc, respectively. Irrespective of variability, zinc and magnesium concentrations in a single milk sample obtained between 10:00 a.m. and 2:00 p.m. were highly correlated with the mean value of samples collected at each feeding during a 24-h period.
authors.affiliation: Department of Foods and Nutrition, Purdue University, West Lafayette, Indiana 47907.
authors.forename: M V
authors.initials: MV
authors.lastname: Karra
authors.forename: A
authors.initials: A
authors.lastname: Kirksey
mesh_terms: D000328:Adult; D002118:Calcium / Q000378:metabolism*; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D007774:Lactation; D008274:Magnesium / Q000378:metabolism*; D008895:Milk, Human / Q000378:metabolism*; D009994:Osmolar Concentration; D011247:Pregnancy; D013997:Time Factors; D015032:Zinc / Q000378:metabolism*
chemical_list: D008274:Magnesium; D015032:Zinc; D002118:Calcium