Vitamin A Concentration in Human Milk: A Meta-Analysis

Abstract

Humans require vitamin A (VA). However, pooled VA data in human milk is uncommon internationally and offers little support for dietary reference intake (DRIs) revision of infants under 6 months. As a result, we conducted a literature review and a meta-analysis to study VA concentration in breast milk throughout lactation across seven databases by August 2021. Observational or intervention studies involving nursing mothers between the ages of 18 and 45, with no recognized health concerns and who had full-term infants under 48 months were included. Studies in which retinol concentration was expressed as a mass concentration on a volume basis and determined using high-, ultra-, or ultra-fast performance liquid chromatography (HPLC, UPLC, or UFLC) were chosen. Finally, 76 papers involving 9171 samples published between 1985 and 2021 qualified for quantitative synthesis. Results from the random-effects model showed that the VA concentration of healthy term human milk decreased significantly as lactation progressed. VA (µg/L) with 95% CI at the colostrum, transitional, early mature and late mature stages being 920.7 (744.5, 1095.8), 523.7 (313.7, 733.6), 402.4 (342.5, 462.3) and 254.7 (223.7, 285.7), respectively (X2 = 71.36, p < 0.01). Subgroup analysis revealed no significant differences identified in VA concentration (µg/L) between Chinese and non-Chinese samples at each stage, being 1039.1 vs. 895.8 (p = 0.64), 505.7 vs. 542.2(p = 0.88), 408.4 vs. 401.2 (p = 0.92), 240.0 vs. 259.3 (p = 0.41). The findings have significant implications for the revision of DRIs for infants under six months.

Electrochemical sensing of B-complex vitamins: current challenges and future prospects with microfluidic integration

“…The concentration of analytes in real samples, for instance, in food, biological uids (up to nmol), and pharmaceutical formulations (up to mg g −1 ), is low, and the molecular weight of analytes is small compared to coexisting foulants in matrices. 79,80 The presence of interfering species can adversely affect selectivity and sensitivity, and the capture of small-molecule analytes in complex food matrices and the signal transduction of sensing surface changes are challenging for sensors. 81 Many real samples contain complex matrices that can interfere with the electrochemical measurements of vitamins.…”

“…The concentration of analytes in real samples, for instance, in food, biological fluids (up to nmol), and pharmaceutical formulations (up to mg g −1 ), is low, and the molecular weight of analytes is small compared to coexisting foulants in matrices. 79,80…”

Longitudinal Changes in Human Milk Minerals and Vitamins in the Chinese Population: A Scoping Review

“…However, there are only a few review studies that have specifically investigated the longitudinal changes in minerals and vitamins in human milk. For instance, Dror et al focused on iodine and vitamin B-12 [ 13 , 14 ], Zhang H et al examined vitamin A [ 15 ], Xi Y et al reported on vitamin E [ 16 ], and Gidrewicz et al provided data on calcium and phosphorus from 1 to 12 postnatal weeks [ 17 ]. Another study by Yang et al surveyed nine minerals, but they only analyzed milk samples beyond 2 postnatal weeks: by then, the samples contain mature milk.…”

G proteins: introduction of its history, structure, function, and drug development

“…G-proteins are a family of signal transduction proteins playing a quite critical role in the transmission of extracellular signals into the cell [1]. They are involved in numerous physiological processes, including vision [2], olfaction [3], hormone secretion [4], and neurotransmitter release [5]. G-protein coupled receptors (GPCRs) is the largest kind of cell surface receptors and are responsible for Gprotein activation on ligand binding [6].…”