Calcium, zinc, and vitamin D in breast milk: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of descriptive and observational studies (level assigned by design analogy).
PubMed 37264448 · doi:10.1186/s13006-023-00564-2
What was done
A systematic search was performed across Embase, MEDLINE, CENTRAL, African Journals Online, and LILACS through November 2022 to identify studies reporting calcium, zinc, and vitamin D concentrations in breast milk from healthy mothers and infants. Random-effects meta-analyses, subgroup analyses, and meta-regressions were conducted to calculate mean concentrations and evaluate influencing factors.
What was found
Across 154 studies, mean breast milk calcium was 261 mg/L (95% CI: 238, 284), decreasing linearly over lactation (calcium [mg/L] = 282 - 0.2331 × days since birth) and influenced by maternal health. Across 242 studies, mean zinc was 2.57 mg/L (95% CI: 2.50, 2.65), which started high postpartum, declined rapidly (zinc [mg/L] = 6 + 0.0005 × days - 2.0266 × log(days)), and was influenced by maternal age, gestational age, and maternal diet. Across 43 studies, mean total antirachitic activity for vitamin D was 58 IU/L (95% CI: 45, 70), mostly composed of 25OHD3, showing wide between-study variation and influence from supplementation, continent, and season.
Why it matters
This study provides comprehensive global baseline concentrations and time-dependent decay equations for calcium, zinc, and vitamin D in breast milk to guide infant nutrition and dietary adequacy assessments.
Limits
The total number of human participants is not specified in the abstract. Breast milk vitamin D concentrations demonstrated wide variation across studies, and the observational nature of the included literature limits causal inferences regarding influencing determinants.
Cited by
- partial Human breast milk contains vitamin D and all eight B vitamins derived from the mother's microbiome.