Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (635 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
The off-white liquid secreted by the mammary glands of humans and other mammals. It contains proteins, sugar, lipids, vitamins, and minerals.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Cow Milk; Milk, Cow; Cow's Milk; Milk, Cow's.
Where it fits in the MeSH classification
- Broader topics
- Bodily Secretions; Fluids and Secretions; Beverages; Dairy Products
- Narrower topics
- Buttermilk; Kefir; Koumiss; Milk Proteins; Milk, Human; Whey; Cultured Milk Products
- See also
- Lactation
Research landscape
PubMed indexes 113,751 records tagged with the MeSH heading “Milk” (counts retrieved 2026-10-31). 26,261 of them (23.1%) were published from 2020 onward, and the busiest period so far is through 1999 with 38,776 records.
Reviews account for 9,200 records (8.1%) and meta-analyses for 735. Randomized controlled trials number 4,417 (3.9%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 38,776 |
| 2000-2009 | 18,831 |
| 2010-2019 | 29,883 |
| 2020 onward | 26,261 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 9,200 | 8.1% |
| Meta-analyses | 735 | 0.6% |
| Randomized controlled trials | 4,417 | 3.9% |
Method: PubMed query "Milk"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Human milk oligosaccharide mediates mutualism between Escherichia coli and Bifidobacterium bifidum | 2026 | Research article Design not recorded in structured metadata | 2 | cc by PMID 42020426 · DOI · PMC13103366 |
| Mammary and respiratory infection of sheep with H5Nx clade 2.3.4.4b viruses with milk-mediated transmission to lambs | 2026 | Research article Design not recorded in structured metadata | 2 | cc by PMID 42102219 · DOI · PMC13155352 |
| Milk fat intake, adiposity, and obesity in Canadian children: findings from the prospective Canadian CHILD Cohort Study | 2026 | Research article Design not recorded in structured metadata | 2 | cc by PMID 42070887 · DOI · PMC13197898 |
Human milk oligosaccharide mediates mutualism between Escherichia coli and Bifidobacterium bifidum [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Infant gut microbiota development involves frequent colonization by Enterobacteriaceae, particularly Escherichia coli, yet their ecological role in healthy infants is unclear.
- Closing excerpt
- coli abundance within the infant host.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (151 words)
Infant gut microbiota development involves frequent colonization by Enterobacteriaceae, particularly Escherichia coli, yet their ecological role in healthy infants is unclear. Here, we analyse longitudinal stool samples from healthy, term-born, breastfed infants (n = 41) and related mothers (n = 30) using shotgun metagenomics and novel computational approaches. Strain-resolved profiling indicates that Bifidobacterium species are frequently shared within families, whereas E. coli derive from external sources, but often persist within individuals. Despite differing ecological strategies, these genera co-exist and share evolutionary adaptations related to lactose acquisition in the infant gut. In vitro, we demonstrate that interactions between E. coli and Bifidobacterium bifidum are mutualistic in co-culture, where E. coli supplies cysteine to its auxotrophic partner, facilitating cooperative degradation of 2'-fucosyllactose, the predominant human milk oligosaccharide. In turn, the liberated monosaccharides sustain E. coli growth, highlighting a cooperative cross-feeding interaction that may contribute to regulating E. coli abundance within the infant host.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42020426 · DOI · PMC13103366
Mammary and respiratory infection of sheep with H5Nx clade 2.3.4.4b viruses with milk-mediated transmission to lambs [2]
Abstract reading summary — source excerpts
- Opening excerpt
- H5Nx clade 2.
- Closing excerpt
- These findings establish sheep as a viable ruminant model for H5N1 and H5N5 infection and highlight previously unidentified transmission dynamics, including milk-mediated and lamb-to-ewe spread, relevant for surveillance and biosecurity in ruminant populations.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (151 words)
H5Nx clade 2.3.4.4b viruses are evolving rapidly, expanding host ranges and threatening animal and public health. In the US, genotype B3.13 dominates dairy outbreaks, while D1.1 is linked to fewer cases. In the UK, an asymptomatic ewe infected with genotype DI.2 raised concerns about ruminant susceptibility. We inoculated lactating and nonlactating sheep with D1.1 (H5N1) and A6 (H5N5) viruses. Intramammary inoculation in lactating sheep caused clinical mastitis, high viral loads in milk, and transmission to suckling lambs, which further spread infection to the uninoculated mammary glands. Both ewes and their lambs seroconverted. Aerosol exposure of nonlactating sheep led to transient respiratory infection, with low-level viral replication, and seroconversion. In vitro, both viruses replicated in sheep mammary epithelial cells. These findings establish sheep as a viable ruminant model for H5N1 and H5N5 infection and highlight previously unidentified transmission dynamics, including milk-mediated and lamb-to-ewe spread, relevant for surveillance and biosecurity in ruminant populations.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42102219 · DOI · PMC13155352
Milk fat intake, adiposity, and obesity in Canadian children: findings from the prospective Canadian CHILD Cohort Study [3]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundGuidelines in Canada, the United States, and other countries recommend that children switch from whole (3.
- Closing excerpt
- These findings challenge current recommendations to limit milk fat in children and may inform future dietary guidelines.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (333 words)
BackgroundGuidelines in Canada, the United States, and other countries recommend that children switch from whole (3.25%) to reduced-fat milk after age 2 years to limit saturated fat intake and prevent obesity, despite these recommendations being derived primarily from adult studies. Emerging pediatric evidence challenges this approach, but prospective data in early school-aged children are scarce.ObjectivesTo test for cross-sectional and longitudinal associations of cow milk-fat content at age 5 years and adiposity indicators and obesity status among 5- and 8-year-old Canadian children.MethodsWe analyzed data from the CHILD Cohort Study, a national longitudinal prospective pregnancy cohort study. At age 5 years, caregivers reported the fat content of cow milk consumed (skim [0%], 1%, 2%, and whole [3.25%]). Anthropometric measures at ages 5 years (N = 2043) and 8 years (N = 1574) included body mass index (BMI) and waist-to-height ratio z-scores; and at age 8 years, fat mass percentage (measured by bioelectric impedance analysis) and obesity (defined using World Health Organization criteria and the new clinical obesity Lancet Commission definitions). Multivariable linear and logistic regression models were adjusted for sociodemographic, lifestyle, and other dietary factors.ResultsAt age 5 years, most children consumed 2% (48.9%) or 3.25% (23.9%) fat from cow milk. Compared with skimmed cow milk, whole (3.25%) cow milk consumption was associated with lower BMI z-score at age 5 years [β: -0.34; 95% confidence interval (CI): -0.54, -0.13] and lower odds of living with obesity [odds ratio (OR): 0.22; 95% CI: 0.07, 0.67]. Whole cow milk consumption at 5 years was also inversely associated with BMI z-score (β: -0.42; 95% CI: -0.72, -0.11), waist-to-height ratio z-score (β: -0.35; 95% CI: -0.63, -0.07), fat mass (β: -1.58; 95% CI: -3.10, -0.06), obesity (OR: 0.31; 95% CI: 0.12, 0.80), and preclinical obesity (OR: 0.25; 95% CI: 0.09, 0.70) at age 8 years.ConclusionsWhole cow milk consumption at age 5 years was associated with lower adiposity and obesity indicators in middle childhood. These findings challenge current recommendations to limit milk fat in children and may inform future dietary guidelines.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42070887 · DOI · PMC13197898
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Breast-feeding and cognitive development: a meta-analysis [4]
- Research article A systematic review and meta-analysis of the nutrient content of preterm and term breast milk [5]
- Research article A Systematic Review and Meta-Analysis of Human Milk Feeding and Morbidity in Very Low Birth Weight Infants [6]
- Research article Milk and dairy consumption and risk of cardiovascular diseases and all-cause mortality: dose-response meta-analysis of prospective cohort studies [7]
- Research article Donor breast milk versus infant formula for preterm infants: systematic review and meta-analysis [8]
- Research article Meta-analysis of the influence of Saccharomyces cerevisiae supplementation on ruminal parameters and milk production of ruminants [9]
References
- Seki D, Pollak S, Kujawska M, Kiu R, Acuna-Gonzalez A, Crouch LI, et al.. Human milk oligosaccharide mediates mutualism between Escherichia coli and Bifidobacterium bifidum. . 2026. PMID 42020426 · DOI · PMC13103366
- Alkie TN, Embury-Hyatt C, Signore AV, Moffat E, Ramos D, Raj S, et al.. Mammary and respiratory infection of sheep with H5Nx clade 2.3.4.4b viruses with milk-mediated transmission to lambs. . 2026. PMID 42102219 · DOI · PMC13155352
- Zeitoun T, Chen ZH, Burgner D, MacKechnie G, Huntington P, Mansell T, et al.. Milk fat intake, adiposity, and obesity in Canadian children: findings from the prospective Canadian CHILD Cohort Study. . 2026. PMID 42070887 · DOI · PMC13197898
- Anderson JW, Johnstone BM, Remley DT. Breast-feeding and cognitive development: a meta-analysis. Am J Clin Nutr. 1999. PMID 10500022 · DOI
- Gidrewicz DA, Fenton TR. A systematic review and meta-analysis of the nutrient content of preterm and term breast milk. BMC Pediatr. 2014. PMID 25174435 · DOI · PMC4236651
- Miller J, Tonkin E, Damarell RA, McPhee AJ, Suganuma M, Suganuma H, et al.. A Systematic Review and Meta-Analysis of Human Milk Feeding and Morbidity in Very Low Birth Weight Infants. Nutrients. 2018. PMID 29857555 · DOI · PMC6024377
- Guo J, Astrup A, Lovegrove JA, Gijsbers L, Givens DI, Soedamah-Muthu SS. Milk and dairy consumption and risk of cardiovascular diseases and all-cause mortality: dose-response meta-analysis of prospective cohort studies. Eur J Epidemiol. 2017. PMID 28374228 · DOI · PMC5437143
- Boyd CA, Quigley MA, Brocklehurst P. Donor breast milk versus infant formula for preterm infants: systematic review and meta-analysis. Arch Dis Child Fetal Neonatal Ed. 2007. PMID 16556615 · DOI · PMC2675323
- Desnoyers M, Giger-Reverdin S, Bertin G, Duvaux-Ponter C, Sauvant D. Meta-analysis of the influence of Saccharomyces cerevisiae supplementation on ruminal parameters and milk production of ruminants. J Dairy Sci. 2009. PMID 19307644 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.